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Impaired vision is caused by refractive errors such as nearsightedness, aging, infection, nutritional and metabolic disorders, and trauma. Impaired vision is one of the most common disorders in the world, affecting an estimated 150 million people worldwide. The Global Vision 2020 program sponsored by the World Health Organization hopes to eliminate two thirds of all preventable blindness by 2020.

Purpose To estimate the disease burden due to intraocular foreign bodies (IOFBs) and evaluate contributions of various risk factors to IOFB-associated disability-adjusted life-years (DALYs). Methods Global, regional and country-level number, rate and age-standardised rate of DALYs due to IOFBs were acquired from the Global Burden of Disease Study 2017 database. The Human Development Index (HDI) and other region and country-level data were obtained from open databases. Time trends for number, rate and age-standardised rate of DALYs due to IOFBs were calculated. Regression analysis was used to evaluate associations between age-standardised rate of DALYs and potential predictors. Results Global DALYs due to IOFBs rose by 43.7% between 1990 (139 (95% CI 70.8 to 233) thousand) and 2017 (202 (95% CI 105 to 335) thousand). The DALY rate remained stable while the age-standardised rate decreased during this period. Higher disease burden due to IOFBs was associated with higher glaucoma prevalence (β=0.006, 95% CI 0.003 to 0.09, p<0.001), lower refractive error prevalence (β=-0.0005, 95% CI -0.0007 to -0.0002, p<0.001), and lower income (β=-0.020, 95% CI -0.035 to -0.006, p=0.007). Conclusion Predictors of a greater burden of IOFB disability generally point to lower socioeconomic level. The association with glaucoma may reflect a complication of IOFB, increasing risk of vision loss and disability. [ABSTRACT FROM AUTHOR]

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]

Purpose To describe changes in the prevalence of visual impairment and glasses ownership with age and as associated with income and population density for visual impairment among rural and urban migrant Chinese students. Design Meta-analysis of 12 cross-sectional, schoolbased studies conducted between 2012 and 2017. Setting Rural and urban migrant schools in seven Chinese provinces. Participants A total of 83 273 rural and urban migrant Chinese students aged 6–17 years. Results Prevalence of visual impairment (uncorrected visual acuity ≤6/12 in either eye) rose from 19.0% at age 6 to 66.9% at 17, with the overall age-adjusted prevalence higher for girls (35.8%) than for boys (30.1%, p<0.001). The rate of glasses ownership among students who needed them increased from 13.0% at age 6 to 63.9% (p<0.001) at 17 and was significantly higher for girls (37.0%) than boys (34.7%, p<0.001). The unmet need for glasses as a proportion of the student population peaked in junior high school (31.8%). A 1% increase in per capita gross domestic product was associated with a 4.45% rise in uncorrected visual acuity (R2 =0.057, p=0.020). Population density was significantly associated with glasses ownership among children (R² =0.359, p=0.012). A 1% population density increase was associated with an increase in the glasses ownership rate of 6.83%. Conclusion Efforts are needed to improve vision screening coverage in China’s schools, particularly junior high schools, as this is when many rural children leave school and glasses coverage is lowest. [ABSTRACT FROM AUTHOR]

To analyze anatomical factors contributing to angle closure based on anterior segment optical coherence tomography (AS-OCT) imaging. A total of 238 patients with angle closure and 1122 normal controls were consecutively recruited for this study. Participants' eyes were imaged using AS-OCT under the same darkened ambient light conditions. The following parameters were analyzed: central anterior chamber depth (ACD); anterior chamber area (ACA); anterior chamber volume (ACV), anterior chamber width (ACW); corneal diameter (CD); posterior cornea curvature (PCC); anterior cornea curvature (ACC); maximum iris thickness (ITM); iris thickness at 750 um (IT750) and 2000 um (IT2000) from the scleral spur; iris curvature (IC); iris area (IA); lens vault (LV); angle opening distance (AOD); trabecular iris space area at 500 um (TISA500) and 750 um (TISA750) from the scleral spur; angle recess area (ARA). Lasso regression models were used to detect the collinearity of parameters. The multivariable logistic regression was performed to determine the independent association between angle closure and those parameters included in Lasso regression model. Also Factor analysis was performed to extract a few underlying factors (components) from these parameters. Lasso regression showed that ACD, ACV, PCC, IT750, IT2000 and LV were screened in the model. The multivariable logistic regression indicated that ACV, PCC, IT750 and LV were significantly associated with angle closure. Factor analyses revealed that 4 factors, each with its closely associated clusters of variables, produced the best results: ACA, ACV and ACD (Factor 1); LV, tIC and nIC, (Factor 2); ACW, CD and PCC (Factor 3); and tITM, tIT2000, tIT750, nIT2000 and nIT750 (Factor 4). Four separate mechanisms were showed to be involved in the pathogenesis of angle closure, from anterior chamber dimensions, lens, iris and cornea respectively. The parameters ACV, PCC, IT750, and LV are more predominant in determining angle closure. [ABSTRACT FROM AUTHOR]

Physiologic indicators reflect the functional consequences of vitamin A deficiency and may be particularly useful for detecting early perturbations in vitamin A status. In conjunctival impression cytology (CIC), epithelial morphology and the presence or absence of mucin spots and goblet cells allow samples, obtained by applying filter paper to the temporal conjunctiva, to be characterized as normal or typical of vitamin A-deficient keratinizing metaplasia. The validity of CIC has been established with reference to other indicators of vitamin A status, and a prevalence of [greater than or equal to] 20% abnormal results has been suggested as indicative of a public health problem. However, interpretation of specimens requires considerable training, and nonresponsiveness to supplementation is a frequent problem, which limits the utility of CIC as a method for evaluating the impact of intervention programs. Several simplified field protocols for dark adaptation have been developed, including one in which dark adaptation is assessed by the responsiveness of the pupil to light. Night blind subjects have consistently shown abnormal results on this test, and a significant response to placebo-controlled dosing has been demonstrated for children and pregnant women. Scores have correlated significantly with serum retinol and relative dose response. Pupillary dark adaptation testing is acceptable to most children as young as 2 y old. Limitations of this technique include a time course for recovery after dosing as long as 4-6 wk, a testing time of 20 min, and the need for 1-3 d of training. Given its low cost, noninvasive nature, and lack of the need to transport samples, pupillary dark adaptation offers advantages over other techniques for assessing a population's vitamin A status. KEY WORDS: * physiologic indicator * conjunctival impression cytology * dark adaptation * vitamin A * pupil

Age related cataract is the leading cause of blindness in the world today, (1) with an estimated 17 million individuals bilaterally blind. (2) Though surgery may be an effective means [...]

Aims To investigate the prevalence and predictors of pseudomyopia in Chinese children and its association with myopia progression. Methods A prospective, school-based, cohort study of 6- and 13-year-old children was conducted in Anyang, China. Pre-cycloplegic and post-cycloplegic autorefraction were performed at baseline and 1 year later. Pseudomyopia was defined as spherical equivalent refractive (SER) error in the better-seeing eye =-0.50 D before cycloplegia and >-0.50 D after cycloplegia. Among pseudomyopic children, pseudomyopic power was defined as non-cycloplegic SER subtracted from cycloplegic SER. Market survey was collected in all optometry stores in Anyang city to investigate how cycloplegia is used for refracting children. Results A total of 2612 children aged 6 years and 1984 children aged 13 years were included. Of the two cohorts, median cycloplegic SER (IQR) was 1.00 D (0.50, 1.38) and -1.13 D (-2.63, 0.13) respectively, myopia prevalence was 5.2% and 61.0%, pseudomyopia prevalence was 24.1% and 18.9%, and median pseudomyopic power was 1.13 D (0.63, 1.63) and 0.38 D (0.13, 0.88). In both cohorts, greater baseline hyperopia was the strongest predictor of pseudomyopia (p<0.001), whereas time spent on near work was not associated with pseudomyopic power (p>0.05). After 1 year, 15.6% (98/629) of 6-year-olds and 10.7% (40/374) of 13-year-olds with pseudomyopia developed myopia. Compared with myopes, pseudomyopic children with the same precycloplegic SER had slower myopic progression (p<0.001). Among all 127 optometry stores in Anyang, only 4 (3.15%) used cycloplegia for refracting children. Conclusion Pseudomyopia is more prevalent in younger, more hyperopic children. Pseudomyopia is not an independent risk factor for myopic progression in this setting. [ABSTRACT FROM AUTHOR]