Praveen Vashist

Current status of cataract blindness and Vision 2020: the right to sight initiative in India.

Background: India is a signatory to the World Health Organization resolution on Vision 2020: The right to sight. Efforts of all stakeholders have resulted in increased number of cataract surgeries performed in India, but the impact of these efforts on the elimination of avoidable blindness is unknown. Aims: Projection of performance of cataract surgery over the next 15 years to determine whether India is likely to eliminate cataract blindness by 2020. Materials and Methods: Data from three national level blindness surveys in India over three decades, and projected age-specific population till 2020 from US Census Bureau were used to develop a model to predict the magnitude of cataract blindness and impact of Vision 2020: the right to sight initiatives. Results: Using age-specific data for those aged 50+ years it was observed that prevalence of blindness at different age cohorts (above 50 years) reduced over three decades with a peak in 1989. Projections show that among those aged 50+ years, the quantum of cataract surgery would double (3.38 million in 2001 to 7.63 million in 2020) and cataract surgical rate would increase from 24025/million 50+ in 2001 to 27817/million 50+ in 2020. Though the prevalence of cataract blindness would decrease, the absolute number of cataract blind would increase from 7.75 million in 2001 to 8.25 million in 2020 due to a substantial increase in the population above 50 years in India over this period. Conclusions: Considering existing prevalence and projected incidence of cataract blindness over the period 2001-2020, visual outcomes after cataract surgery and sight restoration rate, elimination of cataract blindness may not be achieved by 2020 in India.

Prevalence of Early and Late Age-Related Macular Degeneration in India: The INDEYE Study

PURPOSE To estimate the prevalence of early and late age-related macular degeneration (AMD) in India. METHODS Of 7518 people aged 60 years and older identified from randomly sampled villages in North and South India, 5853 (78%) attended an eye examination including fundus photography. Fundus images were graded according to the Wisconsin Age-Related Maculopathy Grading System. RESULTS Fundus images were ungradable in 1587 people, mainly because of cataract. People 80 years of age and older were less likely to attend the eye examination and more likely to have ungradable images. For ages 60 to 79 years, the percent prevalence (95% confidence interval [CI]) were late AMD 1.2 (0.8-1.5); and early AMD: grade 1 (soft distinct drusen or pigmentary irregularities), 39.3 (37.2-41.5); grade 2 (soft distinct drusen with pigmentary irregularities or soft indistinct or reticular drusen), 6.7 (5.8-7.6); and grade 3 (soft indistinct or reticular drusen with pigmentary irregularities), 0.2 (0.1-0.4). For ages 80 and older, the respective percent prevalence was: late AMD, 2.5 (0.4-4.7); and early AMD: grade 1, 43.1(35.7-50.6); grade 2, 8.1 (4.3-12.0); and grade 3, 0.5 (0-1.5). CONCLUSIONS The prevalence of early AMD (grades 1 and 2) is similar to that observed in Western populations, but grade 3 appears to be lower. The prevalence of late AMD is comparable to that in Western populations in the age group 60 to 79 years. It is likely that the prevalence in the 80 and older age group is underestimated.

Prevalence of Cataract in an Older Population in India: The India Study of Age-related Eye Disease

Purpose To describe the prevalence of cataract in older people in 2 areas of north and south India. Design Population-based, cross-sectional study. Participants Randomly sampled villages were enumerated to identify people aged ≥60 years. Of 7518 enumerated people, 78% participated in a hospital-based ophthalmic examination. Methods The examination included visual acuity measurement, dilatation, and anterior and posterior segment examination. Digital images of the lens were taken and graded by type and severity of opacity using the Lens Opacity Classification System III (LOCS III). Main Outcome Measures Age- and gender-standardized prevalence of cataract and 95% confidence intervals (CIs). We defined type of cataract based on the LOCS III grade in the worse eye of: ≥4 for nuclear cataract, ≥3 for cortical cataract, and ≥2 for posterior subcapsular cataract (PSC). Any unoperated cataract was based on these criteria or ungradable dense opacities. Any cataract was defined as any unoperated or operated cataract. Results The prevalence of unoperated cataract in people aged ≥60 was 58% in north India (95% CI, 56–60) and 53% (95% CI, 51–55) in south India (P = 0.01). Nuclear cataract was the most common type: 48% (95% CI, 46–50) in north India and 38% (95% CI, 37–40) in south India (P<0.0001); corresponding figures for PSC were 21% (95% CI, 20–23) and 17% (95% CI, 16–19; P = 0.003), respectively, and for cortical cataract 7.6% (95% CI, 7–9) and 10.2% (95% CI, 9–11; P<0.004). Bilateral aphakia/pseudophakia was slightly higher in the south (15.5%) than in the north (13.2%; P<0.03). The prevalence of any cataracts was similar in north (73.8%) and south India (71.8%). The prevalence of unoperated cataract increased with age and was higher in women than men (odds ratio [OR], 1.8). Aphakia/pseudophakia was also more common in women, either unilateral (OR, 1.2; P<0.02) or bilateral (OR, 1.3; P<0.002). Conclusions We found high rates of unoperated cataract in older people in north and south India. Posterior subcapsular cataract was more common than in western studies. Women had higher rates of cataract, which was not explained by differential access to surgery. Financial Disclosure(s) The authors have no proprietary or commercial interest in any of the materials discussed in this article.

Prevelence and Causes of Visual Impairment and Blindness in Older Adults in an Area of India with a High Cataract Surgical Rate

Background: The cataract surgical rate (CSR) in Gujarat, India is reported to be above 10,000 per million population. This study was conducted to investigate the prevalence and causes of vision impairment/blindness among older adults in a high CSR area. Methods: Geographically defined cluster sampling was used in randomly selecting persons ≥ 50 years of age in Navsari district. Subjects in 35 study clusters were enumerated and invited for measurement of presenting and best-corrected visual acuity and an ocular examination. The principal cause was identified for eyes with presenting visual acuity < 20/32. Results: A total of 5158 eligible persons were enumerated and 4738 (91.9%) examined. Prevalence of presenting visual impairment < 20/63 to 20/200 in the better eye was 29.3% (95% confidence interval [CI]: 27.5–31.2) and 13.5% (95% CI: 12.0–14.9) with best correction. The prevalence of presenting bilateral blindness (< 20/200) was 6.9% (95% CI: 5.7–8.1), and 3.1% (95% CI: 2.5–3.7) with best correction. Presenting and best-corrected blindness were both associated with older age and illiteracy; gender and rural/urban residence were not significant. Cataract in one or both eyes was the main cause of bilateral blindness (82.6%), followed by retinal disorders (8.9%). Cataract (50.3%) and refractive error (35.4%) were the main causes in eyes with vision acuity < 20/63 to 20/200, and refractive error (86.6%) in eyes with acuity < 20/32 to 20/63. Conclusions: Visual impairment and blindness is a significant problem among the elderly in Gujarat. Despite a reportedly high CSR, cataract remains the predominant cause of blindness.

Inverse Association of Vitamin C with Cataract in Older People in India

Objective To examine the association between vitamin C and cataract in the Indian setting. Design Population-based cross-sectional analytic study. Participants A total of 5638 people aged ≥60 years. Methods Enumeration of randomly sampled villages in 2 areas of north and south India to identify people aged ≥60 years. Participants were interviewed for socioeconomic and lifestyle factors (tobacco, alcohol, household cooking fuel, work, and diet); attended a clinical examination, including lens photography; and provided a blood sample for antioxidant analysis. Plasma vitamin C was measured using an enzyme-based assay in plasma stabilized with metaphosphoric acid, and other antioxidants were measured by reverse-phase high-pressure liquid chromatography. Main Outcome Measures Cataract and type of cataract were graded from digital lens images using the Lens Opacity Classification System III (LOCS III), and cataract was classified from the grade in the worse eye of ≥4 for nuclear cataract, ≥3 for cortical cataract, and ≥2 for posterior subcapsular cataract (PSC). Any cataract was defined as any unoperated or operated cataract. Results Of 7518 enumerated people, 5638 (75%) provided data on vitamin C, antioxidants, and potential confounders. Vitamin C was inversely associated with cataract (adjusted odds ratio [OR] for highest to lowest quartile = 0.61; 95% confidence interval (CI), 0.51–0.74; P=1.1×10−6). Inclusion of other antioxidants in the model (lutein, zeaxanthin, retinol, β-carotene, and α-tocopherol) made only a small attenuation to the result (OR 0.68; 95% CI, 0.57–0.82; P < 0.0001). Similar results were seen with vitamin C by type of cataract: nuclear cataract (adjusted OR 0.66; CI, 0.54–0.80; P < 0.0001), cortical cataract (adjusted OR 0.70; CI, 0.54–0.90; P < 0.002), and PSC (adjusted OR 0.58; CI, 0.45–0.74; P < 0.00003). Lutein, zeaxanthin, and retinol were significantly inversely associated with cataract, but the associations were weaker and not consistently observed by type of cataract. Inverse associations were also observed for dietary vitamin C and cataract. Conclusions We found a strong association with vitamin C and cataract in a vitamin C–depleted population. Financial Disclosure(s) The author(s) have no proprietary or commercial interest in any materials discussed in this article.

EPHA2 Polymorphisms and Age-Related Cataract in India

Objective We investigated whether previously reported single nucleotide polymorphisms (SNPs) of EPHA2 in European studies are associated with cataract in India. Methods We carried out a population-based genetic association study. We enumerated randomly sampled villages in two areas of north and south India to identify people aged 40 and over. Participants attended a clinical examination including lens photography and provided a blood sample for genotyping. Lens images were graded by the Lens Opacification Classification System (LOCS III). Cataract was defined as a LOCS III grade of nuclear ≥4, cortical ≥3, posterior sub-capsular (PSC) ≥2, or dense opacities or aphakia/pseudophakia in either eye. We genotyped SNPs rs3754334, rs7543472 and rs11260867 on genomic DNA extracted from peripheral blood leukocytes using TaqMan assays in an ABI 7900 real-time PCR. We used logistic regression with robust standard errors to examine the association between cataract and the EPHA2 SNPs, adjusting for age, sex and location. Results 7418 participants had data on at least one of the SNPs investigated. Genotype frequencies of controls were in Hardy-Weinberg Equilibrium (p>0.05). There was no association of rs3754334 with cataract or type of cataract. Minor allele homozygous genotypes of rs7543472 and rs11260867 compared to the major homozygote genotype were associated with cortical cataract, Odds ratio (OR) = 1.8, 95% Confidence Interval (CI) (1.1, 3.1) p = 0.03 and 2.9 (1.2, 7.1) p = 0.01 respectively, and with PSC cataract, OR = 1.5 (1.1, 2.2) p = 0.02 and 1.8 (0.9, 3.6) p = 0.07 respectively. There was no consistent association of SNPs with nuclear cataract or a combined variable of any type of cataract including operated cataract. Conclusions Our results in the Indian population agree with previous studies of the association of EPHA2 variants with cortical cataracts. We report new findings for the association with PSC which is particularly prevalent in Indians.

Epidemiological study of ocular trauma in an urban slum population in Delhi, India.

Purpose: To study the epidemiology and clinical profile of victims of ocular trauma in an urban slum population. Materials and Methods: This cross-sectional study, conducted on 500 families each in three randomly selected urban slums in Delhi, collected demographic data for all members of these families, and clinical data for all those who suffered ocular trauma at any time, that required medical attention. Data was managed on SPSS 11.0. Results: Of 6704 participants interviewed, 163 episodes of ocular trauma were reported by 158 participants (prevalence = 2.4%, confidence interval = 2.0 to 2.7) Mean age at trauma was 24.2 years. The association between the age of participants and the history of ocular trauma was significant (P < 0.001), when adjusted for sex, education and occupation. Males were significantly more affected. Blunt trauma was the commonest mode of injury (41.7%). Blindness resulted in 11.4% of injured eyes ( P = 0.028). Of 6704 participants, 1567 (23.4%) were illiterate, and no association was seen between education status and trauma, when adjusted for sex and age at injury. A significant association was noted between ocular trauma and workplace (Chi-square = 43.80, P < 0.001), and between blindness and place (Chi-square = 9.98, P = 0.041) and source (Chi-square = 10.88, P = 0.028) of ocular trauma. No association was found between visual outcome and the time interval between trauma and first consultation (Chi-square = 0.50, P = 0.78), between receiving treatment and the best corrected visual acuity (Chi-square = 0.81, P = 0.81), and between the person consulted and blinding ocular trauma (Chi-square = 1.88, P = 0.170). Conclusion: A significant burden of ocular trauma in the community requires that its prevention and early management be a public health priority.

Prevalence of Myopia and Its Risk Factors in Urban School Children in Delhi: The North India Myopia Study (NIM Study)

Purpose Assess prevalence of myopia and identify associated risk factors in urban school children. Methods This was a cross-sectional study screening children for sub-normal vision and refractive errors in Delhi. Vision was tested by trained health workers using ETDRS charts. Risk factor questionnaire was filled for children with vision <6/9.5, wearing spectacles and for a subset (10%) of randomly selected children with normal vision. All children with vision <6/9.5 underwent cycloplegic refraction. The prevalence of myopia <-0.5 diopters was assessed. Association of risk factors and prevalence of myopia was analyzed for children with myopia and randomly selected non myopic children and adjusted odds ratio values for all risk factors were estimated. Results A total number of 9884 children were screened with mean age of 11.6 + 2.2 years and 66.8% boys. Prevalence of myopia was 13.1% with only 320 children (24.7%) wearing appropriate spectacles. Mean myopic spherical error was -1.86 + 1.4 diopters. Prevalence of myopia was higher in private schools compared to government schools (p<0.001), in girls vs. boys (p = 0.004) and among older (> 11 years) children (p<0.001). There was a positive association of myopia with studying in private schools vs. government schools (p<0.001), positive family history (p< 0.001) and higher socio-economic status (p = 0.037). Positive association of presence of myopia was observed with children studying/reading > 5 hours per day (p < 0.001), watching television > 2 hours / day (p < 0.001) and with playing computer/video/mobile games (p < 0.001). An inverse association with outdoor activities/playing was observed with children playing > 2 hours in a day. Conclusion Myopia is a major health problem in Indian school children. It is important to identify modifiable risk factors associated with its development and try to develop cost effective intervention strategies.

Prevalence and vision-related outcomes of cataract surgery in Gujarat, India

Purpose: Investigate the prevalence and vision-related outcomes of cataract surgery in an area of high cataract surgical rate. Methods: Cluster sampling was used in randomly selecting individuals ≥ 50 years of age in 2007. Participants were queried regarding year and place of previous cataract surgery. Cataract surgical procedures and evidence of surgical complications were recorded. The principal cause was identified for eyes presenting with visual acuity (VA) ≤ 20/40. Results: A total of 4,738 persons were examined and 834 (17.6%) had cataract surgery. Intra-ocular lenses (IOLs) were used in 84.1% of the 1,299 cataract-operated eyes, with more than half of these having manual small incision surgery. Surgical coverage among the cataract blind (visual acuity [VA] < 20/200) was estimated as 72.2%. Coverage was associated with older age, literacy, and urban residence; gender was not significant. Among cataract-operated eyes, 18.7% presented with VA ≥ 20/32 and 18.0% were < 20/200. With best-corrected acuity, the corresponding percentages were 55.7% and 11.0%. Presenting and best-corrected VA ≥ 20/63 were associated with young age, literacy, and IOL surgery; urban residence and surgery in non-governmental organizations (NGO)/private facilities were also significant for presenting VA; and recent surgery was significant for best-corrected VA. Refractive error was the main cause of vision impairment/blindness in cataract-operated eyes. Conclusions: Refractive error and posterior capsule opacification, easily treatable causes of visual impairment, are common among the operated. A greater emphasis on the quality of visual acuity outcomes along with sustained efforts to provide access to affordable surgery is needed.

Prevalence and Risk Factors for Vitamin C Deficiency in North and South India: A Two Centre Population Based Study in People Aged 60 Years and Over

Background Studies from the UK and North America have reported vitamin C deficiency in around 1 in 5 men and 1 in 9 women in low income groups. There are few data on vitamin C deficiency in resource poor countries. Objectives To investigate the prevalence of vitamin C deficiency in India. Design We carried out a population-based cross-sectional survey in two areas of north and south India. Randomly sampled clusters were enumerated to identify people aged 60 and over. Participants (75% response rate) were interviewed for tobacco, alcohol, cooking fuel use, 24 hour diet recall and underwent anthropometry and blood collection. Vitamin C was measured using an enzyme-based assay in plasma stabilized with metaphosphoric acid. We categorised vitamin C status as deficient (<11 µmol/L), sub-optimal (11–28 µmol/L) and adequate (>28 µmol/L). We investigated factors associated with vitamin C deficiency using multivariable Poisson regression. Results The age, sex and season standardized prevalence of vitamin C deficiency was 73.9% (95% confidence Interval, CI 70.4,77.5) in 2668 people in north India and 45.7% (95% CI 42.5,48.9) in 2970 from south India. Only 10.8% in the north and 25.9% in the south met the criteria for adequate levels. Vitamin C deficiency varied by season, and was more prevalent in men, with increasing age, users of tobacco and biomass fuels, in those with anthropometric indicators of poor nutrition and with lower intakes of dietary vitamin C. Conclusions In poor communities, such as in our study, consideration needs to be given to measures to improve the consumption of vitamin C rich foods and to discourage the use of tobacco.