Search

Background: The epidemic rise of diabetes carries major negative public health and economic consequences particularly for low and middle-income countries. The highest predicted percentage growth in diabetes is in the sub-Saharan Africa (SSA) region where to date there has been no data on the incidence of diabetic retinopathy from population-based cohort studies and minimal data on incident diabetes. The primary aims of this study were to estimate the cumulative six-year incidence of Diabetes Mellitus (DM) and DR (Diabetic Retinopathy), respectively, among people aged ≥50 years in Kenya. Methods: Random cluster sampling with probability proportionate to size were used to select a representative cross-sectional sample of adults aged ≥50 years in 2007-8 in Nakuru District, Kenya. A six-year follow-up was undertaken in 2013-14. On both occasions a comprehensive ophthalmic examination was performed including LogMAR visual acuity, digital retinal photography and independent grading of images. Data were collected on general health and risk factors. The primary outcomes were the incidence of diabetes mellitus and the incidence of diabetic retinopathy, which were calculated by dividing the number of events identified at 6-year follow-up by the number of people at risk at the beginning of follow-up. Age-adjusted risk ratios of the outcomes (DM and DR respectively) were estimated for each covariate using a Poisson regression model with robust error variance to allow for the clustered design and including inverse-probability weighting. Results: At baseline, 4414 participants aged ≥50 years underwent complete examination. Of the 4104 non-diabetic participants, 2059 were followed-up at six-years (50 ⋅ 2%). The cumulative incidence of DM was estimated at 61 ⋅ 0 per 1000 (95% CI: 50 ⋅ 3-73 ⋅ 7) in people aged ≥50 years. The cumulative incidence of DR in the sample population was estimated at 15 ⋅ 8 per 1000 (95% CI: 9 ⋅ 5-26 ⋅ 3) among those without DM at baseline, and 224 ⋅ 7 per 1000 (116.9-388.2) among participants with known DM at baseline. A multivariable risk factor analysis demonstrated increasing age and higher body mass index to be associated with incident DM. DR incidence was strongly associated with increasing age, and with higher BMI, urban dwelling and higher socioeconomic status. Conclusions: Diabetes Mellitus is a growing public health concern with a major complication of diabetic retinopathy. In a population of 1 ⋅ 6 million, of whom 150,000 are ≥50 years, we estimated that 1650 people aged ≥50 develop DM per year, and 450 develop DR. Strengthening of health systems is necessary to reduce incident diabetes and its complications in this and similar settings. [ABSTRACT FROM AUTHOR]

Objectives: To estimate the prevalence of blindness and visual impairment (VI) in adults aged ≥50 years in the Nakuru district of Kenya and to identify sociodemographic risk factors for these conditions. We also sought to validate the Rapid Assessment of Avoidable Blindness (RAAB) methodology. Participants: There were 5010 subjects enumerated for this study. Of these, 4414 participants underwent examination, for a response rate of 88.1%. Design: Cross-sectional, population-based survey. Methods: Cluster random samplings with probability proportionate to size procedures were used to select a representative cross-sectional sample of adults aged ≥50 years. Each participant was interviewed, had distance visual acuity (VA) measured with reduced logarithm of the minimal angle of resolution tumbling-E chart, underwent autorefraction, and thereby had measurements of presenting, uncorrected, and best-corrected VA. All participants, regardless of vision, underwent detailed ophthalmic examinations including slit-lamp assessment and dilated retinal photographs. Main Outcome Measures: Visual acuity of <6/12. Results: A representative sample of 4414 adults were enumerated (response rate, 88.1%). The prevalence of blindness (VA < 3/60 in better eye) was 1.6% (95% confidence interval [CI], 1.2–2.1%) and of VI, 0.4% (95% CI, 0.3–0.7%); 8.1% (95% CI, 7.2–9.2%); and 5.1% (95% CI, 4.3–6.1%) were severely (<6/60–3/60), moderately (<6/18–6/60), or mildly (<6/12–6/18) visually impaired, respectively. Being male, having less education, having Kalenjin tribal origin, and being ≥80 years old were associated with increased blindness prevalence. Prevalence estimates were comparable to a RAAB performed in the same area 2 years earlier. Conclusions: This survey provides reliable estimates of blindness and VI prevalence in Nakuru. Older age and tribal origin were identified as predictors of these conditions. This survey validates the use of RAAB as a method of estimating blindness and VI prevalence. Financial Disclosure(s): The authors have no proprietary or commercial interest in any of the materials discussed in this article. [Copyright &y& Elsevier]

Purpose: To assess the impact of cataract surgery on vision related quality of life (VRQoL) and generic health related quality of life (HRQoL) in Kenya, Bangladesh and the Philippines. Methods: A multi-center intervention study was conducted. At baseline 651 cases aged ≥50 years with visually impairing cataract (corrected visual acuity (VA) <6/24) and 561 age- gender-matched controls with normal vision (VA>6/18) were interviewed about VRQoL (using the World Health Organization/ Prevention of Blindness and Deafness 20-item Visual Functioning Questionnaire [WHO/PBD VF20]) and generic HRQoL (EuroQol). Cases were offered free/subsidized cataract surgery. Approximately 1 year later participants were re-interviewed. Results: Response rate at follow up was 84% for operated cases and 80% for controls. At baseline, cases had significantly poorer VRQoL scores, were more likely to report problems with the EuroQol 5D five descriptive (EQ−SD) domains (mobility, daily activities, self-care, pain, depression/anxiety) and had significantly poorer self-rated health compared to controls. At follow up VRQoL scores of operated cases improved significantly to approximately equal those of controls. Effect sizes were large (> 0.8) regardless of pre-operative VA. Poor outcome from surgery (VA < 6/60) was associated with smaller VRQoL gains. Among operated cases frequency of reported problems with all the EQ-5D reduced significantly compared to baseline in Kenya and the Philippines, and in mobility, daily activities and self-care in Bangladesh. Self-rated health scores increased significantly in each country. HRQoL of controls remained stable from baseline to follow up. Conclusion: This study among adults undergoing cataract surgery in 3 different low-income settings found evidence of improved VRQoL and generic HRQoL to approximately equal that of controls with normal vision. [ABSTRACT FROM AUTHOR]

Background: Poverty and blindness are believed to be intimately linked, but empirical data supporting this purported relationship are sparse. The objective of this study is to assess whether there is a reduction in poverty after cataract surgery among visually impaired cases. Methodology/Principal Findings: A multi-centre intervention study was conducted in three countries (Kenya, Philippines, Bangladesh). Poverty data (household per capita expenditure - PCE, asset ownership and self-rated wealth) were collected from cases aged ≥50 years who were visually impaired due to cataract (visual acuity<6/24 in the better eye) and age-sex matched controls with normal vision. Cases were offered free/subsidised cataract surgery. Approximately one year later participants were re-interviewed about poverty. 466 cases and 436 controls were examined at both baseline and follow-up (Follow up rate: 78% for cases, 81% for controls), of which 263 cases had undergone cataract surgery ("operated cases"). At baseline, operated cases were poorer compared to controls in terms of PCE (Kenya: $22 versus £35 p = 0.02, Bangladesh: $16 vs $24 p = 0.004, Philippines: $24 vs 32 p = 0.0007), assets and self-rated wealth. By follow-up PCE had increased significantly among operated cases in each of the three settings to the level of controls (Kenya: $30 versus £36 p = 0.49, Bangladesh: $23 vs $23 p = 0.20, Philippines: $45 vs $36 p = 0.68). There were smaller increases in self-rated wealth and no changes in assets. Changes in PCE were apparent in different socio-demographic and ocular groups. The largest PCE increases were apparent among the cases that were poorest at baseline. Conclusions/Significance: This study showed that cataract surgery can contribute to poverty alleviation, particularly among the most vulnerable members of society. This study highlights the need for increased provision of cataract surgery to poor people and shows that a focus on blindness may help to alleviate poverty and achieve the Millennium Development Goals. [ABSTRACT FROM AUTHOR]

Background: Cataract is the leading cause of blindness in the world, and blindness from cataract is particularly common in low-income countries. The aim of this study is to explore the impact of cataract surgery on daily activities and time-use in Kenya, Bangladesh and the Philippines. Methods/Principal Findings: Amulti-centre intervention study was conducted in three countries. Time-use data were collected through interview fromcases aged≥50 years with visually impairing cataract (VA,6/24) and age- and gender-matched controls with normal vision (VA≥6/18). Cases were offered free/subsidized cataract surgery. Approximately one year later participants were re-interviewed about time-use. At baseline across the three countries there were 651 cases and 571 controls. Fifty-five percent of cases accepted surgery. Response rate at follow up was 84% (303 out of 361) for operated cases, and 80% (459 out of 571) for controls. At baseline, cases were less likely to carry out and spent less time on productive activities (paid and non-paid work) and spent more time in ''inactivity'' compared to controls. Approximately one year after cataract surgery, operated cases were more likely to undertake productive activities compared to baseline (Kenya from 55% to 88%; Bangladesh 60% to 95% and Philippines 81% to 94%, p,0.001) and mean time spent on productive activities increased by one-two hours in each setting (p,0.001). Time spent in ''inactivity'' in Kenya and Bangladesh decreased by approximately two hours (p,0.001). Frequency of reported assistance with activities was more than halved in each setting (p,0.001). Conclusions/Significance: The empirical evidence provided by this study of increased time spent on productive activities, reduced time in inactivity and reduced assistance following cataract surgery among older adults in low-income settings has positive implications for well-being and inclusion, and supports arguments of economic benefit at the household level from cataract surgery. [ABSTRACT FROM AUTHOR]

Hannah Kuper and colleagues report a population-based case-control study conducted in three countries that found an association between poverty and visual impairment from cataract. [ABSTRACT FROM AUTHOR]

Purpose: Cataract is the leading cause of blindness in the world, and is particularly common in low-income countries. Cataract is asserted to increase poverty through reduced productivity; however there is a lack of empirical data supporting this claim. The aim of this study was to examine the relationship between visual impairment from cataract with time-use in adults (aged ≥ 50 years) in Kenya, Bangladesh, and The Philippines. Methods: A population-based case-control study was conducted in three countries. Detailed time-use data were collected through interview from 139, 216 and 238 cases with visually impairing cataract and 124, 280 and 163 controls with normal vision in Kenya, Bangladesh and Philippines, respectively during 2005-2006. Results: Cases were substantially less likely than controls to participate in productive activities, including paid work and non-market activities (odds ratio [OR] across three countries is 0.2 95% confidence interval (CI): 0.1-0.3) and in leisure outside of the household (OR 0.7, 95% CI: 0.5, 0.9). Among cases, those with more severe visual impairment spent significantly less time on productive activities and leisure outside of the home, and more time on “no particular activity” (Kenya and Bangladesh) or leisure in the home (The Philippines). Cases were substantially more likely to require assistance in any activity than controls in Kenya (OR 9.8, 95% CI: 3.3, 29.8), Bangladesh (OR 8.6, 95% CI: 5.1-14.4) and the Philippines (OR 2.7, 95% CI: 1.4-5.1). Conclusions: Cataract visual impairment restricts engagement in productive and leisure activities in this population of older adults in three different low income settings. [ABSTRACT FROM AUTHOR]

Background: Presbyopia is the most common reason for requiring spectacles in low-income regions, although the unmet need for presbyopic spectacles in these regions is very high. The aim of this study was to estimate the prevalence of presbyopia, and the functional impairment and spectacle use among persons with presbyopia in a rural Kenyan population. Methods: A cross-sectional study was carried out in the Rift Valley, Kenya. Clusters were selected through probability-proportionate to size sampling, and people aged ≥50 years within the clusters were identified through compact segment sampling. Within the context of this survey, 130 eligible participants were selected for interview and underwent near-vision testing. Functional presbyopia was defined as requiring at least +1.00 dioptre in order to read the N8 optotype at a distance of 40 cm in the participant's usual visual state. Participants were corrected to the nearest 0.25 dioptre in order to see N8. Unmet and met presbyopic need, and presbyopic correction coverage were calculated. Results: Functional presbyopia was found in 111 participants (85.4%). Mean age was lower in those with presbyopia (64.1 years vs. 71.5 years, P = 0.004). Increasing degree of addition required to see N8 was significantly associated with increased difficulty with reading ( P = 0.04), sewing ( P = 0.03), recognizing small objects ( P = 0.02) and harvesting grains ( P = 0.05). Among participants with functional presbyopia, 5.4% wore reading glasses and 25.2% had prior contact with an eye care professional. The unmet presbyopic need was 80.0%, met presbyopic need was 5.4% and presbyopic correction coverage was 6.3%. Cost was cited as the main barrier to spectacle use in 62% of participants with presbyopia. Conclusion: In low-income regions, there is a high prevalence of uncorrected presbyopia, which is associated with near-vision functional impairment. Provision of spectacles for near vision remains a priority in low-income regions. [ABSTRACT FROM AUTHOR]

Aims: To evaluate the World Health Organization Prevention of Blindness and Deafness 20-item Visual Functioning Questionnaire (WHO/PBD VF20), a vision-related quality of life scale, and to describe the relationship between cataract visual impairment and vision- and generic health-related quality of life, in people ⩾50 years of age in Nakuru district, Kenya. Methods: The WHO/PBD VF20 was pilot tested and modified. 196 patients with visual impairment from cataract and 128 population-based controls without visual impairment from cataract were identified through a district-wide survey. Additional cases were identified through case finding. Vision- and health-related quality of life were assessed using the WHO/PBD VF20 scale and EuroQol generic health index (European Quality of Life Questionnaire (EQ-5D)), respectively. WHO/PBD VF20 was evaluated using standard psychometric tests, including factor analysis to determine item grouping for summary scores. Results: The modified WHO/PBD VF20 demonstrated good psychometric properties. Two subscales (general functioning and psychosocial) and one overall eyesight-rating item were appropriate for these data. Increased severity of visual impairment in cases was associated with worsening general functioning, psychosocial and overall eyesight scores (p for trend <0.001). Cases were more likely to report problems with EQ-5D descriptive dimensions than controls (p<0.001), and, among cases, increased severity of visual impairment was associated with worsening self-rated health score. Conclusion: The modified WHO/PBD VF2O is a valid and reliable scale to assess vision-related quality of life associated with cataract visual impairment in this Kenyan population. The association between health-related quality of life and visual impairment reflects the wider implications of cataract for health and well-being, beyond visual acuity alone. [ABSTRACT FROM AUTHOR]

Objectives: To estimate the prevalence of avoidable blindness in ≥50-year-olds in Nakuru district, Kenya, and to evaluate the Rapid Assessment for Avoidable Blindness (RAAB), a new methodology to measure the magnitude and causes of blindness. Design: Cross-sectional population-based survey. Participants: Seventy-six clusters of 50 people 50 years or older were selected by probability proportionate to size sampling of clusters. Households within clusters were selected through compact segment sampling. Three thousand seven hundred eighty-four eligible subjects were selected, of whom 3503 (92.6%) were examined. Methods: Participants underwent a comprehensive ophthalmic examination in their homes by an ophthalmologist, including measurement of visual acuity (VA) with a tumbling-E chart and the diagnosis of the principal cause of visual impairment. Those who had undergone cataract surgery were questioned about the details of the operation and their satisfaction with surgery. Those who were visually impaired from cataract were asked why they had not gone for surgery. Main Outcome Measures: Visual acuity and principal cause of VA<6/18. Results: The prevalence of bilateral blindness (presenting VA < 3/60) was 2.0% (95% confidence interval [CI], 1.5%–2.4%), and prevalence of bilateral visual impairment (VA of <6/18–≥6/60) was 5.8% (95% CI, 4.8%–6.8%) in the sample. Definite avoidable causes of blindness (i.e., cataract, refractive error, trachoma, and corneal scarring) were responsible for 69.6% of bilateral blindness and 74.9% of bilateral visual impairment. Cataract was the major cause of blindness (42.0%) and visual impairment (36.0%). The cataract surgical coverage was high, with 78% of those with bilateral cataract who needed surgery having had surgery at VA<3/60. The quality of surgery was of concern because 22% of the 222 eyes that had undergone cataract surgery had VA<6/60 with best correction. The main barriers to surgery were lack of awareness and cost. The RAAB methodology was easy to use, and each team could visit one cluster per day. Conclusions: The prevalence of blindness in ≥50-year-olds in Nakuru district was low, in part due to the high cataract surgical coverage. The RAAB is easy to use and inexpensive and provides information about the magnitude and causes of avoidable blindness that can be used for planning and monitoring eye care services. [Copyright &y& Elsevier]

Objective To estimate the prevalence and causes of vitamin A deficiency disorders (VADD) in adult male prisoners in Nakuru, Kenya. Methods A total of 1048 male prisoners aged ≥16 years in Nakuru Government of Kenya prison in Nakuru, Kenya were examined by an ophthalmologist for signs of xerophthalmia. Two hundred and forty-one cases with xerophthalmia and 448 controls randomly selected from the remaining prison population were interviewed about risk factors for xerophthalmia and blood samples were taken to measure serum retinol and haemoglobin. Results 23.6% (95% CI = 21.1–26.3%) of examined inmates showed at least one sign of xerophthalmia, mostly night blindness (98.8% of cases). In the case–control study, the age-adjusted analyses showed that xerophthalmia was associated with age, length of imprisonment and previous imprisonment. Men with xerophthalmia were significantly more likely be in poor health characterised by significant illness, recent hospital admission, persistent cough, diarrhoea, fever or chronic illness. After multivariate adjustment, duration of imprisonment remained strongly associated with xerophthalmia (OR comparing >4 years with <6 months = 20.1, 95% CI = 8.3–48.8). Previous imprisonment, fever, diarrhoea, hospital admission and chronic illness were also significant predictors. Serum retinol levels were significantly lower in cases than controls, while there was no difference in haemoglobin levels. Conclusion Vitamin A deficiency was a significant public health problem among these Kenyan male prisoners, indicating that it may be important in vulnerable groups other than young children and pregnant or lactating women. [ABSTRACT FROM AUTHOR]

Objective: To estimate the association between (1) visual impairment (VI) and (2) eye disease and 6-year mortality risk within a cohort of elderly Kenyan people., Design, Setting and Participants: The baseline of the Nakuru Posterior Segment Eye Disease Study was formed from a population-based survey of 4318 participants aged ≥50 years, enrolled in 2007-2008. Ophthalmic and anthropometric examinations were undertaken on all participants at baseline, and a questionnaire was administered, including medical and ophthalmic history. Participants were retraced in 2013-2014 for a second examination. Vital status was recorded for all participants through information from community members. Cumulative incidence of mortality, and its relationship with baseline VI and types of eye disease was estimated. Inverse probability weighting was used to adjust for non-participation., Primary Outcome Measures: Cumulative incidence of mortality in relation to VI level at baseline., Results: Of the baseline sample, 2170 (50%) were re-examined at follow-up and 407 (10%) were known to have died (adjusted risk of 11.9% over 6 years). Compared to those with normal vision (visual acuity (VA) ≥6/12, risk=9.7%), the 6-year mortality risk was higher among people with VI (<6/18 to ≥6/60; risk=28.3%; risk ratio (RR) 1.75, 95% CI 1.28 to 2.40) or severe VI (SVI)/blindness (<6/60; risk=34.9%; RR 1.98, 95% CI 1.04 to 3.80). These associations remained after adjustment for non-communicable disease (NCD) risk factors (mortality: RR 1.56, 95% CI 1.14 to 2.15; SVI/blind: RR 1.46, 95% CI 0.80 to 2.68). Mortality risk was also associated with presence of diabetic retinopathy at baseline (RR 3.18, 95% CI 1.98 to 5.09), cataract (RR 1.26, 95% CI 0.95 to 1.66) and presence of both cataract and VI (RR 1.57, 95% CI 1.24 to 1.98). Mortality risk was higher among people with age-related macular degeneration at baseline (with or without VI), compared with those without (RR 1.42, 95% CI 0.91 to 2.22 and RR 1.34, 95% CI 0.99 to 1.81, respectively)., Conclusions: Visual acuity was related to 6-year mortality risk in this cohort of elderly Kenyan people, potentially because both VI and mortality are related to ageing and risk factors for NCD., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2019. Re-use permitted under CC BY. Published by BMJ.)

Importance: Half of all the cases of blindness worldwide are associated with cataract. Cataract disproportionately affects people living in low- and middle-income countries and persons of African descent., Objective: To estimate the 6-year cumulative incidence of visually impairing cataract in adult participants in the Nakuru Eye Disease Cohort Study in Kenya., Design, Setting, and Participants: This secondary analysis of the Nakuru Eye Disease Cohort Study was conducted from February 2016 to April 2016. This cohort comprised citizens of Nakuru, Kenya, aged 50 years or older who consented to participate in the initial or baseline survey from January 2007 to November 2008, as well as the follow-up conducted from January 2013 to March 2014. All participants at baseline (n = 4364) and follow-up (n = 2159) underwent ophthalmic examination., Main Outcomes and Measures: Six-year cumulative incidence of visually impairing cataract, risk factors of incidence, population estimates, and required cataract surgical rates to manage incident visually impairing cataract., Results: In total, 4364 individuals (with a mean [SD] age of 63.4 [10.5] years and with 2275 women [52.1%]) had complete eye examinations at baseline, and 2159 participants (with a mean [SD] age of 62.5 [9.3] years and with 1140 men [52.8%]) were followed up 6 years later. The 6-year cumulative incidence of visually significant cataract in either eye was 251.9 per 1000 (95% CI, 228.5-276.8), with an increase with age from 128.9 (95% CI, 107.9-153.2) per 1000 for the group aged 50 to 59 years to 624.5 (95% CI, 493.1-739.9) per 1000 for the group aged 80 years or older. This equated to an annual incidence of visually significant cataract of 45.0 per 1000 people aged 50 years or older. Multivariable analysis showed alcohol consumption (risk ratio [RR], 1.4; 95% CI, 1.1-1.8), diabetes (RR, 1.7; 95% CI, 1.3-2.3), educational level, and increasing age (RR, 3.8; 95% CI, 2.6-5.5 for those aged ≥80 years) were associated with incident visually impairing cataract. Extrapolations to all people aged 50 years or older in Kenya indicated that 148 280 (95% CI, 134 510-162 950) individuals might develop new visually impairing cataract in either eye (visual acuity <6/18 in the worse-seeing eye) and that 9540 (95% CI, 6610-13 750) might become cataract blind in both eyes (visual acuity <3/60 in better-seeing eye)., Conclusions and Relevance: Adults in Kenya appeared to have a high incidence of visually impairing cataract, making cataract a priority for blindness prevention programs in the region; surgical interventions and awareness of these services are also required.

Background/objectives: To develop age- and sex-specific centile reference curves for fat-free mass (FFM) and fat mass (FM) adjusted for height in an adult Kenyan population and to investigate the association between FM, FFM and blood pressure (BP)., Subjects/methods: Measures of body composition from bioimpedance analyses and BP were collected in 1995 participants aged ≥50 years in Nakuru County, Kenya. Reference curves were produced using the LMS method. Multivariable linear regression models were used to test the cross-sectional association between body composition indexes and BP., Results: The age- and sex-specific reference curves for body composition (FMI and FFMI) confirmed that FFMI is lower in both men and women with increasing age. FMI declines with age in women while among men the decline starts after 70 years. FFM was higher in men (47.4 ± 7.2 kg) than in women (38.8 ± 5.5 kg), while FM was lower in men (17.3 ± 8.1 kg) than in women (24.4 ± 10.2 kg). FMI, FFMI and BMI were all positively associated with systolic and diastolic BP, and after adjusting for body weight, FFMI remained positively associated with systolic BP and the FMI remained positively associated with diastolic BP. There was no evidence to suggest that FMI and FFMI were superior to measurement of BMI alone., Conclusions: These body composition reference curves provide normative data on body composition for older adults in Kenya. Further research should consider the prospective associations with health, including frailty-related outcomes.

Purpose: Glaucoma is a leading cause of blindness in people of African descent. Minimal data is available from African population-based cohort studies. The primary aims of this study were to describe the normative distribution of glaucoma features to enable glaucoma classification and to assess risk factors for those with glaucoma at follow-up among people aged 50 years and above in Kenya., Materials and Methods: Random cluster sampling with probability proportionate to size was used to select a representative cross-sectional sample of adults aged 50 years and above in 2007 to 2008 in Nakuru District, Kenya. A 6-year follow-up was undertaken in 2013 to 2014. Comprehensive ophthalmic examination included visual acuity, digital retinal photography, visual fields, intraocular pressure, optical coherence tomography, and independent grading of optic nerve images. We report glaucoma features, prevalence and predictors for glaucoma based on the International Society for Geographical & Epidemiological Ophthalmology (ISGEO) criteria. Measures were estimated using a Poisson regression model and including inverse-probability weighting for loss to follow-up., Results: At baseline, 4414 participants aged 50 years and above underwent examination. Anterior chamber optical coherence tomography findings: mean anterior chamber angle of 36.6 degrees, mean central corneal thickness of 508.1 μm and a mean anterior chamber depth of 2.67 mm. A total of 2171 participants were examined at follow-up. The vertical cup to disc ratio distribution was 0.7 and 0.8 at the 97.5th and 99.5th percentiles, respectively. A total of 88 (4.3%, 95% confidence interval, 3.5%-5.9%) of participants at follow-up had glaucoma consistent with ISGEO criteria. A relative afferent pupillary defect and raised intraocular pressure were associated with the diagnosis., Conclusions: Glaucoma is a public health challenge in low-resource settings. Research into testing and treatment modalities in Africa is needed.

Objective: Digital retinal imaging is an established method of screening for diabetic retinopathy (DR). It has been established that currently about 1% of the world's blind or visually impaired is due to DR. However, the increasing prevalence of diabetes mellitus and DR is creating an increased workload on those with expertise in grading retinal images. Safe and reliable automated analysis of retinal images may support screening services worldwide. This study aimed to compare the Iowa Detection Program (IDP) ability to detect diabetic eye diseases (DED) to human grading carried out at Moorfields Reading Centre on the population of Nakuru Study from Kenya., Participants: Retinal images were taken from participants of the Nakuru Eye Disease Study in Kenya in 2007/08 (n = 4,381 participants [NW6 Topcon Digital Retinal Camera])., Methods: First, human grading was performed for the presence or absence of DR, and for those with DR this was sub-divided in to referable or non-referable DR. The automated IDP software was deployed to identify those with DR and also to categorize the severity of DR., Main Outcome Measures: The primary outcomes were sensitivity, specificity, and positive and negative predictive value of IDP versus the human grader as reference standard., Results: Altogether 3,460 participants were included. 113 had DED, giving a prevalence of 3.3% (95% CI, 2.7-3.9%). Sensitivity of the IDP to detect DED as by the human grading was 91.0% (95% CI, 88.0-93.4%). The IDP ability to detect DED gave an AUC of 0.878 (95% CI 0.850-0.905). It showed a negative predictive value of 98%. The IDP missed no vision threatening retinopathy in any patients and none of the false negative cases met criteria for treatment., Conclusions: In this epidemiological sample, the IDP's grading was comparable to that of human graders'. It therefore might be feasible to consider inclusion into usual epidemiological grading.

Purpose: To estimate the prevalence of and factors associated with diabetic retinopathy (DR) among people aged ≥ 50 years in Nakuru, Kenya., Methods: Probability-proportional-to-size sampling was used to select 100 clusters of 50 people aged ≥ 50 years during 2007-2008. Households within clusters were selected through compact segment sampling. Participants underwent dilated slit lamp biomicroscopy (SLB) by an ophthalmologist and digital retinal photography. Images were graded for DR at the Moorfields Eye Hospital Reading Centre, UK. Diagnosis of DR was based on retinal images where available, otherwise on SLB. Anthropometric measures, including random glucose, and lifestyle factors were measured., Results: We examined 4414 adults (response rate 88.1%), of whom 287 had diabetes. A total of 277 of these were screened for DR by SLB, and 195 also underwent retinal photography. The prevalence of any DR diagnosed by retinal images among diabetics was 35.9% (95% confidence interval, CI, 29.7-42.6%). The most common grade of DR was mild/moderate non-proliferative DR (NPDR; 22.1%, 95% CI 16.1-29.4%), while severe NPDR and proliferative DR were less frequent (13.9%, 95% CI 10.0-18.8%). SLB significantly underdiagnosed DR compared to retinal photography, particularly for milder grades. Of 87 individuals with DR, 23 had visual impairment (visual acuity <6/12). DR was associated with younger age, male sex, duration and control of diabetes, and treatment compliance. Coverage of photocoagulation in those needing immediate laser was low (25%)., Conclusion: DR remains a threat to sight in people with diabetes in this elderly Kenyan population. Screening diabetics may enable those requiring treatment to be identified in time to preserve their sight.

Background: No longitudinal data from population-based studies of eye disease in sub-Saharan-Africa are available. A population-based survey was undertaken in 2007/08 to estimate the prevalence and determinants of blindness and low vision in Nakuru district, Kenya. This survey formed the baseline to a six-year prospective cohort study to estimate the incidence and progression of eye disease in this population., Methods/design: A nationally representative sample of persons aged 50 years and above were selected between January 2007 and November 2008 through probability proportionate to size sampling of clusters, with sampling of individuals within clusters through compact segment sampling. Selected participants underwent detailed ophthalmic examinations which included: visual acuity, autorefraction, visual fields, slit lamp assessment of the anterior and posterior segments, lens grading and fundus photography. In addition, anthropometric measures were taken and risk factors were assessed through structured interviews. Six years later (2013/2014) all subjects were invited for follow-up assessment, repeating the baseline examination methodology., Discussion: The methodology will provide estimates of the progression of eye diseases and incidence of blindness, visual impairment, and eye diseases in an adult Kenyan population.

A cross-sectional study was undertaken in Nakuru, Kenya to assess the prevalence of refractive error and the spectacle coverage in a population aged ≥50 years. Of the 5,010 subjects who were eligible, 4,414 underwent examination (response rate 88.1 %). LogMAR visual acuity was assessed in all participants and refractive error was measured in both eyes using a Topcon auto refractor RM8800. Detailed interviews were undertaken and ownership of spectacles was assessed. Refractive error was responsible for 51.7 % of overall visual impairment (VI), 85.3 % (n = 191) of subjects with mild VI, 42.7 % (n = 152) of subjects with moderate VI, 16.7 % (n = 3) of subjects with severe VI and no cases of blindness. Myopia was more common than hyperopia affecting 59.5 % of those with refractive error compared to 27.4 % for hyperopia. High myopia (<-5.0 DS) was also more common than extreme hyperopia (>+5.0 DS). Of those who needed distance spectacles (spectacle coverage), 25.5 % owned spectacles. In conclusion, the oldest, most poor and least educated are most likely to have no spectacles and they should be specifically targeted when refractive services are put in place.

Purpose: Cataract is the leading cause of blindness worldwide, and is particularly common in low- and middle-income countries. Our study aims to identify the predictors for and barriers to acceptance of cataract surgery in Kenya, Bangladesh and the Philippines., Methods: Cases were individuals aged ≥50 years and with best corrected VA of <6/24 in the better eye due to cataract who were identified through population-based surveys and community-based case detection. Cases were asked why they had not attended for surgery. They were offered free cataract surgery and followed-up at one year. Non-acceptors were interviewed to identify barriers to accepting surgery., Results: Of all participants, 58.6% attended for cataract surgery in Kenya, 53.9% Bangladesh and 47.1% the Philippines. Younger age was a predictor for attendance for surgery in all three countries. In Bangladesh and Kenya, male gender and psychosocial score were predictors. At baseline "cost" and "unaware of cataract" were most frequently reported barriers to uptake of surgery in the three settings. At follow-up, "surgical services inaccessible" was one of the two most frequently reported barriers in Kenya and the Philippines while "fear" was most frequently reported in Bangladesh and the Philippines. There were no consistent predictors of the most frequently reported barriers across the different settings., Conclusions: Future services need to focus on increasing uptake among older people and women. Cost is often reported as a barrier but this may conceal more complicated underlying barriers which need to be explored through in-depth qualitative research., Implications for Rehabilitation: Cataract is the leading cause of blindness worldwide, and is particularly common in low- and middle-income countries. Evidence suggests that even when surgical services are available, there can be a lack of demand and low utilization resulting from barriers to uptake. Older cataract patients, females and especially older females are least likely to attend for surgery. Future cataract surgical programmes should put special emphasis on targeting and increasing uptake in these groups.

Objectives: We examined the extent to which the association between socioeconomic position (SEP) and later life prevalence of hypertension, diabetes and visual impairment in Nakuru, Kenya is mediated by health-related behaviour., Methods: We used data from a community survey of 4,314 participants sampled from urban and rural areas in Nakuru, Kenya. Structural equation modelling was employed to estimate the direct and indirect--via health-related behaviour--effects of SEP on the three health outcomes., Results: The accumulation of material resources was positively associated with hypertension and diabetes, whereas both education and material resources had a negative association with the prevalence of visual impairment. However, the observed health inequalities were not due to variation between SEP groups in health-related behaviour., Conclusions: The pattern of associations between education, material resources and the three health outcomes varied, suggesting that in Kenya, unlike the observed pattern of inequalities in high income countries, different dimensions of SEP provide different aspects of protection as well as risk. Smoking and alcohol use did not appear to mediate the observed associations, in contrast with countries past the epidemiologic transition.

Background: Diseases of the posterior segment of the eye, including age-related macular degeneration (AMD), have recently been recognised as the leading or second leading cause of blindness in several African countries. However, prevalence of AMD alone has not been assessed. We hypothesized that AMD is an important cause of visual impairment among elderly people in Nakuru, Kenya, and therefore sought to assess the prevalence and predictors of AMD in a diverse adult Kenyan population., Methods and Findings: In a population-based cross-sectional survey in the Nakuru District of Kenya, 100 clusters of 50 people 50 y of age or older were selected by probability-proportional-to-size sampling between 26 January 2007 and 11 November 2008. Households within clusters were selected through compact segment sampling. All participants underwent a standardised interview and comprehensive eye examination, including dilated slit lamp examination by an ophthalmologist and digital retinal photography. Images were graded for the presence and severity of AMD lesions following a modified version of the International Classification and Grading System for Age-Related Maculopathy. Comparison was made between slit lamp biomicroscopy (SLB) and photographic grading. Of 4,381 participants, fundus photographs were gradable for 3,304 persons (75.4%), and SLB was completed for 4,312 (98%). Early and late AMD prevalence were 11.2% and 1.2%, respectively, among participants graded on images. Prevalence of AMD by SLB was 6.7% and 0.7% for early and late AMD, respectively. SLB underdiagnosed AMD relative to photographic grading by a factor of 1.7. After controlling for age, women had a higher prevalence of early AMD than men (odds ratio 1.5; 95% CI, 1.2-1.9). Overall prevalence rose significantly with each decade of age. We estimate that, in Kenya, 283,900 to 362,800 people 50 y and older have early AMD and 25,200 to 50,500 have late AMD, based on population estimates in 2007., Conclusions: AMD is an important cause of visual impairment and blindness in Kenya. Greater availability of low vision services and ophthalmologist training in diagnosis and treatment of AMD would be appropriate next steps. Please see later in the article for the Editors' Summary.

Purpose: Type 2 idiopathic macular telangiectasia (MacTel) is a progressive retinal disease associated with a slow deterioration of visual acuity, starting in the fifth to seventh decades of life. The etiology and pathogenesis of the disease are little known, and no effective therapy is available. We aimed to estimate the prevalence and describe the phenotype of type 2 MacTel in two African populations., Methods: From two population-based cross-sectional surveys conducted nationally in Nigeria and in the Nakuru district of Kenya, patients with fundus features of type 2 MacTel were selected. Diagnosis was based on color fundus images, grading performed according to the MacTel Study protocol and staged using the Gass and Blodi system. Disease phenotype and clinical characteristics of affected participants were assessed., Results: Of 8599 total participants, five showed a phenotype compatible with type 2 MacTel. Prevalence was estimated as 0.06% (95% confidence interval [CI] 0.02-0.21%) in Kenya, 0.06% (95% CI 0.01-0.17%) in Nigeria, and overall at 0.06% (95% CI 0.02-0.14%). Mean age was 62 years (SD 5 years), four of five affected participants were female, and none had a history of diabetes. Median corrected visual acuity was 6/12 in the better eye and 6/69 in the worse eye., Conclusions: The estimated prevalence and phenotype of type 2 MacTel in the African populations examined were similar to those in predominantly white populations. All data published so far are based on the analysis of color fundus images only and are thus likely to underestimate the true prevalence of this disease.

Background: Cardiovascular disease (CVD) is the leading cause of death among older people in Africa. This study aimed to investigate the relationship of urbanization and ethnicity with CVD risk markers in Kenya., Methods: A cross-sectional population-based survey was carried out in Nakuru Kenya in 2007-2008. 100 clusters of 50 people aged ≥ 50 years were selected by probability proportionate to size sampling. Households within clusters were selected through compact segment sampling. Participants were interviewed by nurses to collect socio-demographic and lifestyle information. Nurses measured blood pressure, height, weight and waist and hip circumference. A random finger-prick blood sample was taken to measure glucose and cholesterol levels.Hypertension was defined as systolic blood pressure (SBP) ≥ 140 mm Hg, or diastolic blood pressure (DBP) ≥ 90 mm Hg or current use of antihypertensive medication; Diabetes as reported current medication or diet control for diabetes or random blood glucose level ≥ 11.1 mmol/L; High cholesterol as random blood cholesterol level ≥ 5.2 mmol/L; and Obesity as Body Mass Index (BMI)≥ 30 kg/m2., Results: 5010 eligible subjects were selected, of whom 4396 (88%) were examined. There was a high prevalence of hypertension (50.1%, 47.5-52.6%), obesity (13.0%, 11.7-14.5%), diabetes (6.6%, 5.6-7.7%) and high cholesterol (21.1%, 18.6-23.9). Hypertension, diabetes and obesity were more common in urban compared to rural groups and the elevated prevalence generally persisted after adjustment for socio-demographic, lifestyle, obesity and cardiovascular risk markers. There was also a higher prevalence of hypertension, obesity, diabetes and high cholesterol among Kikuyus compared to Kalenjins, even after multivariate adjustment. CVD risk markers were clustered both across the district and within individuals. Few people received treatment for hypertension (15%), while the majority of cases with diabetes received treatment (68%)., Conclusions: CVD risk markers are common in Kenya, particularly in urban areas. Exploring differences in CVD risk markers between ethnic groups may help to elucidate the epidemiology of these conditions.