46 results on '"Congdon, Nathan"'
Search Results
2. Impact of spectacles wear on uncorrected visual acuity among urban migrant primary school children in China: a cluster-randomised clinical trial.
- Author
-
Zhang X, Zhou M, Ma X, Yi H, Zhang H, Wang X, Jin L, Naidoo K, Minto H, Zou H, Rozelle S, Congdon N, and Ma Y
- Subjects
- Child, China epidemiology, Female, Humans, Male, Refractive Errors ethnology, Schools, Transients and Migrants, Treatment Outcome, Vision Screening, Eyeglasses statistics & numerical data, Refraction, Ocular physiology, Refractive Errors therapy, Urban Population, Visual Acuity
- Abstract
Objective: To estimate the effect of providing free spectacles on uncorrected visual acuity (VA) among urban migrant Chinese school children., Design: Exploratory analysis from a parallel cluster-randomised clinical trial., Methods: After baseline survey and VA screening, eligible children were randomised by school to receive one of the two interventions: free glasses and a teacher incentive (tablet computer if ≥80% of children given glasses were wearing them on un-announced examination) (treatment group) or glasses prescription and letter to parents (control group). The primary outcome was uncorrected logarithm of the minimal angle of resolution (LogMAR) VA at study closeout, adjusted for baseline uncorrected VA., Results: Among 4376 randomly selected children, 728 (16.6%, mean age 10.9 years, 51.0% boys) at 94 schools failed VA screening and met eligibility criteria. Of these, 358 children (49.2%) at 47 schools were randomised to treatment and 370 children (50.8%) at 47 schools to control. Among these, 679 children (93.3%) completed follow-up and underwent analysis. Spectacle wear in the treatment and control groups was 68.3% and 29.3% (p<0.001), respectively. Uncorrected final VA for eyes of treatment children was significantly better than control children, adjusting only for baseline VA (difference of 0.039 LogMAR units, 95% CI: 0.008, 0.070, equivalent to 0.39 lines, p=0.014) or baseline VA and other baseline factors (0.040 LogMAR units, 95% CI 0.007 to 0.074, equivalent to 0.40 lines, p=0.020)., Conclusion: We found no evidence that spectacles wear worsens children's uncorrected VA among urban migrant Chinese school children., Competing Interests: Competing interests: NC is Director of Research for Orbis International, a non-governmental organisation which delivers children’s refraction among other services in China and other countries., (© Author(s) (or their employer(s)) 2021. No commercial re-use. See rights and permissions. Published by BMJ.)
- Published
- 2021
- Full Text
- View/download PDF
3. Knowledge, attitudes and eye health-seeking behaviours in a population-based sample of people with diabetes in rural China.
- Author
-
Chen T, Jin L, Zhu W, Wang C, Zhang G, Wang X, Wang J, Yang K, Cochrane GM, Lamoureux EL, Friedman DS, Gilbert S, Lansingh VC, Resnikoff S, Zhao J, Xiao B, He M, and Congdon N
- Subjects
- Aged, China epidemiology, Cross-Sectional Studies, Diabetes Mellitus epidemiology, Diabetic Retinopathy epidemiology, Female, Humans, Incidence, Male, Middle Aged, Retrospective Studies, Surveys and Questionnaires, Diabetes Mellitus psychology, Diabetic Retinopathy psychology, Health Knowledge, Attitudes, Practice, Help-Seeking Behavior, Population Surveillance, Rural Population statistics & numerical data, Visual Acuity
- Abstract
Aims: To assess knowledge of diabetes and acceptance of eye care among people with diabetes in rural China, to improve service uptake., Methods: Population-based study of people in Guangdong, China, with glycosylated haemoglobin A1c≥6.5% and/or known history of diabetes. Between August and November 2014, participants answered a questionnaire (based on Delphi process/previous focus groups) on medical history, demographic characteristics, self-rated health and vision, knowledge about diabetes and diabetic retinopathy, quality of local healthcare, barriers to treatment, likely acceptance of eye exams and treatment, and interventions rated most likely to improve service uptake. Presenting visual acuity was assessed, fundus photography performed and images graded by trained graders. Potential predictors of accepting care were evaluated and confounders adjusted for using logistic regression., Results: A total of 562 people (9.6% (256/5825), mean age 66.2±9.84 years, 207 (36.8%) men) had diabetes, 118 (22.3%) previously diagnosed. 'Very likely' or 'likely' acceptance of laser treatment (140/530=26.4%) was lower than for eye exams (317/530=59.8%, p<0.001). Predictors of accepting both exams and laser included younger age (p<.001) and prior awareness of diabetes diagnosis (p=0.004 and p=0.035, respectively). The leading barrier to receiving diabetes treatment was unawareness of diagnosis (409/454, 97.2%), while interventions rated most likely to improve acceptance of eye exams included reimbursement of travel costs (387/562, 73.0%), video or other health education (359/562, 67.7%) and phone call reminders (346/562, 65.3%)., Conclusions: Improving diagnosis of diabetes, along with incentives, education and communication strategies, is most likely to enhance poor acceptance of diabetic eye care in this setting., Competing Interests: Competing interests: NC works as the Director of Research for Orbis International, a non-governmental organization which carries out programs I eye health, including diabetic retinopathy, in China., (© Author(s) (or their employer(s)) 2021. No commercial re-use. See rights and permissions. Published by BMJ.)
- Published
- 2021
- Full Text
- View/download PDF
4. Using incognito standardised patients to evaluate quality of eye care in China.
- Author
-
Nie J, Zhang L, Gao J, Li J, Zhou Q, Shi Y, Sylvia S, and Congdon N
- Subjects
- Adult, China epidemiology, Female, Humans, Male, Morbidity trends, Refractive Errors epidemiology, Refractive Errors physiopathology, Retrospective Studies, Young Adult, Quality of Health Care standards, Refraction, Ocular physiology, Refractive Errors therapy, Visual Acuity
- Abstract
Background/aims: Few studies have objectively examined the quality of eye care in China. We assessed refractive care using the incognito standardised patient (SP) approach, a gold standard for evaluating clinical practice., Methods: A total of 52 SPs were trained to provide standardised responses during eye examinations, and underwent automated and non-cycloplegic, subjective refraction by a senior ophthalmologist from Zhongshan Ophthalmologic Center, a national-level clinical and research centre. SPs subsequently received subjective refraction and eye exams at a randomly selected sample of 40 public hospitals and 93 private optical shops in Shaanxi, Northwestern China. Difference between expert and local refraction in the better-seeing eye was calculated by the vector diopteric method, and completeness of exams assessed against national standards. SP and provider demographic information and provider clinical experience were recorded., Results: SPs (n=52, mean (range) age, 25.7 (22-31) years, 28.8% male) underwent 133 eye exams (mean total duration 15.0±11.7 min) by 133 local refractionists (24-60 years, 30.3% male). Only 93 (69.9%), 121 (91.0%) and 104 (78.2%) of local refractionists assessed vision, automated and subjective refraction, respectively. The median inaccuracy was -0.25 diopters (D), while 25.6% of results differed by an absolute value of ≥1.0 D and 6.0% by ≥2.0 D. Predictors of inaccurate refraction included spectacle power <-6.0 D (OR=2.66; 95% CI, 1.27 to 5.56), service at a public (vs private) hospital (OR=2.01; 95% CI, 1.11 to 3.63) and provider male sex (OR=2.03; 95% CI, 1.11 to 3.69)., Conclusion: Inaccurate refractions are common in Northwestern China, particularly in public facilities. Important assessments, including subjective refraction, are frequently omitted., Competing Interests: Competing interests: NC is the director of Research for Orbis International, New York, USA, an organisation involved in promoting eye health in low-resource settings., (© Author(s) (or their employer(s)) 2021. No commercial re-use. See rights and permissions. Published by BMJ.)
- Published
- 2021
- Full Text
- View/download PDF
5. Prevalence and causes of vision loss in East Asia in 2015: magnitude, temporal trends and projections.
- Author
-
Cheng CY, Wang N, Wong TY, Congdon N, He M, Wang YX, Braithwaite T, Casson RJ, Cicinelli MV, Das A, Flaxman SR, Jonas JB, Keeffe JE, Kempen JH, Leasher J, Limburg H, Naidoo K, Pesudovs K, Resnikoff S, Silvester AJ, Tahhan N, Taylor HR, and Bourne RRA
- Subjects
- Asia, Eastern epidemiology, Humans, Prevalence, Blindness epidemiology, Visual Acuity
- Abstract
Background: To determine the prevalence and causes of blindness and vision impairment (VI) in East Asia in 2015 and to forecast the trend to 2020., Methods: Through a systematic literature review and meta-analysis, we estimated prevalence of blindness (presenting visual acuity <3/60 in the better eye), moderate-to-severe vision impairment (MSVI; 3/60≤presenting visual acuity <6/18), mild vision impairment (mild VI: 6/18≤presenting visual acuity <6/12) and uncorrected presbyopia for 1990, 2010, 2015 and 2020. A total of 44 population-based studies were included., Results: In 2015, age-standardised prevalence of blindness, MSVI, mild VI and uncorrected presbyopia was 0.37% (80% uncertainty interval (UI) 0.12%-0.68%), 3.06% (80% UI 1.35%-5.16%) and 2.65% (80% UI 0.92%-4.91%), 32.91% (80% UI 18.72%-48.47%), respectively, in East Asia. Cataract was the leading cause of blindness (43.6%), followed by uncorrected refractive error (12.9%), glaucoma, age-related macular degeneration, corneal diseases, trachoma and diabetic retinopathy (DR). The leading cause for MSVI was uncorrected refractive error, followed by cataract, age-related macular degeneration, glaucoma, corneal disease, trachoma and DR. The burden of VI due to uncorrected refractive error, cataracts, glaucoma and DR has continued to rise over the decades reported., Conclusions: Addressing the public healthcare barriers for cataract and uncorrected refractive error can help eliminate almost 57% of all blindness cases in this region. Therefore, public healthcare efforts should be focused on effective screening and effective patient education, with access to high-quality healthcare., Competing Interests: Competing interests: JBJ: Consultant for Mundipharma Co. (Cambridge, UK); Patent holder with Biocompatibles UK Ltd. (Farnham, Surrey, UK) (Title: Treatment of eye diseases using encapsulated cells encoding and secreting neuroprotective factor and/or anti-angiogenic factor; Patent number: 20120263794), and Patent application with University of Heidelberg (Heidelberg, Germany) (Title: Agents for use in the therapeutic or prophylactic treatment of myopia or hyperopia; Europäische Patentanmeldung 15 000 771.4). JHK: consultant for Gilead (DSMC Chair), Santen (protocol design). SR: consultant for Brien Holden Vision Institute., (© Author(s) (or their employer(s)) 2020. No commercial re-use. See rights and permissions. Published by BMJ.)
- Published
- 2020
- Full Text
- View/download PDF
6. Validity and feasibility of a self-administered home vision examination in Yueqing, China: a cross-sectional study.
- Author
-
Ge Z, Li L, Lohfeld L, Lu C, Congdon N, Lin S, Deng Y, Lan Y, Zhang S, Hou L, Zhou W, Cui L, Qu J, and Liang Y
- Subjects
- Adult, China, Cross-Sectional Studies, Feasibility Studies, Female, Health Knowledge, Attitudes, Practice, Humans, Male, Middle Aged, Odds Ratio, Program Evaluation, Reproducibility of Results, Sensitivity and Specificity, Social Media statistics & numerical data, Socioeconomic Factors, Time Factors, Vision Screening organization & administration, Family Characteristics, Self-Testing, Vision Screening methods, Visual Acuity
- Abstract
Objective: To investigate the validity and feasibility of a self-administered home vision examination programme in China., Design: Cross-sectional study., Setting: Yueqing, China., Participants: A two-stage convenience sampling procedure was used to randomly select 600 households from 30 communities participating in the Yueqing Eye Study (YES). The aim of YES is to encourage home-based vision screening, reporting of visual acuity (VA) annually through social media and encouraging people to attend follow-up clinic appointments as a way to improve eye care access for adults with VA ≤+0.5 log of the minimum angle of resolution (logMAR)., Interventions: Household screeners (one per household) who tested other family members' VA completed a questionnaire on family structure, demographic information and knowledge about screening procedures. Other family members then underwent confirmatory VA testing by researchers., Outcome Measures: The completion rate of home-based VA screening, its sensitivity and specificity were used to evaluate validity. Factors that determined whether families participated in the self-VA screening were used to evaluate feasibility., Results: 345 (66%) of the 523 (87.2%) households with valid data form their home-based vision examinations also were retested by researchers. There was no statistically significant difference in scores on the family-administerd or researcher-administerd VA test (VA≤+0.5 logMAR, p=0.607; VA >+0.5 logMAR, p=0.612). The sensitivity and specificity of home-based vision screening were 80.5% (95% CI 70.2% to 86.9%) and 95.1% (95% CI 92.6% to 96.8%), respectively. 14.7% (77/523) of tested respondents had VA ≤+0.5 logMAR. Predictors of performing home screening for VA remaining in regression models included higher economic status ('fair and above' vs 'poor': OR 1.74; 95% CI 1.08 to 2.76; p=0.022), age (<45 years vs ≥45 years: OR 0.46; 95% CI 0.25 to 0.85; p=0.014) and living in a nuclear (OR 5.17; 95% CI 2.86 to 9.36; p<0.001) or extended family (OR 8.37; 95% CI 4.93 to 14.20; p<0.001)., Conclusion: Self-administered home vision screening is reliable and highly accepted by Chinese adults., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2020. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)
- Published
- 2020
- Full Text
- View/download PDF
7. Effect of Chinese eye exercises on change in visual acuity and eyeglasses wear among school-aged children in rural China: a propensity-score-matched cohort study.
- Author
-
Wang H, Qian Y, Congdon N, Boswell M, Rozelle S, and Ma X
- Subjects
- Acupressure, Acupuncture Points, Child, China, Cohort Studies, Female, Humans, Male, Surveys and Questionnaires, Eyeglasses, Massage methods, Oculomotor Muscles physiopathology, Visual Acuity
- Abstract
Background: Daily "eye exercises," massaging of periocular acupuncture pressure points, have been part of China's national vision care policy in schools for some 50 years. However, the effect of eye exercises on myopia progression and eyeglasses wear has not been definitively investigated. This study evaluates the effectiveness of eye exercises on visual acuity and the propensity of rural children to wear eyeglasses., Methods: Cohort study in 252 randomly-selected rural schools with baseline in September 2012 and follow up surveys 9 and 21 months later. Outcomes were assessed using propensity-score matching (PSM), multivariate linear regression and logistic regression to adjust for differences between children performing and not performing eye exercises., Results: Among 19,934 children randomly selected for screening, 2374 myopic (spherical equivalent refractive error ≤ - 0.5 diopters in either eye) children (11.9%, mean age 10.5 [Standard Error 1.08] years, 48.5% boys) had VA in either eye ≤6/12 without eyeglasses correctable to > 6/12 with eyeglasses. Among these who completed the 21-month follow up, 1217 (58.2%) children reported practicing eye exercises on school days and 874 (41.8%) did not. After propensity-score matching, 1652 (79%) children were matched: 826 (50%) in the Eye Exercises group and 826 (50%) in the No Exercise group. Performing eye exercises was not associated with change in LogMAR uncorrected visual acuity and wear of eyeglasses, using either logistic regression or PSM at 9 or 21 months., Conclusions: We found no evidence for an effect of eye exercises on change in vision or eyeglasses wear., Trial Registration: The original trial (Registration site: http://isrctn.org. Registration number: ISRCTN03252665) was retrospectively registered 25/09/2012.
- Published
- 2020
- Full Text
- View/download PDF
8. Association of visual acuity with educational outcomes: a prospective cohort study.
- Author
-
Jan C, Li SM, Kang MT, Liu L, Li H, Jin L, Qin X, Congdon N, and Wang N
- Subjects
- Adolescent, Child, Educational Status, Eyeglasses, Female, Follow-Up Studies, Humans, Male, Prospective Studies, Quality of Life, Refraction, Ocular physiology, Refractive Errors therapy, Socioeconomic Factors, Surveys and Questionnaires, Academic Performance, Refractive Errors physiopathology, Visual Acuity physiology
- Abstract
Background/aim: To quantify the impact of baseline presenting visual acuity (VA), refractive error and spectacles wear on subsequent academic performance among Chinese middle school children., Methods: A prospective, longitudinal, school-based study on grade 7 Chinese children (age, mean±SD, 12.7±0.5 years, range=11.1-15.9) at four randomly selected middle schools in Anyang, China. Comprehensive eye examinations including cycloplegic autorefraction were performed at baseline, and information on demographic characteristics, known risk factors for myopia and spectacle wear was collected. Academic test scores for all subjects in the curriculum were obtained from the local Bureau of Education. Main outcome measure was total test scores for five subjects at the end of grade 9, adjusted for total scored at the beginning of grade 7., Results: Among 2363 eligible children, 73.1% (1728/2363) had seventh grade test scores available. 93.9% (1623/1728) completed eye examinations, and 98.5% (1599/1623) of these had ninth grade test scores. Adjusting only for baseline test score, the following were significantly associated with higher ninth grade scores: younger age, male sex, less time outdoors, better baseline presenting VA, higher parental education and income and parental myopia, but refractive error and spectacle wear were not. In the full multivariate model, baseline test score (p<0.001), presenting VA (p<0.01), age (p<0.001), quality of life (p<0.05) and parental education (p<0.001) and myopia (either: p<0.05; both: p<0.05) remained significantly associated with better ninth grade scores., Conclusions: In this longitudinal study, better presenting VA, but not cycloplegic refractive error or spectacle wear, was significantly associated with subsequent academic performance., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2019. No commercial re-use. See rights and permissions. Published by BMJ.)
- Published
- 2019
- Full Text
- View/download PDF
9. The cost-effectiveness of alternative vision screening models among preschool children in rural China.
- Author
-
Wang L, Congdon N, Hogg RE, Zhang S, Li M, Shi Y, Jin L, He F, Wang H, Boswell M, and Iyer M
- Subjects
- Child, Preschool, China epidemiology, Cost-Benefit Analysis, Eyeglasses, Female, Humans, Male, Prevalence, Refractive Errors economics, Refractive Errors physiopathology, Vision Screening methods, Refractive Errors diagnosis, Rural Population, Vision Screening economics, Visual Acuity
- Abstract
Purpose: To explore the accuracy and cost-effectiveness of three vision screening models among preschool children in rural China., Methods: Vision screening was carried out among children aged 4-5 years in 65 preschools in two counties in Northwest China, using Crowded Single Lea Symbols to test visual acuity. Children were assigned randomly by school to one of three screening models: screening by teachers (15 schools, 1835 children), local optometrists (30 schools, 1718 children) or volunteers (20 schools, 2183 children). Children identifying ≥2 symbols incorrectly in either eye failed screening. Accuracy of screening was compared with screenings executed by experienced optometrists among 141 children selected randomly from the three screening models. Direct and indirect costs for each model were assessed. Costs to detect a true case failed screening were estimated., Results: The sensitivity for three models ranged from 76.9% to 87.5%, specificity from 84.9% to 86.7% and standardized positive predictive value from 83.7% to 85.7%. None differed significantly between models. The costs per case detected were $37.53, $59.14 and $52.19 for the teachers, local optometrists and volunteers. In producing the cost estimates for teacher screening and local optometrist screening models, we used a salary payment that was identical for both models (with the salary being equal to that of the optometrist). The teacher screening model was the most cost-effective., Conclusion: Accuracy of screening by teachers, local optometrists and volunteers was the same in this setting, but the use of teachers was most cost-effective, reducing the cost per case detected by almost 40%., (© 2018 Acta Ophthalmologica Scandinavica Foundation. Published by John Wiley & Sons Ltd.)
- Published
- 2019
- Full Text
- View/download PDF
10. Impact of various types of near work and time spent outdoors at different times of day on visual acuity and refractive error among Chinese school-going children.
- Author
-
Guan H, Yu NN, Wang H, Boswell M, Shi Y, Rozelle S, and Congdon N
- Subjects
- Child, China, Female, Humans, Logistic Models, Male, Time Factors, Leisure Activities, Refractive Errors physiopathology, Schools, Visual Acuity physiology
- Abstract
Background: Various types of near work have been suggested to promote the incidence and progression of myopia, while outdoor activity appears to prevent or retard myopia. However, there is a lack of consensus on how to interpret these results and translate them into effective intervention strategies. This study examined the association between visual acuity and time allocated to various activities among school-going children., Methods: Population-based survey of 19,934 students in grade 4 and 5 from 252 randomly selected rural primary schools in Northwest China in September 2012. This survey measured visual acuity and collected self-reported data on time spent outdoors and time spent doing various types of near activities., Results: Prolonged (>60 minutes/day) computer usage (-0.025 LogMAR units, P = .011) and smartphone usage (-0.041 LogMAR units, P = .001) were significantly associated with greater refractive error, while television viewing and after-school study were not. For time spent outdoors, only time around midday was significantly associated with better uncorrected visual acuity. Compared to children who reported no midday time outdoors, those who spent time outdoors at midday for 31-60 minutes or more than 60 minutes had better uncorrected visual acuity by 0.016 LogMAR units (P = .014) and 0.016 units (P = .042), respectively., Conclusions: Use of smart phones and computers were associated with declines in children's vision, while television viewing was not. Statistically significant associations between outdoor time at midday and reduced myopia may support the hypothesis that light intensity plays a role in the protective effects of outdoor time., Competing Interests: Luxottica-China (Shanghai) is one of the funders of this study. The funders had no role in the design and conduct of the study; collection, management, analysis, and interpretation of the data; preparation, review, or approval of the manuscript; and decision to submit the manuscript for publication. Funding from this this commercial funder does not involve any agreement related to employment, consultancy, patents, products in development, marketed products, etc. We confirm that this does not alter our adherence to PLOS ONE policies on sharing data and materials. There are no restrictions on sharing of data and/or materials.
- Published
- 2019
- Full Text
- View/download PDF
11. Population prevalence of myopia, glasses wear and free glasses acceptance among minority versus Han schoolchildren in China.
- Author
-
Hu M, Zhou Y, Huang S, Congdon N, Jin L, Wang X, Hogg R, Zhang H, Cun Y, Yang L, Li X, and Liang C
- Subjects
- Child, China epidemiology, Female, Humans, Male, Myopia physiopathology, Prevalence, Eyeglasses, Minority Groups, Myopia epidemiology, Refraction, Ocular, Surveys and Questionnaires, Visual Acuity
- Abstract
Aim: To measure myopia, glasses wear and free glasses acceptance among minority and Han children in China., Methods: Visual acuity testing and questionnaires assessing ethnicity, study time, and parental and teacher factors were administered to a population-based sample of 9-12 year old minority and Han children in Yunnan and Guangdong, and their teachers and parents. Refraction was performed on children with uncorrected visual acuity (VA) < = 6/12 in either eye, and acceptance of free glasses assessed., Main Outcome Measures: Baseline myopia (uncorrected visual acuity < = 6/12 in > = 1 eye and spherical equivalent refractive power < = -0.5D in both eyes); baseline glasses wear; free glasses acceptance., Results: Among 10,037 children (mean age 10.6 years, 52.3% boys), 800 (8.0%) were myopic, 4.04% among Yunnan Minority children (OR 0.47, 95%CI 0.33, 0.67, P<0.001), 6.48% in Yunnan Han (OR 0.65, 95%CI 0.45, 0.93, P = 0.019), 9.87% in Guangdong Han (Reference). Differences remained significant after adjusting for study time and parental glasses wear. Difference in baseline glasses ownership (Yunnan Minority 4.95%, Yunnan Han 6.15%, Guangdong Han 15.3%) was not significant after adjustment for VA. Yunnan minority children (71.0%) were more likely than Yunnan Han (59.6%) or Guangdong Han (36.8%) to accept free glasses. The difference was significant after adjustment only compared to Guangdong Han (OR 3.34, 95% CI 1.62, 6.90, P = 0.001)., Conclusion: Myopia is more common among Han children and in wealthier Guangdong. Baseline differences in glasses wear could be explained by student, teacher and parental factors. Yunnan Minority children were more likely to accept free glasses., Competing Interests: The authors have declared that no competing interests exist.
- Published
- 2019
- Full Text
- View/download PDF
12. Barriers, Costs, and Attitudes Toward Pediatric Cataract Surgery at Two Large Facilities in China and India.
- Author
-
Wang J, Jin L, Lu Q, Borah RR, Ali R, Li J, Chakraborti C, Kumar M, Pan J, Gilbert C, and Congdon N
- Subjects
- Cataract economics, Child, Child, Preschool, China epidemiology, Female, Humans, India epidemiology, Male, Retrospective Studies, Socioeconomic Factors, Surveys and Questionnaires, Attitude, Cataract epidemiology, Cataract Extraction statistics & numerical data, Health Care Costs trends, Hospitals, High-Volume statistics & numerical data, Rural Population, Visual Acuity
- Abstract
Purpose: To better understand barriers of costs and attitudes toward pediatric cataract surgery in China and India., Methods: From January 2014 to June 2015, families of children ≤ 10 years old about to undergo or having completed surgery for bilateral, non-traumatic cataract at two tertiary centers in China and India completed questionnaires regarding their demographic characteristics, financial status, living environment, health seeking behaviors, and medical burden., Results: In China, 38 children (23 boys [60.5%], mean age 3.11 ± 2.88 years) were un-operated, and 44 (26 boys [59.1%], mean age 5.09 +/- 2.17 years) had undergone surgery, while in India there were 60 (44 boys [73.3%], mean age 4.61 +/- 3.32 years) and 39 (29 boys [74.4%], mean age 6.45 +/- 2.74 years) children respectively, 181 in total. Chinese children were younger at presentation (p ≤ 0.03 for both operated and un-operated) and also when cataract was detected (median [inter quartile range] 10 [3-34] versus 24 [6-60] months [p = 0.06] for un-operated, 5 [2-12] versus 36 [8-72] months [p < 0.001] for operated). Maternal education levels were lower in India (48.3% and 51.3% with elementary education only among un-operated [p = 0.11] and operated [p = 0.006] families in India versus 27.0% and 20.5% in China), as were rates of consulting medical practitioners for illness (44.7% and 36.4% for un-operated [p < 0.001] and operated [p = 0.001] in China versus 10% and 5.13% in India)., Conclusions: Socioeconomic challenges to securing cataract surgery may be greater, and delays in obtaining surgery longer, in India compared to China, if these facilities are representative.
- Published
- 2019
- Full Text
- View/download PDF
13. Avoidable Waste in Ophthalmic Epidemiology: A Review of Blindness Prevalence Surveys in Low and Middle Income Countries 2000-2014.
- Author
-
Ramke J, Kuper H, Limburg H, Kinloch J, Zhu W, Lansingh VC, Congdon N, Foster A, and Gilbert CE
- Subjects
- Blindness physiopathology, Humans, Income, Retrospective Studies, Blindness epidemiology, Developing Countries, Health Surveys, Visual Acuity
- Abstract
Purpose: Sources of avoidable waste in ophthalmic epidemiology include duplication of effort, and survey reports remaining unpublished, gaining publication after a long delay, or being incomplete or of poor quality. The aim of this review was to assess these sources of avoidable waste by examining blindness prevalence surveys undertaken in low and middle income countries (LMICs) between 2000 and 2014., Methods: On December 1, 2016 we searched MEDLINE, EMBASE and Web of Science databases for cross-sectional blindness prevalence surveys undertaken in LMICs between 2000 and 2014. All surveys listed on the Rapid Assessment of Avoidable Blindness (RAAB) Repository website ("the Repository") were also considered. For each survey we assessed (1) availability of scientific publication, survey report, summary results tables and/or datasets; (2) time to publication from year of survey completion and journal attributes; (3) extent of blindness information reported; and (4) rigour when information was available from two sources (i.e. whether it matched)., Results: Of the 279 included surveys (from 68 countries) 186 (67%) used RAAB methodology; 146 (52%) were published in a scientific journal, 57 (20%) were published in a journal and on the Repository, and 76 (27%) were on the Repository only (8% had tables; 19% had no information available beyond registration). Datasets were available for 50 RAABs (18% of included surveys). Time to publication ranged from <1 to 11 years (mean, standard deviation 2.8 ± 1.8 years). The extent of blindness information reported within studies varied (e.g. presenting and best-corrected, unilateral and bilateral); those with both a published report and Repository tables were most complete. For surveys published and with RAAB tables available, discrepancies were found in reporting of participant numbers (14% of studies) and blindness prevalence (15%)., Conclusion: Strategies are needed to improve the availability, consistency, and quality of information reported from blindness prevalence surveys, and hence reduce avoidable waste.
- Published
- 2018
- Full Text
- View/download PDF
14. Cluster-randomized controlled trial of the effects of free glasses on purchase of children's glasses in China: The PRICE (Potentiating Rural Investment in Children's Eyecare) study.
- Author
-
Wang X, Congdon N, Ma Y, Hu M, Zhou Y, Liao W, Jin L, Xiao B, Wu X, Ni M, Yi H, Huang Y, Varga B, Zhang H, Cun Y, Li X, Yang L, Liang C, Huang W, Rozelle S, and Ma X
- Subjects
- Child, China, Commerce, Female, Humans, Investments, Male, Prescriptions economics, Refractive Errors economics, Refractive Errors physiopathology, Rural Population, Schools economics, Eyeglasses economics, Refractive Errors prevention & control, Visual Acuity physiology
- Abstract
Background: Offering free glasses can be important to increase children's wear. We sought to assess whether "Upgrade glasses" could avoid reduced glasses sales when offering free glasses to children in China., Methods: In this cluster-randomized, controlled trial, children with uncorrected visual acuity (VA)< = 6/12 in either eye correctable to >6/12 in both eyes at 138 randomly-selected primary schools in 9 counties in Guangdong and Yunnan provinces, China, were randomized by school to one of four groups: glasses prescription only (Control); Free Glasses; Free Glasses + offer of $15 Upgrade Glasses; Free Glasses + offer of $30 Upgrade Glasses. Spectacle purchase (main outcome) was assessed 6 months after randomization., Results: Among 10,234 children screened, 882 (8.62%, mean age 10.6 years, 45.5% boys) were eligible and randomized: 257 (29.1%) at 37 schools to Control; 253 (28.7%) at 32 schools to Free Glasses; 187 (21.2%) at 31 schools to Free Glasses + $15 Upgrade; and 185 (21.0%) at 27 schools to Free Glasses +$30 Upgrade. Baseline ownership among these children needing glasses was 11.8% (104/882), and 867 (98.3%) children completed follow-up. Glasses purchase was significantly less likely when free glasses were given: Control: 59/250 = 23.6%; Free glasses: 32/252 = 12.7%, P = 0.010. Offering Upgrade Glasses eliminated this difference: Free + $15 Upgrade: 39/183 = 21.3%, multiple regression relative risk (RR) 0.90 (0.56-1.43), P = 0.65; Free + $30 Upgrade: 38/182 = 20.9%, RR 0.91 (0.59, 1.42), P = 0.69., Conclusions: Upgrade glasses can prevent reductions in glasses purchase when free spectacles are provided, providing important program income., Trial Registration: ClinicalTrials.gov Identifier: NCT02231606. Registered on 31 August 2014.
- Published
- 2017
- Full Text
- View/download PDF
15. A need for standardization in visual acuity measurement.
- Author
-
Patel H, Congdon N, Strauss G, and Lansingh C
- Subjects
- Humans, Reference Standards, Vision Tests methods, Vision Tests standards, Visual Acuity physiology
- Abstract
Standardization of terminologies and methods is increasingly important in all fields including ophthalmology, especially currently when research and new technology are rapidly driving improvements in medicine. This review highlights the range of notations used by vision care professionals around the world for vision measurement, and the challenges resulting from this practice. The global community is urged to move toward a uniform standard.
- Published
- 2017
- Full Text
- View/download PDF
16. Age-Specific Prevalence of Visual Impairment and Refractive Error in Children Aged 3-10 Years in Shanghai, China.
- Author
-
Ma Y, Qu X, Zhu X, Xu X, Zhu J, Sankaridurg P, Lin S, Lu L, Zhao R, Wang L, Shi H, Tan H, You X, Yuan H, Sun S, Wang M, He X, Zou H, and Congdon N
- Subjects
- Age Distribution, Age Factors, Child, Child, Preschool, China epidemiology, Cross-Sectional Studies, Female, Humans, Male, Prevalence, Prognosis, Refractive Errors physiopathology, Refractive Errors rehabilitation, Risk Factors, Vision Tests, Refraction, Ocular physiology, Refractive Errors epidemiology, Visual Acuity, Visually Impaired Persons
- Abstract
Purpose: We assessed changes in age-specific prevalence of refractive error at the time of starting school, by comparing preschool and school age cohorts in Shanghai, China., Methods: A cross-sectional study was done in Jiading District, Shanghai during November and December 2013. We randomly selected 7 kindergartens and 7 primary schools, with probability proportionate to size. Chinese children (n = 8398) aged 3 to 10 years were enumerated, and 8267 (98.4%) were included. Children underwent distance visual acuity assessment and refraction measurement by cycloplegic autorefraction and subjective refraction., Results: The prevalence of uncorrected visual acuity (UCVA), presenting visual acuity, and best-corrected visual acuity in the better eye of ≤20/40 was 19.8%, 15.5%, and 1.7%, respectively. Among those with UCVA ≤ 20/40, 93.2% could achieve visual acuity of ≥20/32 with refraction. Only 28.7% (n = 465) of children with UCVA in the better eye of ≤20/40 wore glasses. Prevalence of myopia (spherical equivalent ≤-0.5 diopters [D] in at least one eye) increased from 1.78% in 3-year-olds to 52.2% in 10-year-olds, while prevalence of hyperopia (spherical equivalent ≥+2.0 D) decreased from 17.8% among 3-year-olds to 2.6% by 10 years of age. After adjusting for age, attending elite "high-level" school was statistically associated with greater myopia prevalence., Conclusions: The prevalence of myopia was lower or comparable to that reported in other populations from age 3 to 5 years, but increased dramatically after 6 years, consistent with a strong environmental role of schooling on myopia development.
- Published
- 2016
- Full Text
- View/download PDF
17. Reply.
- Author
-
Ma X, Congdon N, Yi H, Pang X, Zhou Z, Meltzer ME, He M, Yizhi L, Shi Y, and Rozelle S
- Subjects
- Female, Humans, Male, Eyeglasses standards, Refraction, Ocular, Refractive Errors therapy, Visual Acuity, Visually Impaired Persons rehabilitation
- Published
- 2016
- Full Text
- View/download PDF
18. Safety of Spectacles for Children's Vision: A Cluster-Randomized Controlled Trial.
- Author
-
Ma X, Congdon N, Yi H, Zhou Z, Pang X, Meltzer ME, Shi Y, He M, Liu Y, and Rozelle S
- Subjects
- Child, China epidemiology, Female, Humans, Male, Prevalence, Refractive Errors epidemiology, Refractive Errors physiopathology, Rural Population, Schools, Eyeglasses standards, Refraction, Ocular, Refractive Errors therapy, Visual Acuity, Visually Impaired Persons rehabilitation
- Abstract
Purpose: To study safety of children's glasses in rural China, where fear that glasses harm vision is an important barrier for families and policy makers., Design: Exploratory analysis from a cluster-randomized, investigator-masked, controlled trial., Methods: Among primary schools (n = 252) in western China, children were randomized by school to 1 of 3 interventions: free glasses provided in class, vouchers for free glasses at a local facility, or glasses prescriptions only (Control group). The main outcome of this analysis is uncorrected visual acuity after 8 months, adjusted for baseline acuity., Results: Among 19 934 children randomly selected for screening, 5852 myopic (spherical equivalent refractive error ≤-0.5 diopters) eyes of 3001 children (14.7%, mean age 10.5 years) had VA ≤6/12 without glasses correctable to >6/12 with glasses, and were eligible. Among these, 1903 (32.5%), 1798 (30.7%), and 2151 (36.8%) were randomized to Control, Voucher, and Free Glasses, respectively. Intention-to-treat analyses were performed on all 1831 (96.2%), 1699 (94.5%), and 2007 (93.3%) eyes of children with follow-up in Control, Voucher, and Free Glasses groups. Final visual acuity for eyes of children in the treatment groups (Free Glasses and Voucher) was significantly better than for Control children, adjusting only for baseline visual acuity (difference of 0.023 logMAR units [0.23 vision chart lines, 95% CI: 0.03, 0.43]) or for other baseline factors as well (0.025 logMAR units [0.25 lines, 95% CI 0.04, 0.45])., Conclusion: We found no evidence that spectacles promote decline in uncorrected vision with aging among children., (Copyright © 2015 Elsevier Inc. All rights reserved.)
- Published
- 2015
- Full Text
- View/download PDF
19. Visual outcomes of cataract surgery performed by supervised novice surgeons during training in rural China.
- Author
-
Huang W, Ye R, Liu B, Chen Q, Huang G, Liu Y, Friedman DS, Congdon NG, Ling J, and He M
- Subjects
- Aged, Aged, 80 and over, China, Educational Measurement, Female, Hospitals, County, Hospitals, Rural, Humans, Intraoperative Complications, Male, Middle Aged, Patient Satisfaction, Postoperative Complications, Refraction, Ocular physiology, Retrospective Studies, Rural Population, Treatment Outcome, Clinical Competence standards, Education, Medical, Graduate, Ophthalmology education, Phacoemulsification education, Visual Acuity physiology
- Abstract
Background: To assess the outcomes of cataract surgery performed by novice surgeons during training in a rural programme. DESIGN : Retrospective study., Participants: Three hundred thirty-four patients operated by two trainees under supervision at rural Chinese county hospitals., Methods: Two trainees performed surgeries under supervision. Visual acuity, refraction and examinations were carried out 3 months postoperatively., Main Outcome Measures: Postoperative uncorrected visual acuity, pinhole visual acuity, causes of visual impairment (postoperative uncorrected visual acuity < 6/18) RESULTS: Among 518 operated patients, 426 (82.2%) could be contacted and 334 (64.4% of operated patients) completed the examinations. The mean age was 74.1 ± 8.8 years and 62.9% were women. Postoperative uncorrected visual acuity was available in 372 eyes. Among them, uncorrected visual acuity was ≥6/18 in 278 eyes (74.7%) and <6/60 in 60 eyes (16.1%), and 323 eyes (86.8%) had pinhole visual acuity ≥ 6/18 and 38 eyes (10.2%) had pinhole visual acuity < 6/60. Main causes of visual impairment were uncorrected refractive error (63.9%) and comorbid eye disease (24.5%). Comorbid eye diseases associated with pinhole visual acuity < 6/60 (n = 23, 6.2%) included glaucoma, other optic nerve atrophy, vitreous haemorrhage and retinal detachment., Conclusions: The findings suggest that hands-on training remains safe and effective even when not implemented in centralized training centres. Further refinement of the training protocol, providing postoperative refractive services and more accurate preoperative intraocular lens calculations, can help optimize outcomes., (© 2012 The Authors. Clinical and Experimental Ophthalmology © 2012 Royal Australian and New Zealand College of Ophthalmologists.)
- Published
- 2013
- Full Text
- View/download PDF
20. Five-year incidence and postoperative visual outcome of cataract surgery in urban southern China: the Liwan Eye Study.
- Author
-
Huang W, Zheng Y, Wang L, Huang S, Liu B, Jin L, Congdon NG, and He M
- Subjects
- Aged, Cataract epidemiology, China epidemiology, Female, Humans, Incidence, Lens Implantation, Intraocular statistics & numerical data, Male, Middle Aged, Postoperative Period, Prospective Studies, Treatment Outcome, Vision Disorders physiopathology, Asian People ethnology, Phacoemulsification statistics & numerical data, Urban Population statistics & numerical data, Vision Disorders epidemiology, Visual Acuity physiology, Visually Impaired Persons statistics & numerical data
- Abstract
Purpose: To determine the 5-year incidence and visual outcome of cataract surgery in an adult urban Chinese population., Methods: A comprehensive eye examination was performed at baseline and 5 years later on subjects participating in a population-based study. Incident cataract surgery was defined as having undergone surgery in either eye during the 5-year period. Postoperative visual impairment (PVI) was defined as visual acuity (VA) <6/18 based on both presenting VA (PVA) and best corrected VA (BCVA) in the operated eye., Results: Among the 1405 baseline participants, 75% (924) of survivors were seen at the 5-year follow-up visit. Forty-four returning participants (62 eyes) had undergone incident cataract surgery, an incidence of 4.84% (95% confidence interval [CI] = [3.53, 6.44]). Detailed medical and surgical records were available for 54/62 (87.1%) eyes, and of these, 5/54 (24.1%) had an immediate preoperative visual acuity ≤ 6/120. All recorded surgeries were performed at tertiary-level hospitals with phacoemulsification and foldable intraocular lens implantation. Those undergoing cataract surgery were more educated (P < 0.05) and had poorer baseline PVA in the worse-seeing eye (P < 0.001) than 54 persons with baseline PVA <6/18 due to cataract who had not had surgery. Among the 62 operated eyes, 22.6% (14/62) had PVI based on PVA and 9.6% (6/62) based on BCVA., Conclusions: Despite somewhat lower incidence, outcomes of cataract surgery in urban southern China are comparable with developed countries and better than for rural China. In urban China, emphasis should be on improving access to surgery.
- Published
- 2012
- Full Text
- View/download PDF
21. Early assessment of visual acuity after cataract surgery in rural Indonesia.
- Author
-
Bani A, Wang D, and Congdon N
- Subjects
- Aged, Eyeglasses statistics & numerical data, Female, Follow-Up Studies, Humans, Indonesia epidemiology, Lenses, Intraocular, Male, Middle Aged, Patient Acceptance of Health Care statistics & numerical data, Prospective Studies, Cataract Extraction statistics & numerical data, Lens Implantation, Intraocular, Pseudophakia physiopathology, Rural Population statistics & numerical data, Visual Acuity physiology
- Abstract
Background: The accuracy and impact on service uptake of early examination after cataract surgery is not known., Design: Prospective cohort study., Participants: Cataract patients in rural Indonesia., Methods: Visual acuity was measured preoperatively, 1day, 1-3, 4-6 and >12weeks after surgery, and 6-8months postoperatively at an outreach examination. Acceptance of second-eye surgery and spectacles was evaluated., Main Outcome Measure: Presenting visual acuity in the operated eye., Results: Among 241 subjects (extracapsular surgery 84%), examinations at 1day, 1-3, 4-6 and >12weeks and 6-8months were completed for 100% (241), 90.9% (219), 67.6% (163), 22.0% (53) and 80.0% (193), respectively. Among subjects at the final examination (mean age 65.8±10.6years, 51.8% male), 73.6% had bilateral preoperative presenting visual acuity≤6/60. By 4-6weeks, the proportion with good (≥6/18) or poor (≤6/60) visual acuity did not differ significantly from the final examination. Among 49 persons accepting free second-eye surgery, 69.4% (34) and 16.3% (8) returned to clinic at 4-6 and >12weeks, respectively. Among 131 patients (67.9%) paying US$7 for glasses, 94 (71.8%) and 30 (22.9%) attended 4- to 6- and >12-week examinations, respectively., Conclusion: Even with large-incision surgery, early assessment of postoperative vision is representative of final vision, and may help deliver postoperative services to more of those needing them., (© 2011 The Authors. Clinical and Experimental Ophthalmology © 2011 Royal Australian and New Zealand College of Ophthalmologists.)
- Published
- 2012
- Full Text
- View/download PDF
22. Cataract surgical outcomes, visual function and quality of life in four rural districts in Vietnam.
- Author
-
Yuen L, Do NH, Vu QL, Gupta S, Ambrosio E, and Congdon N
- Subjects
- Aged, Aged, 80 and over, Cross-Sectional Studies, Female, Humans, Intraoperative Complications, Lens Implantation, Intraocular statistics & numerical data, Male, Middle Aged, Patient Satisfaction, Treatment Outcome, Vietnam epidemiology, Cataract epidemiology, Cataract Extraction statistics & numerical data, Quality of Life, Rural Population statistics & numerical data, Visual Acuity physiology
- Abstract
Background: To evaluate cataract surgical outcomes in four rural districts of Ha Tinh Province, Vietnam., Design: Cross-sectional study., Participants: Post-cataract surgery patients sampled randomly from facilities in four rural districts of Ha Tinh Province >3 months after surgery., Main Outcome Measures: Postoperative visual acuity (VA), visual function and quality of life., Results: Among 412 patients, the mean age was 74.5 ± 9.4 years, 67% (276) were female, and 377 (91.5%) received intraocular lenses (IOL). Nearly two-thirds of patients had no postoperative visits after discharge. Postoperatively, more than 40% of eyes had presenting VA <6/18, while 20% remained <6/60. The mean self-reported visual function and quality of life for all patients were 68.7 ± 23.8 and 73.8 ± 21.6, respectively. Most patients (89.5%) were satisfied with surgery and the majority (94.4%) would recommend surgery to others. One-third of patients paid ≥$US50 for surgery. In multiple regression modelling, older age (P < 0.01), intraoperative complications (P < 0.01) and failure to receive an IOL (P < 0.01) were associated with postoperative VA <6/60., Conclusion: Satisfaction with surgery was high, and many patients were willing to pay for their operations. Poor visual outcomes were common; however, and better surgical training is needed to reduce complications and their impact on visual outcomes. More intensive postoperative follow-up may also be beneficial., (© 2011 The Authors. Clinical and Experimental Ophthalmology © 2011 Royal Australian and New Zealand College of Ophthalmologists.)
- Published
- 2011
- Full Text
- View/download PDF
23. The association between refractive cutoffs for spectacle provision and visual improvement among school-aged children in South Africa.
- Author
-
Congdon NG, Patel N, Esteso P, Chikwembani F, Webber F, Msithini RB, and Ratcliffe A
- Subjects
- Adolescent, Adult, Child, Clinical Protocols, Female, Humans, Male, Patient Compliance statistics & numerical data, Program Evaluation, Prospective Studies, Rural Health statistics & numerical data, Urban Health statistics & numerical data, Vision Screening methods, Eyeglasses statistics & numerical data, Refraction, Ocular, Refractive Errors physiopathology, Refractive Errors therapy, Visual Acuity
- Abstract
Objectives: To evaluate different refractive cutoffs for spectacle provision with regards to their impact on visual improvement and spectacle compliance., Design: Prospective study of visual improvement and spectacle compliance., Participants: South African school children aged 6-19 years receiving free spectacles in a programme supported by Helen Keller International., Methods: Refractive error, age, gender, urban versus rural residence, presenting and best-corrected vision were recorded for participants. Spectacle wear was observed directly at an unannounced follow-up examination 4-11 months after initial provision of spectacles. The association between five proposed refractive cutoff protocols and visual improvement and spectacle compliance were examined in separate multivariate models., Main Outcomes: Refractive cutoffs for spectacle distribution which would effectively identify children with improved vision, and those more likely to comply with spectacle wear., Results: Among 8520 children screened, 810 (9.5%) received spectacles, of whom 636 (79%) were aged 10-14 years, 530 (65%) were girls, 324 (40%) had vision improvement > or = 3 lines, and 483 (60%) were examined 6.4+/-1.5 (range 4.6 to 10.9) months after spectacle dispensing. Among examined children, 149 (31%) were wearing or carrying their glasses. Children meeting cutoffs < or = -0.75 D of myopia, > or = +1.00 D of hyperopia and > or = +0.75 D of astigmatism had significantly greater improvement in vision than children failing to meet these criteria, when adjusting for age, gender and urban versus rural residence. None of the proposed refractive protocols discriminated between children wearing and not wearing spectacles. Presenting vision and improvement in vision were unassociated with subsequent spectacle wear, but girls (p < or = 0.0006 for all models) were more likely to be wearing glasses than were boys., Conclusions: To the best of our knowledge, this is the first suggested refractive cutoff for glasses dispensing validated with respect to key programme outcomes. The lack of association between spectacle retention and either refractive error or vision may have been due to the relatively modest degree of refractive error in this African population.
- Published
- 2008
- Full Text
- View/download PDF
24. Distribution and visual impact of postoperative refractive error after cataract surgery in rural China: study of cataract outcomes and up-take of services report 4.
- Author
-
Zhou Z, Congdon NG, Zhang M, Chen L, Zheng Z, Zhang L, Lin X, He L, Choi K, and Lam DS
- Subjects
- Aged, Biometry, China epidemiology, Female, Humans, Lens Implantation, Intraocular, Male, Models, Statistical, Outcome and Process Assessment, Health Care, Refraction, Ocular, Rural Population statistics & numerical data, Treatment Outcome, Cataract Extraction, Hyperopia physiopathology, Lenses, Intraocular, Myopia physiopathology, Postoperative Complications, Visual Acuity physiology
- Abstract
Purpose: To model the possible impact of using average-power intraocular lenses (IOLs) and evaluate the postoperative refractive error in patients having cataract surgery in rural China., Setting: Rural Guangdong, China., Methods: Patients having cataract surgery by local surgeons were examined and visual function was assessed 10 to 14 months after surgery. Subjective refraction at near and distance was performed bilaterally by an ophthalmologist. Patients had a target refraction of -0.50 diopter (D) based on ocular biometry., Results: Of the 313 eligible patients, 242 (77%) could be contacted and 176 (74% of contacted patients, 56% overall) were examined. Examined patients had a mean age of 69.4 +/- 10.5 years. Of the 211 operated eyes, 73.2% were within +/-1.0 D of the target refraction after surgery. The best presenting distance vision was in patients within +/-1.0 D of plano and the best presenting near vision, in those with mild myopia (<-1.0 D to > or =2.0 D) (P= .005). However, patients with hyperopia (>+1.0 D) reported significantly better adjusted visual function than those with emmetropia or myopia (<-1.0 D). When the predicted use of an average-power IOL (median +21.5 D) was modeled, predicted visual acuity was significantly reduced (P= .001); however, predicted visual function was not significantly altered (P>.3)., Conclusions: Accurate selection of postoperative refractive error was achieved by local surgeons in this rural area. Based on visual function results, aiming for mild postoperative myopia may not be suitable in this setting. Implanting average-power IOLs significantly reduced postoperative presenting vision, but not visual function.
- Published
- 2007
- Full Text
- View/download PDF
25. Visual outcomes and astigmatism after sutureless, manual cataract extraction in rural China: study of cataract outcomes and up-take of services (SCOUTS) in the caring is hip project, report 1.
- Author
-
Lam DS, Congdon NG, Rao SK, Fan H, Liu Y, Zhang L, Lin X, Choi K, Zheng Z, Huang W, Zhou Z, and Pang CP
- Subjects
- Aged, Cataract Extraction education, China epidemiology, Clinical Competence, Female, Humans, Lens Implantation, Intraocular, Male, Ophthalmology education, Postoperative Period, Refraction, Ocular, Treatment Outcome, Astigmatism epidemiology, Cataract Extraction statistics & numerical data, Rural Population statistics & numerical data, Suture Techniques, Visual Acuity physiology
- Abstract
Objective: To study the visual acuity and astigmatism of persons undergoing cataract extraction by local surgeons in rural China., Methods: Visual acuity, keratometry, and refraction were measured 10 to 14 months postoperatively for all cataract cases during 4 months in Sanrao, China., Results: Among 313 eligible subjects, 242 (77%) could be contacted, of whom 176 (73%) were examined. Of those who were examined, mean +/- SD age was 69.3 +/- 10.5 years, 66.5% were female, 35 had been operated on bilaterally at Sanrao, and 85.2% had a preoperative presenting visual acuity of 6/60 or worse. Presenting and best-corrected postoperative acuity in the eye that was operated on were 6/18 or better in 83.4% and 95.7%, respectively. Among 27 fellow eyes operated on elsewhere, 40.7% had a presenting acuity of 6/18 or better and 40.7% were blind (P < .001). Mean +/- SD postoperative astigmatism did not differ between 211 eyes that were operated on (-1.13 +/- 0.84 diopters) and 109 eyes that were not (-1.13 +/- 1.17 diopters; P = .27). Presence of operative complications (8.5%) and older age were associated with worse vision; bilateral surgery was associated with better vision., Conclusions: These results confirm the effectiveness of skill transfer in this setting, with superior outcomes to most studies in rural Asia and to eyes in this cohort operated on at other facilities.
- Published
- 2007
- Full Text
- View/download PDF
26. Visual function and postoperative care after cataract surgery in rural China: study of cataract outcomes and up-take of services (SCOUTS) in the caring is hip project, report 2.
- Author
-
Congdon NG, Rao SK, Zhao X, Wang W, Choi K, and Lam DS
- Subjects
- Aged, China epidemiology, Female, Health Services statistics & numerical data, Humans, Lens Implantation, Intraocular, Male, Refraction, Ocular, Surveys and Questionnaires, Treatment Outcome, Cataract Extraction statistics & numerical data, Postoperative Care, Rural Population statistics & numerical data, Visual Acuity physiology
- Abstract
Objective: To study the postoperative visual function and uptake of refraction and second-eye surgery among persons undergoing cataract surgery in rural China., Methods: Self-reported visual function was measured 10 to 14 months after surgery. Subjects with improvement of 2 or more lines with refraction were offered glasses, and those with significant cataract were offered second-eye surgery., Results: Among 313 eligible subjects, 242 (77%) could be contacted; 176 (73%) of those contacted were examined. Interviewed subjects had a mean +/- SD age of 69.9 +/- 10.2 years, and 63.6% were female. The mean +/- SD visual function score was 88.4 +/- 12.3, higher than previously reported for cataract programs in rural China and significantly (P = .03) correlated with presenting vision. Forty-two percent of subjects had spectacles, more than half being reading glasses. Though 87% of subjects' vision improved with refraction, only 35% accepted prescriptions, the most common reason for refusal being lack of perceived need. Second-eye surgery was accepted by a total of 48% (85 of 176) of patients, cost being the biggest reason for refusal., Conclusions: Visual function was high in this cohort. Potential benefit of refraction and second-eye surgery was substantial, but uptake of services was modest. Programs to improve service uptake should focus on reading glasses and cost-reduction strategies such as tiered pricing.
- Published
- 2007
- Full Text
- View/download PDF
27. Correction of moderate myopia is associated with improvement in self-reported visual functioning among Mexican school-aged children.
- Author
-
Esteso P, Castanon A, Toledo S, Rito MA, Ervin A, Wojciechowski R, and Congdon NG
- Subjects
- Child, Female, Follow-Up Studies, Humans, Male, Mexico, Rural Population, Self Disclosure, Vision Disorders physiopathology, Vision Disorders therapy, Eyeglasses, Myopia physiopathology, Myopia therapy, Visual Acuity physiology, Visual Perception physiology
- Abstract
Purpose: To quantify the impact on self-reported visual functioning of spectacle provision for school-aged children in Oaxaca, Mexico., Methods: The Refractive Status Vision Profile (RSVP), a previously validated tool to measure the impact of refractive correction on visual functioning, was adapted for use in rural children and administered at baseline and 4 weeks (27.3 +/- 4.4 days) after the provision of free spectacles. Visual acuity with and without correction, age, sex, and spherical equivalent refraction were recorded at the time of follow-up., Results: Among 88 children (mean age, 12 years; 55.7% girls), the median presenting acuity (uncorrected or with original spectacles), tested 4 weeks after the provision of free spectacles, was 6/9 (range, 6/6-6/120). Significant improvements in the following subscales of the RSVP were seen for the group as a whole after the provision of free spectacles: function, 11.2 points (P = 0.0001); symptoms, 14.3 points (P < 0.0001); total score, 10.3 points (P = 0.0001). After stratification by presenting vision in the better-seeing eye, children with 6/6 acuity (n = 22) did not have significant improvement in any subscale; those with acuity of 6/7.5 to 6/9 (n = 34) improved only on function (P = 0.02), symptoms (P = 0.005), and total score (P = 0.003); and those with acuity of 6/12 or worse improved on total score (P < 0.0001) and all subscales. Subjects (n = 31) with uncorrected myopia of -1.25 D or more had a mean improvement in total score of 15.9 points (P < 0.0001), whereas those with uncorrected myopia between -0.50 and -1.00 D inclusive (n = 53) had a mean improvement of 8 points (P = 0.01)., Conclusions: Provision of spectacles to children in this setting had a significant impact on self-reported function, even at modest levels of baseline visual disability. The correlation between presenting vision/refraction and improvement and the failure of children 6/6 at baseline to improve offer evidence for a real effect.
- Published
- 2007
- Full Text
- View/download PDF
28. Impact of primary glaucoma on health-related quality of life in China: the handan eye study.
- Author
-
Song, Di, Fan, Sujie, Zhou, Qiang, Yang, Xiaohui, Li, Sizhen, Lohfeld, Lynne, Zhou, Weihe, Congdon, Nathan, Liang, Yuanbo, and Wang, Ningli
- Subjects
QUALITY of life ,ANGLE-closure glaucoma ,GLAUCOMA ,OPEN-angle glaucoma ,VISUAL acuity - Abstract
Background: We assessed health-related quality of life (HRQOL) and its determinants among rural glaucoma participants compared to age-matched normal controls in the population-based Handan Eye Study (HES), in rural Yongnian County, northern China. Methods: We enrolled 99 adults with glaucoma (mean age 63.0 ± 11.0 years), including primary open-angle glaucoma (POAG, n = 67) and primary angle-closure glaucoma (PACG, n = 32) and 102 controls (mean age 58.5 ± 5.3 years) with normal visual acuity and visual field and no history of glaucoma. Results of ophthalmic examinations and socioeconomic data were recorded. HRQOL was measured using the EQ-5D (converted to utility valves, UVs), and visual function (VF) and vision-related quality of life (VRQOL) were evaluated using the visual function-quality of life (VF-QOL) instrument. Primary and secondary outcome measures: EQ-5D and VF-QOL scores. Results: The mean UVs, VF, and VRQOL scores for glaucoma cases were 0.98 ± 0.04, 87.9 ± 15.2, and 95.5 ± 12.8, respectively, significantly worse than VF (94.4 ± 4.4) and VRQOL (100.0 ± 0.0) among controls, even after adjusting for age, gender, educational level, and family income (P = 0.015, P = 0.033). UVs were significantly lower among glaucoma participants with impaired VRQOL (55.4 ± 11.5) compared to those with normal VRQOL scores (99.1 ± 2.8) (UVs: 0.92 ± 0.08 vs. 0.99 ± 0.03, P = 0.036), also after adjustment for age and family income (P = 0.006). Participants with PACG had significantly lower VF and VRQOL scores compared to POAG (77.8 ± 21.4 vs. 92.9 ± 6.8, P < 0.001; 89.0 ± 18.1 vs. 98.7 ± 7.5, P < 0.001). Conclusion: Participants with glaucoma have worse visual function and related quality of life compared to age-matched normal population controls. Participants with PACG have lower VF and VRQOL compared to those with POAG. UVs can be used for cost-effectiveness research and to support public health strategies for glaucoma in rural China. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
29. Self correction of refractive error among young people in rural China: results of cross sectional investigation
- Author
-
Zhang, Mingzhi, Zhang, Riping, He, Mingguang, Liang, Wanling, Li, Xiaofeng, She, Lingbing, Yang, Yunli, MacKenzie, Graeme, Silver, Joshua D, Ellwein, Leon, Moore, Bruce, and Congdon, Nathan
- Published
- 2011
30. Falls and Physical Activity among Cataract Patients in Vietnam.
- Author
-
To, Quyen, Huynh, Van-Anh, Do, Dung, Do, Vu, Congdon, Nathan, Meuleners, Lynn, Vandelanotte, Corneel, Hong, Hiep, Nguyen, Ho, and To, Kien
- Subjects
INTRAOCULAR lenses ,PHYSICAL activity ,CONTRAST sensitivity (Vision) ,VISUAL acuity ,CATARACT ,FIFTH grade (Education) - Abstract
To investigate the relationship between falls, physical activity, and other socio-demographic and visual factors among cataract patients in Ho Chi Minh City, Vietnam. A cross-sectional study was conducted between April and November 2018. Patients presenting to two hospitals with age-related unilateral or bilateral cataract, aged ≥50 years, literate, and scheduled for a first-eye cataract surgery were recruited. The International Physical Activity Questionnaires short form was used to measure physical activity. Visual disability score was self-reported using the Catquest-9SF. The number of falls in the last 12 months prior to data collection were self-reported. Visual acuity and contrast sensitivity were measured using standard protocols. A total of 340 patients had complete data, the majority of whom were women (62.4%), living with a spouse (66.5%), had an education level of Grade 5 or below (68.2%), and a monthly income from medium to high (58.5%). Average age was 65.7 years. A total of 135 falls were reported in the last 12 months with 27.6% reporting ≥1 fall and 7.1% ≥2 falls. Persons with high (adjusted Prevalence Ratio (aPR) = 2.4, 95%CI = 1.2, 4.7) and low (aPR = 2.4, 95%CI = 1.2, 4.6) physical activity levels had more falls compared to those with moderate levels. Women (aPR = 1.7, 95%CI = 1.04, 2.7) and those with medium income (aPR = 2.9, 95%CI = 1.2, 6.9) were more likely to fall. Poor binocular logMAR visual acuity with habitual correction (aPR = 2.3, 95%CI = 1.1, 4.6) and poor visual disability scores (aPR = 1.4, 95%CI = 1.02, 2.0) were associated with falling. Patients with a moderate level of physical activity were less likely to fall compared to those with low or high levels although this U-shape relationship needs to be further investigated in prospective interventional trials. Men and those with high monthly income, better visual acuity and visual disability score were also less likely to fall. Cataract patients might be advised to maintain a moderate level of physical activity while waiting for surgery. Strategies to prevent falls may also prioritise cataract surgery for women and those with lower income. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
31. The impact of distance cataract surgical wet laboratory training on cataract surgical competency of ophthalmology residents.
- Author
-
Geary, Amelia, Wen, Qing, Adrianzén, Rosa, Congdon, Nathan, Janani, R., Haddad, Danny, Timbo, Clare Szalay, and Khalifa, Yousuf M.
- Subjects
PHACOEMULSIFICATION ,COVID-19 pandemic ,CATARACT ,TRAINING of medical residents ,OPHTHALMOLOGY ,VISUAL acuity - Abstract
Background: This study assessed the impact of distance cataract surgical wet laboratory training on surgical competency of ophthalmology residents at a tertiary-level ophthalmic training center in Trujillo, Peru. Methods: Three five-week distance wet lab courses were administered through Cybersight, Orbis International's telemedicine platform. Weekly lectures and demonstrations addressed specific steps in phacoemulsification surgery. Each lecture had two accompanying wet lab assignments, which residents completed and recorded in their institution's wet lab and uploaded to Cybersight for grading. Competency was assessed through anonymous grading of pre- and post-training surgical simulation videos, masked as to which occurred before and after training, using a standardized competency rubric adapted from the Ophthalmology Surgical Competency Assessment Rubric (OSCAR, scale of 0–32). Day one best-corrected post-operative visual acuity (BVCA) was assessed in the operative eye on the initial consecutive 4–6 surgeries conducted by the residents as per the norms of their residency training. An anonymous post-training satisfaction survey was administered to trainees'. Results: In total, 21 ophthalmic residents participated in the courses, submitting a total of 210 surgical videos. Trainees' average competency score increased 6.95 points (95%CI [4.28, 9.62], SD = 5.01, p < 0.0001, two sample t-test) from 19.3 (95%CI [17.2, 21.5], SD = 4.04) to 26.3 (95%CI [24.2, 28.3], SD = 3.93). Visual acuity for 92% of post-training resident surgeries (n = 100) was ≥20/60, meeting the World Health Organization's criterion for good quality. Conclusions: Structured distance wet lab courses in phacoemulsification resulted in significantly improved cataract surgical skills. This model could be applicable to locations where there are obstacles to traditional in-person training, such as the current COVID-19 pandemic. [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
- View/download PDF
32. Rapid assessment of avoidable blindness and cataract surgery coverage among forcibly displaced Myanmar Nationals (Rohingya refugees) in Cox's Bazar, Bangladesh.
- Author
-
Hussain, A. H. M. Enayet, Ahmed, Munir, Vincent, Jerry E., Islam, Johurul, Sapkota, Yuddha D., Das, Taraprasad, Congdon, Nathan, Husain, Lutful, Khandaker, Gulam, Muhit, Mohammad, Hossain, Mohammad Awlad, and Haddad, Danny
- Subjects
CATARACT surgery ,BLINDNESS ,REFRACTIVE errors ,VISION disorders ,VISUAL acuity ,CATARACT ,LOW vision ,INTRAOCULAR lenses - Abstract
Aim: To determine the prevalence and causes of blindness, vision impairment and cataract surgery coverage among Rohingya refugees aged ≥ 50 years residing in camps in Cox's Bazar, Bangladesh. Methods: We used the Rapid Assessment of Avoidable Blindness (RAAB) methodology to select 76 clusters of 50 participants aged ≥ 50 years with probability proportionate to size. Demographic and cataract surgery data were collected using questionnaires, visual acuity was assessed per World Health Organization criteria and examinations were conducted by torch, and with direct ophthalmoscopy in eyes with pinhole-corrected vision <6/12. RAAB software was used for data entry and analysis. Results: We examined 3,629 of 3800 selected persons (95.5%). Age and sex adjusted prevalence of blindness (<3/60), severe visual impairment (SVI; >3/60 to ≤6/60), moderate visual impairment (MVI; >6/60 to ≤6/18), and early visual impairment (EVI; >6/18 to ≤6/12) were 2.14%, 2.35%, 9.68% and 14.7% respectively. Cataract was responsible for 75.0% of blindness and 75.8% of SVI, while refractive error caused 47.9% and 90.9% of MVI and EVI respectively. Most vision loss (95.9%) was avoidable. Cataract surgical coverage among the blind was 81.2%. Refractive error was detected in 17.1% (n = 622) of participants and 95.2% (n = 592) of these did not have spectacles. In the full Rohingya cohort of 76,692, approximately 10,000 surgeries are needed to correct all eyes impaired (<6/18) by cataract, 12,000 need distance glasses and 73,000 require presbyopic correction. Conclusion: The prevalence of blindness was lower than expected for a displaced population, in part due to few Rohingya being ≥60 years and the camp's good access to cataract surgery. We suggest the United Nations High Commissioner for Refugees include eye care among recommended health services for all refugees with long-term displacement. [ABSTRACT FROM AUTHOR]
- Published
- 2020
- Full Text
- View/download PDF
33. Influence of presbyopia on smartphone usage among Chinese adults: A population study.
- Author
-
Wang, Congyao, Wang, Xiuqin, Jin, Ling, Tang, Bobby, Zhu, Wenhui, Zhang, Guoshan, Chen, Tingting, McAneney, Helen, Kassalow, Jordan, and Congdon, Nathan
- Subjects
PRESBYOPIA ,VISION disorders ,VISUAL acuity ,OLDER people ,LOGISTIC regression analysis - Abstract
Importance: Presbyopia, an essentially universal, age‐related loss of the ability to focus un‐aided on near objects, is the world's leading cause of visual impairment. Background: Smartphone use is widespread in China, but little is known about the prevalence, determinants and correction of difficulties with smartphone use in the setting of presbyopia. Design: Cross‐sectional data from a population‐based longitudinal cohort study. Participants: A total of 1817 persons aged ≥35 years in Guangzhou, Southern China. Methods: Participants underwent near visual acuity (NVA) testing and completed questionnaires on smartphone usage detailing knowledge of their own presbyopia status, frequency (hours/day) and subjective difficulties with use of mobile and smartphones. Presbyopia was defined as uncorrected bilateral NVA ≤6/12 with best‐corrected bilateral NVA >6/12. Main Outcome Measures: Difficulty in smartphone use associated with uncorrected presbyopia. Results: Among 1427 respondents (78.5%) undergoing examination, 1191 (83.5%) completed questionnaires (mean age 52.3 ± 11.6 years; 54.9% women). Among 451 persons (37.8%) with presbyopia owning smartphones, 290 (64.3%) reported difficulty using them. Multiple ordinal logistic regression modelling showed difficulty in smartphone use due to presbyopia was associated with higher educational level (P = .013), worse NVA (P < .001) and more time spent using smartphones (P = .002 for 1‐3 hours/day). Among persons with presbyopia owning smartphones, 353 (78.0%) said they would pay >US$15 (median US$45) for innovations making smartphone use easier. Conclusions and Relevance: Difficulty in using smartphones in the presence of presbyopia is common and affected persons are willing to pay for useful solutions to the problem. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
34. Teachers' influence on purchase and wear of children's glasses in rural China: The PRICE study.
- Author
-
Wang, Xiuqin, Ma, Yue, Hu, Min, Jin, Ling, Xiao, Baixiang, Ni, Ming, Yi, Hongmei, Ma, Xiaochen, Wang, Congyao, Varga, Beatrice, Huang, Yiwen, Rozelle, Scott, and Congdon, Nathan
- Subjects
TEACHER influence ,CHILDHOOD attitudes ,CHINA studies ,VISUAL acuity ,CHILDREN - Abstract
Importance: Uncorrected refractive error causes 90% of poor vision among Chinese children. Background: Little is known about teachers' influence on children's glasses wear. Design: Cohort study. Participants: Children at 138 randomly selected primary schools in Guangdong and Yunnan provinces, China, with uncorrected visual acuity (VA) ≤6/12 in either eye correctable to >6/12 in both eyes, and their teachers. Methods: Teachers and children underwent VA testing and completed questionnaires about spectacles use and attitudes towards children's vision. Main Outcome Measures: Children's acceptance of free glasses, spectacle purchase and wear. Results: A total of 882 children (mean age 10.6 years, 45.5% boys) and 276 teachers (mean age 37.9 years, 67.8% female) participated. Among teachers, 20.4% (56/275) believed glasses worsened children's vision, 68.4% (188/275) felt eye exercises prevented myopia, 55.0% (151/275) thought children with modest myopia should not wear glasses and 93.1% (256/275) encouraged children to obtain glasses. Teacher factors associated with children's glasses‐related behaviour included believing glasses harm children's vision (decreased purchase, univariate model: relative risk [RR] 0.65, 95% CI 0.43, 0.98, P < 0.05); supporting children's classroom glasses wear (increased glasses wear, univariate model: RR 2.20, 95% CI 1.23, 3.95, P < 0.01); and advising children to obtain glasses (increased free glasses acceptance, multivariate model: RR 2.74, 95% CI 1.29, 5.84, P < 0.01; increased wear, univariate model: RR 2.93, 95% CI 1.45, 5.90, P < 0.01), but not teacher's ownership/wear of glasses. Conclusions and Relevance: Though teachers had limited knowledge about children's vision, they influenced children's glasses acceptance. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
35. Self-refraction, ready-made glasses and quality of life among rural myopic Chinese children: a non-inferiority randomized trial.
- Author
-
Zhou, Zhongqiang, Chen, Tingting, Jin, Ling, Zheng, Dongxing, Chen, Shangji, He, Mingguang, Silver, Josh, Ellwein, Leon, Moore, Bruce, and Congdon, Nathan G.
- Subjects
MYOPIA ,QUALITY of life ,CHILDREN ,REFRACTIVE errors ,EYEGLASSES ,VISUAL acuity ,ASTIGMATISM ,PATIENTS - Abstract
Purpose To study, for the first time, the effect of wearing ready-made glasses and glasses with power determined by self-refraction on children's quality of life. Methods This is a randomized, double-masked non-inferiority trial. Children in grades 7 and 8 (age 12-15 years) in nine Chinese secondary schools, with presenting visual acuity ( VA) ≤6/12 improved with refraction to ≥6/7.5 bilaterally, refractive error ≤−1.0 D and <2.0 D of anisometropia and astigmatism bilaterally, were randomized to receive ready-made spectacles ( RM) or identical-appearing spectacles with power determined by: subjective cycloplegic retinoscopy by a university optometrist (U), a rural refractionist (R) or non-cycloplegic self-refraction ( SR). Main study outcome was global score on the National Eye Institute Refractive Error Quality of Life-42 ( NEI- RQL-42) after 2 months of wearing study glasses, comparing other groups with the U group, adjusting for baseline score. Results Only one child (0.18%) was excluded for anisometropia or astigmatism. A total of 426 eligible subjects (mean age 14.2 years, 84.5% without glasses at baseline) were allocated to U [103 (24.2%)], RM [113 (26.5%)], R [108 (25.4%)] and SR [102 (23.9%)] groups, respectively. Baseline and endline score data were available for 398 (93.4%) of subjects. In multiple regression models adjusting for baseline score, older age (p = 0.003) and baseline spectacle wear (p = 0.016), but not study group assignment, were significantly associated with lower final score. Conclusion Quality of life wearing ready-mades or glasses based on self-refraction did not differ from that with cycloplegic refraction by an experienced optometrist in this non-inferiority trial [ABSTRACT FROM AUTHOR]
- Published
- 2017
- Full Text
- View/download PDF
36. Phacoemulsification combined with posterior capsulorhexis and anterior vitrectomy in the management of malignant glaucoma in phakic eyes.
- Author
-
Liu, Xing, Li, Mei, Cheng, Bing, Mao, Zhen, Zhong, Yimin, Wang, Dandan, Cao, Dan, Yu, Fenfen, and Congdon, Nathan G.
- Subjects
ANGLE-closure glaucoma ,INTRAOCULAR lenses ,PHACOEMULSIFICATION ,VITRECTOMY ,ARTIFICIAL implants ,VISUAL acuity ,ANTERIOR chamber (Eye) - Abstract
. Purpose: To describe sequential phacoemulsification-intraocular lens (IOL) implantation-posterior capsulorhexis-anterior vitrectomy in the management of phakic malignant glaucoma. Methods: Twenty consecutive patients (25 eyes) with phakic malignant glaucoma were enrolled at the Zhongshan Ophthalmic Center, Sun Yat-sen University. All patients underwent phacoemulsification, IOL implantation and posterior capsulorhexis together with anterior vitrectomy via a clear corneal paracentesis. Visual acuity, intraocular pressure (IOP), anterior chamber depth (ACD), surgical complications and medications required after the surgery were recorded. Results: After surgery, the mean LogMAR visual acuity and ACD increased significantly (visual acuity from −1.56 ± 1.17 to −0.54 ± 0.81, p < 0.001; ACD from 0.367 ± 0.397 mm to 2.390 ± 0.575 mm, p < 0.001), and mean IOP decreased significantly (from 39.6 ± 10.6 mm Hg to 14.5 ± 4.1 mmHg, p < 0.001). No serious perioperative complications occurred, and only five eyes required topical glaucoma medications after surgery. Conclusion: Combined phacoemulsification-IOL implantation-posterior capsulorhexis-anterior vitrectomy surgery is a safe and effective method for treating patients with phakic malignant glaucoma. [ABSTRACT FROM AUTHOR]
- Published
- 2013
- Full Text
- View/download PDF
37. Visual Symptoms and Retinal Straylight after Laser Peripheral Iridotomy: The Zhongshan Angle-Closure Prevention Trial
- Author
-
Congdon, Nathan, Yan, Xixi, Friedman, David S., Foster, Paul J., van den Berg, Thomas J.T.P., Peng, Michelle, Gangwani, Rita, and He, Mingguang
- Subjects
- *
GLAUCOMA treatment , *CATARACT , *SYMPTOMS , *VISUAL acuity , *DISEASE prevalence , *RETINAL (Visual pigment) ,GLAUCOMA surgery - Abstract
Objective: To assess the impact of laser peripheral iridotomy (LPI) on forward-scatter of light and subjective visual symptoms and to identify LPI parameters influencing these phenomena. Design: Cohort study derived from a randomized trial, using an external control group. Participants: Chinese subjects initially aged 50 or older and 70 years or younger with bilateral narrow angles undergoing LPI in 1 eye selected at random, and age- and gender-matched controls. Methods: Eighteen months after laser, LPI-treated subjects underwent digital iris photography and photogrammetry to characterize the size and location of the LPI, Lens Opacity Classification System III cataract grading, and measurement of retinal straylight (C-Quant; OCULUS, Wetzlar, Germany) in the treated and untreated eyes and completed a visual symptoms questionnaire. Controls answered the questionnaire and underwent straylight measurement and (in a random one-sixth sample) cataract grading. Main Outcome Measures: Retinal straylight levels and subjective visual symptoms. Results: Among 230 LPI-treated subjects (121 [58.8%] with LPI totally covered by the lid, 43 [19.8%] with LPI partly covered by the lid, 53 [24.4%] with LPI uncovered by the lid), 217 (94.3%) completed all testing, as did 250 (93.3%) of 268 controls. Age, gender, and prevalence of visual symptoms did not differ between treated subjects and controls, although nuclear (P<0.01) and cortical (P = 0.03) cataract were less common among controls. Neither presenting visual acuity nor straylight score differed between the treated and untreated eyes among all treated persons, nor among those (n = 96) with LPI partially or totally uncovered. Prevalence of subjective glare did not differ significantly between participants with totally covered LPI (6.61%; 95% confidence interval [CI], 3.39%–12.5%), partially covered LPI (11.6%; 95% CI, 5.07%–24.5%), or totally uncovered LPI (9.43%; 95% CI, 4.10%–10.3%). In regression models, only worse cortical cataract grade (P = 0.01) was associated significantly with straylight score, and no predictors were associated with subjective glare. None of the LPI size or location parameters were associated with straylight or subjective symptoms. Conclusions: These results suggests that LPI is safe regarding measures of straylight and visual symptoms. This randomized design provides strong evidence that treatment programs for narrow angles would be unlikely to result in important medium-term visual disability. Financial Disclosure(s): Proprietary or commercial disclosure may be found after the references. [Copyright &y& Elsevier]
- Published
- 2012
- Full Text
- View/download PDF
38. Willingness to pay for potential enhancements to a low-cost cataract surgical package in rural southern China.
- Author
-
Ko, Fang, Frick, Kevin D., Tzu, Jonathan, He, Mingguang, and Congdon, Nathan
- Subjects
CRYSTALLINE lens diseases ,CATARACT ,VISUAL acuity ,OPHTHALMIC surgery - Abstract
. Purpose: To assess determinants of patients' willingness to pay (WTP) for potential components of a multi-tiered cataract surgical package offered by a non-governmental organization (NGO) in rural China. Design: Cross-sectional study. Methods: Demographic and clinical data were collected from 505 patients presenting for cataract screening or surgery in Yangjiang, China. Willingness to pay for potential enhancements to the current surgery package was assessed using a bidding format with random payment cards. Results: Among 426 subjects (84.4%) completing interviews, the mean age was 73.9 ± 7.3 years, 67.6% were women and 73% ( n = 310) would pay for at least one offering, with 33-38% WTP for each item. Among those who would pay, the mean WTP for food was US$1.68 ± 0.13, transportation US$3.24 ± 0.25, senior surgeon US$50.0 ± 3.36 and US$89.4 ± 4.19 for an imported intra-ocular lens (IOL). The estimated total recovery from these enhancements under various assumptions would be US$20-50 (compared to the current programme price of US$65). In multivariate models, WTP for the senior surgeon increased with knowledge of a person previously operated for cataract (OR = 2.13, 95% CI 1.42-3.18, p < 0.001). Willingness to pay for the imported IOL increased with knowledge of a previously operated person (OR = 1.85, 95% CI 1.24-2.75, p < 0.01) and decreased with age >75 years (OR = 0.61, 0.40-0.93, p < 0.05). Conclusions: Opportunities exist to increase cataract programme revenues through multi-tiered offerings in this setting, allowing greater subsidization of low-income patients. Personal familiarity with cataract surgery is important in determining WTP. [ABSTRACT FROM AUTHOR]
- Published
- 2012
- Full Text
- View/download PDF
39. Randomized, Controlled Trial of an Educational Intervention to Promote Spectacle Use in Rural China: The See Well to Learn Well Study
- Author
-
Congdon, Nathan, Li, Liping, Zhang, Mingzhi, Yang, Amy, Gao, Yang, Griffiths, Sian, Wu, Jiasi, Sharma, Abhishek, and Lam, Dennis S.C.
- Subjects
- *
EYEGLASSES , *VISUAL acuity , *RURAL geography , *RANDOMIZED controlled trials , *HEALTH outcome assessment , *MEDICAL statistics - Abstract
Objective: To test an educational intervention promoting the purchase of spectacles among Chinese children. Design: Randomized, controlled trial. Participants: Children in years 1 and 2 of all 20 junior and senior high schools (ages 12–17 years) in 3 rural townships in Guangdong, China. Methods: Children underwent visual acuity (VA) testing, and parents of participants with presenting VA worse than 6/12 in either eye improving by more than 2 lines with cycloplegic refraction were recommended to purchase glasses. Children at 10 randomly selected schools received a lecture, video, and classroom demonstration promoting spectacle purchase. Main Outcome Measures: Self-reported purchase of spectacles (primary outcome) and observed wear or possession of newly purchased glasses (secondary outcome) at follow-up examinations (mean, 219±87 days after the baseline visit). Results: Among 15 404 eligible children, examinations were completed for 6379 (74.6%) at intervention schools and 5044 (73.6%) at control schools. Spectacles were recommended for 2236 (35.1%) children at intervention schools and for 2212 (43.9%) at control schools. Of these, 417 (25.7%) intervention schools children and 537 (34.0%, P = 0.45) control schools children reported buying glasses. Predictors of purchase in regression models included female gender (P = 0.02), worse uncorrected VA (P<0.001), and higher absolute value of refractive error (P = 0.001). Neither the rate of self-reported purchase of glasses or observed wear or possession of newly purchased glasses differed between control schools and intervention schools in mixed-effect logistic regression models. Among children not purchasing glasses, 21.7% had better-eye VA of worse than 6/18. Conclusions: An intervention based on extensive pilot testing and focus groups in the area failed to promote spectacle purchase or wear. The high burden of remaining uncorrected poor vision underscores the need to develop better interventions. Financial Disclosure(s): The author(s) have no proprietary or commercial interest in any materials discussed in this article. [Copyright &y& Elsevier]
- Published
- 2011
- Full Text
- View/download PDF
40. The Child Self-Refraction Study: Results from Urban Chinese Children in Guangzhou
- Author
-
He, Mingguang, Congdon, Nathan, MacKenzie, Graeme, Zeng, Yangfa, Silver, Joshua D., and Ellwein, Leon
- Subjects
- *
REFRACTIVE errors , *REFRACTION (Optics) , *EYEGLASSES , *VISUAL acuity , *CROSS-sectional method , *JUVENILE diseases - Abstract
Objective: To compare visual and refractive outcomes between self-refracting spectacles (Adaptive Eyecare, Ltd, Oxford, UK), noncycloplegic autorefraction, and cycloplegic subjective refraction. Design: Cross-sectional study. Participants: Chinese school-children aged 12 to 17 years. Methods: Children with uncorrected visual acuity ≤6/12 in either eye underwent measurement of the logarithm of the minimum angle of resolution visual acuity, habitual correction, self-refraction without cycloplegia, autorefraction with and without cycloplegia, and subjective refraction with cycloplegia. Main Outcome Measures: Proportion of children achieving corrected visual acuity ≥6/7.5 with each modality; difference in spherical equivalent refractive error between each of the modalities and cycloplegic subjective refractive error. Results: Among 556 eligible children of consenting parents, 554 (99.6%) completed self-refraction (mean age, 13.8 years; 59.7% girls; 54.0% currently wearing glasses). The proportion of children with visual acuity ≥6/7.5 in the better eye with habitual correction, self-refraction, noncycloplegic autorefraction, and cycloplegic subjective refraction were 34.8%, 92.4%, 99.5% and 99.8%, respectively (self-refraction versus cycloplegic subjective refraction, P<0.001). The mean difference between cycloplegic subjective refraction and noncycloplegic autorefraction (which was more myopic) was significant (–0.328 diopter [D]; Wilcoxon signed-rank test P<0.001), whereas cycloplegic subjective refraction and self-refraction did not differ significantly (–0.009 D; Wilcoxon signed-rank test P = 0.33). Spherical equivalent differed by ≥1.0 D in either direction from cycloplegic subjective refraction more frequently among right eyes for self-refraction (11.2%) than noncycloplegic autorefraction (6.0%; P = 0.002). Self-refraction power that differed by ≥1.0 D from cycloplegic subjective refractive error (11.2%) was significantly associated with presenting without spectacles (P = 0.011) and with greater absolute power of both spherical (P = 0.025) and cylindrical (P = 0.022) refractive error. Conclusions: Self-refraction seems to be less prone to accommodative inaccuracy than noncycloplegic autorefraction, another modality appropriate for use in areas where access to eye care providers is limited. Visual results seem to be comparable. Greater cylindrical power is associated with less accurate results; the adjustable glasses used in this study cannot correct astigmatism. Further studies of the practical applications of this modality are warranted. Financial Disclosure(s): Proprietary or commercial disclosure may be found after the references. [Copyright &y& Elsevier]
- Published
- 2011
- Full Text
- View/download PDF
41. Reversal in Gender Valuations of Cataract Surgery After the Implementation of Free Screening and Low-Priced High-Quality Surgery in a Rural Population of Southern China.
- Author
-
Baruwa, Elaine, Tzu, Jonathan, Congdon, Nathan, He, Mingguang, and Frick, Kevin D.
- Subjects
CATARACT surgery ,WILLINGNESS to pay ,VISUAL acuity ,VISUAL perception ,VISION testing ,MEDICAL screening - Abstract
Purpose: To assess the impact of community outreach and the availability of low-cost surgeries [500 Renminbi (RMB) or 65 United States dollars (US$) per surgery] on the willingness to pay for cataract surgery among male and female rural-dwelling Chinese. Methods: Cross-sectional willingness-to-pay surveys were conducted at the initiation of a cataract outreach programme in June 2001 and then again in July 2006. Respondents underwent visual acuity testing and provided socio-demographic data. Results: In 2001 and 2006, 325 and 303 subjects, respectively, were interviewed. On average the 2006 sample subjects were of similar age, more likely to be female (p < 0.01), illiterate (p < 0.01), and less likely to come from a household with annual income of less than US$789 (62% vs. 87%, p < 0.01). Familiarity with cataract surgery increased from 21.2% to 44.4% over the 5 years for male subjects (p < 0.01) and 15.8%-44.4% among females (p < 0.01). The proportion of respondents willing to pay at least 500 RMB for surgery increased from 67% to 88% (p < 0.01) among male subjects and from 50% to 91% (p < 0.01) among females. Conclusions: Five years of access to free cataract testing and low-cost surgery programmes appears to have improved the familiarity with cataract surgery and increased the willingness to pay at least 500 RMB (US$65) for it in this rural population. Elderly women are now as likely as men to be willing to pay at least 500 RMB, reversing gender differences present 5 years ago. [ABSTRACT FROM AUTHOR]
- Published
- 2008
- Full Text
- View/download PDF
42. Rapid, objective detection of cataract-induced blur using a bull's eye photodetector
- Author
-
Nusz, Kevin J., Congdon, Nathan G., Ho, Tang, Gramatikov, Boris I., Friedman, David S., Guyton, David L., and Hunter, David G.
- Subjects
- *
CRYSTALLINE lens diseases , *CATARACT , *VISUAL acuity , *HEALTH outcome assessment - Abstract
Purpose: To determine whether optical aberrations caused by cataract can be detected and quantified objectively using a newly described focus detection system (FDS). Setting: The Wilmer Opthalmological Institute, The Johns Hopkins University School of Medicine, Baltimore, Maryland, USA. Methods: The FDS uses a bull''s eye photodetector to measure the double-pass blur produced from a point source of light. To determine the range and level of focus, signals are measured with a series of trial lenses in the light path selected to span the point of best focus to generate focus curves. The best corrected visual acuity (BCVA), refractive error, lens photograph grades, and FDS signals were obtained in 18 patients scheduled to have cataract surgery. The tests were repeated 6 weeks after surgery. Results: The mean FDS outcome measures improved after cataract surgery, with increased peak height (P=.001) and decreased peak width (P=.001). Improvement in signal strength (integral of signal within ±1.5 diopters of the point of best focus) strongly correlated with improvement in peak height (R2=.88, P<.0001) and photographic cataract grade (R2=.72, P<.0001). The mean BCVA improved from 20/50 to 20/26 (P<.0001). The improvement in BCVA correlated more closely with FDS signal strength (R2=.44, P=.001) than with cataract grade (R2=.25, P=.06). Conclusions: Improvement in FDS outcome measures correlated with cataract severity and improvement in visual acuity. This objective approach may be useful in long-term studies of cataract progression. [Copyright &y& Elsevier]
- Published
- 2005
- Full Text
- View/download PDF
43. The impact of uncorrected myopia on individuals and society.
- Author
-
Congdon, Nathan, Burnett, Anthea, and Frick, Kevin
- Subjects
- *
EYE diseases , *ACADEMIC achievement , *EYEGLASSES , *AGE distribution , *CHILD development , *MEDICAL care costs , *MYOPIA , *QUALITY of life , *VISUAL acuity , *CHILDREN , *DISEASE risk factors ,TREATMENT of vision disorders - Published
- 2019
44. Fluid-jet technique to polish the posterior capsule for phacoemulsification surgeries: efficacy and safety evaluation.
- Author
-
Liu, Zhenzhen, Cao, Qianzhong, Qu, Bo, Wang, Wei, Ruan, Xiaoting, Zheng, Danying, Jin, Guangming, Tan, Xuhua, Jin, Ling MS, He, Mingguang, Congdon, Nathan, Lin, Haotian, Luo, Lixia, and Liu, Yizhi
- Subjects
- *
PHACOEMULSIFICATION , *POSTERIOR capsulotomy , *INTRAOCULAR lenses , *VISUAL acuity , *SURGERY - Abstract
Purpose: To compare the efficacy and safety of a fluid-jet technique with capsular polish in reducing residual lens fibers (RLFs) in phacoemulsification surgery. Setting: Single center. Design: Prospective nonrandomized comparative study. Methods: Patients receiving phacoemulsification were included. Consecutive eligible patients alternately underwent either removal of RLFs on the posterior capsule using capsular polish after irrigation and aspiration, and before intraocular lens (IOL) implantation, or RLF removal using a fluid-jet technique after IOL implantation. Posterior capsular images were used to quantify RLFs. Visual parameters were evaluated at 1 day, 1 week, and 1 year postoperatively. The proportion of capsule occupied by posterior capsule opacification (PCO) (area %) and incidence of protocol-driven laser posterior capsulotomy were recorded at 1 year in masked fashion. Results: Seven hundred forty eyes were allocated to polishing (n = 370) or fluid-jet technique (n = 370). Polishing required 70.4 +/- 17.5 seconds and fluid-jet 32.2 +/- 9.9 seconds (P <= 0.001). Compared with the polishing group, capsular area occupied by RLFs in the fluid-jet group was significantly smaller (3.5% vs 0.5%, P =.031) at the end of surgery. One day postoperatively, the fluid-jet group had more desirable corrected distance visual acuity, objective scattering index, and Strehl ratio (all P <.05). PCO area percentage did not differ between groups (6.5% vs 4.5%, P =.252) 1 year postoperatively, but incidence of posterior capsulotomy was lower in the fluid-jet group (3.2% vs 0.8%, P =.019). /> Conclusions: Fluid-jet removed RLFs effectively and had lower incidence of postoperative capsulotomy than capsular polishing. [ABSTRACT FROM AUTHOR]
- Published
- 2020
- Full Text
- View/download PDF
45. A Randomized Noninferiority Trial of Wearing Adjustable Glasses versus Standard and Ready-made Spectacles among Chinese Schoolchildren: Wearability and Evaluation of Adjustable Refraction III.
- Author
-
Wang, Congyao Y., Zhang, Guoshan, Tang, Bobby, Jin, Ling, Huang, Wenyong, Wang, Xiuqin, Chen, Tingting, Zhu, Wenhui, Xiao, Baixiang, Wang, Jun, Zhou, Zhongqiang, Tang, Zhizheng, Liang, Yan, Crescioni, Mabel, Wilson, David, McAneney, Helen, Silver, Joshua D., Moore, Bruce, and Congdon, Nathan
- Subjects
- *
SCHOOL children , *TEACHER evaluation , *SCHOOL principals , *VISUAL acuity , *GLASS - Abstract
To compare wear of standard, adjustable, and ready-made glasses among children. Randomized, controlled, open-label, noninferiority trial. Students aged 11 to 16 years with presenting visual acuity (VA) ≤6/12 in both eyes, correctable to ≥6/7.5, subjective spherical equivalent refractive error (SER) ≤–1.0 diopters (D), astigmatism and anisometropia both <2.00 D, and no other ocular abnormalities. Participants were randomly allocated (1:1:1) to standard glasses, ready-made glasses, or adjustable glasses based on self-refraction. We recorded glasses wear on twice-weekly covert evaluation by head teachers (primary outcome), self-reported and investigator-observed wear, best-corrected visual acuity (BCVA) (not prespecified), children's satisfaction, and value attributed to glasses. Proportion of glasses wear on twice-weekly covert evaluation by head teachers over 2 months. Among 379 eligible participants, 127 were allocated to standard glasses (mean age, 13.7 years; standard deviation [SD], 1.0 years; 54.3% were male), 125 to ready-made (mean age, 13.6; SD, 0.83; 45.6%), and 127 to adjustable (mean age, 13.4 years; SD, 0.85; 54.3%). Mean wear proportion of adjustable glasses was significantly lower than for standard glasses (45% vs. 58%; P = 0.01), although the adjusted difference (90% confidence interval [CI], –19.0% to –3.0%) did not meet the prespecified inferiority threshold of 20%. Self-reported (90.2% vs. 84.8%, P = 0.64) and investigator-observed (44.1% vs. 33.9%, P = 0.89) wear did not differ between standard and adjustable glasses, nor did satisfaction with (P = 0.97) or value attributed to study glasses (P = 0.55) or increase in quality of life (5.53 [SD, 4.47] vs. 5.68 [SD, 4.34] on a 100-point scale, P > 0.30). Best-corrected visual acuity with adjustable glasses was better (P < 0.001) than with standard glasses. Change in power of study lenses at the end of the study (adjustable: 0.65 D, 95% CI, 0.52–0.79; standard, 0.01 D; 95% CI, –0.006 to 0.03, P < 0.001) was greater for adjustable glasses, although interobserver variation in power measurements may explain this. Lens scratches and frame damage were more common with adjustable glasses, whereas lens breakage was less common than for standard glasses. Proportion of wear was lower with adjustable glasses, although VA was better and measures of satisfaction and quality of life were not inferior to standard glasses. [ABSTRACT FROM AUTHOR]
- Published
- 2020
- Full Text
- View/download PDF
46. Age-related Prevalence and Met Need for Correctable and Uncorrectable Near Vision Impairment in a Multi-country Study.
- Author
-
He, Mingguang, Abdou, Amza, Ellwein, Leon B., Naidoo, Kovin S., Sapkota, Yuddha D., Thulasiraj, R.D., Varma, Rohit, Zhao, Jialiang, Kocur, Ivo, and Congdon, Nathan G.
- Subjects
- *
VISION disorders , *TREATMENT of eye refractive errors , *EYE examination , *DISEASE prevalence , *VISUAL acuity , *EYEGLASSES - Abstract
Purpose: To estimate the prevalence, potential determinants, and proportion of met need for near vision impairment (NVI) correctable with refraction approximately 2 years after initial examination of a multi-country cohort. Design: Population-based, prospective cohort study. Participants: People aged ≥35 years examined at baseline in semi-rural (Shunyi) and urban (Guangzhou) sites in China; rural sites in Nepal (Kaski), India (Madurai), and Niger (Dosso); a semi-urban site (Durban) in South Africa; and an urban site (Los Angeles) in the United States. Methods: Near visual acuity (NVA) with and without current near correction was measured at 40 cm using a logarithm of the minimum angle of resolution near vision tumbling E chart. Participants with uncorrected binocular NVA ≤20/40 were tested with plus sphere lenses to obtain best-corrected binocular NVA. Main Outcome Measures: Prevalence of total NVI (defined as uncorrected NVA ≤20/40) and NVI correctable and uncorrectable to >20/40, and current spectacle wearing among those with bilateral NVA ≤20/63 improving to >20/40 with near correction (met need). Results: Among 13 671 baseline participants, 10 533 (77.2%) attended the follow-up examination. The prevalence of correctable NVI increased with age from 35 to 50–60 years and then decreased at all sites. Multiple logistic regression modeling suggested that correctable NVI was not associated with gender at any site, whereas more educated persons aged >54 years were associated with a higher prevalence of correctable NVI in Nepal and India. Although near vision spectacles were provided free at baseline, wear among those who could benefit was <40% at all but 2 centers (Guangzhou and Los Angeles). Conclusions: Prevalence of correctable NVI is greatest among persons of working age, and rates of correction are low in many settings, suggesting that strategies targeting the workplace may be needed. [Copyright &y& Elsevier]
- Published
- 2014
- Full Text
- View/download PDF
Catalog
Discovery Service for Jio Institute Digital Library
For full access to our library's resources, please sign in.