Gudlavalleti Venkata Satyanarayana Murthy

A population-based eye survey of older adults in a rural district of Rajasthan: II. Outcomes of cataract surgery☆

PURPOSE To assess the outcomes of cataract surgery in rural northwest India. DESIGN Population-based, cross-sectional study. PARTICIPANTS A total of 549 cataract-operated persons (723 operated eyes). METHODS Cluster sampling was used in randomly selecting a cross-sectional sample of persons 50 years of age or older for visual acuity measurement, refraction, and slit-lamp and direct ophthalmoscope examination early in 1999. Those operated on for cataract were queried as to the date and place of surgery. The principal cause of reduced vision was identified for all examined eyes with presenting visual acuity worse than 6/18. MAIN OUTCOME MEASURES Presenting and best-corrected visual acuity and cause of vision loss. RESULTS Presenting visual acuity was less than 6/60 in the better eye in 33.7% of cataract-operated persons and greater than or equal to 6/18 in both eyes in 8.2%; 31.7% were bilaterally operated on. Of cataract-operated eyes, 44.1% initially had visual acuity less than 6/60 and 31.5% greater than or equal to 6/18; with best correction, the corresponding percentages were 14.0% and 61.5%. Intracapsular cataract extraction was used in 92% of cases, and 66% had been operated on in surgery camps. Surgical complications were common and a major cause of vision impairment. In multiple logistic regression modeling, female gender and residence in a rural area were associated negatively with both presenting and best-corrected visual acuity outcomes, and surgery conducted before 1990 was associated negatively with best-corrected visual acuity. Place of surgery and subject schooling were not associated with vision outcomes. CONCLUSIONS Cataract surgery subjects in rural areas of India that are without adequately equipped facilities and skilled surgeons, and lack of availability of intraocular lenses, are not realizing the full sight-restoring potential of modern-day surgery. Emphasis on the quality of cataract surgery outcomes must be increased to keep pace with that being given to increasing surgical volume.

A population-based eye survey of older adults in a rural district of Rajasthan: I. Central vision impairment, blindness, and cataract surgery

PURPOSE To assess the prevalence of central vision blindness and cataract surgery in older adults in rural northwest India. DESIGN Population-based, cross-sectional study. PARTICIPANTS A total of 4284 examined persons 50 years of age or older. METHODS A random selection of village-based clusters was used to identify a population sample in the predominantly rural Bharatpur district of Rajasthan. Eligible subjects in the 25 selected clusters were enumerated through a door-to-door household survey and invited to village sites for visual acuity testing and eye examination early in 1999. The principal cause of reduced central vision was identified for eyes that had visual acuity worse than 6/18. Independent replicate testing for quality assurance monitoring took place in participants with reduced vision and in a sample of those with normal vision in five of the study clusters. MAIN OUTCOME MEASURES Presenting and best-corrected visual acuity and lens status. RESULTS A total of 4728 eligible persons in 2821 households were enumerated, and 4284 (90.6%) were examined. The prevalence of presenting and best-corrected visual acuity worse than 6/60 in both eyes was 11.9% (95% confidence interval: 10.0%-13.9%) and 6.1% (95% CI: 4.7%-7.4%), respectively. Presenting blindness was associated with increasing age, female gender, lack of schooling, and rural residence. Cataract was the principal cause of blindness in one or both eyes in 67.5% of blind persons, with uncorrected aphakia and other refractive error affecting 18.4% in at least one eye. The prevalence of cataract surgery was 12.8% (95% CI: 11.6%-14.0%), with an estimated 65.7% of the cataract blind operated on; low surgical coverage was associated with lack of schooling. CONCLUSIONS Blindness, particularly blindness because of cataract, continues to be a significant problem among the elderly living in remote areas of rural northwest India. Increased attention should be given to reaching women and the illiterate.

Causes of blindness and visual impairment in Nigeria: the Nigeria national blindness and visual impairment survey.

PURPOSE Determine causes of blindness and visual impairment among adults aged >or=40 years. METHODS Multistage, stratified, cluster random sampling with probability proportional to size procedures were used to identify a nationally representative sample of 15,027 persons >or=40 years of age. Distance vision was measured with a reduced logMAR tumbling E-chart. Clinical examination included a basic eye examination of all subjects and a more detailed examination of those who had presenting vision <6/12 in either eye. Cause for vision loss was assigned to all subjects with presenting vision <6/12 in any eye. RESULTS Of the 15,122 persons aged >or=40 years who were enumerated, 13,599 (89.9%) were examined. In 84%, blindness was avoidable. Uncorrected refractive errors were responsible for 57.1% of moderate (<6/18-6/60) visual impairment. Cataract (43%) was the commonest cause of blindness (<3/60). Prevalence of cataract-related blindness was 1.8% (95% CI: 1.57-2.05) and glaucoma-related blindness was 0.7% (95% CI: 0.55-0.88). Increasing age was associated with increasing prevalence of all major blinding conditions. Females, illiterate persons, and residents in the North East geopolitical zone had significantly higher odds of cataract-induced blindness and severe visual impairment. CONCLUSIONS The high proportion of avoidable blindness, with half being attributable to cataract alone and uncorrected refractive errors being responsible for 57% of moderate visual impairment, means that appropriate and accessible refraction and surgical services need to be provided. If priority attention is not given, the number of blind and severely visually impaired adults in Nigeria will increase by >40% over the next decade.

Causes and temporal trends of blindness and severe visual impairment in children in schools for the blind in North India

Aims: To describe the causes of severe visual impairment and blindness (SVI/BL) in children in schools for the blind in north India, and explore temporal trends in the major causes. Methods: A total of 703 children were examined in 13 blind schools in Delhi. A modified WHO/PBL eye examination record for children with blindness and low vision which included sections on visual acuity, additional non-ocular disabilities, onset of visual loss, the most affected anatomical part of the eye concerning visual impairment, and the aetiological category of the child’s disorder based on the timing of insult leading to visual loss was administered in all children. Results: With best correction, 22 (3.1%) were severely visually impaired (visual acuity in the better eye of <6/60) and 628 (89.3%) children were blind (visual acuity in the better eye of <3/60). Anatomical sites of SVI/BL were whole globe in 27.4% children, cornea 21.7%, retina 15.1%, and lens 10.9%. The underlying cause of visual loss was undetermined in 56.5% children (mainly abnormality since birth 42.3% and cataract 8.3%), childhood disorders were responsible in 28.0% (mainly vitamin A deficiency/measles 20.5%), and hereditary factors were identified in 13.4%. Study of temporal trends of SVI/BL by comparing causes in children in three different age groups—5–8 years, 9–12 years, and 13–16 years—suggests that retinal disorders have become more important while childhood onset disorders (particularly vitamin A deficiency) have declined. Conclusions: Almost half of the children suffered from potentially preventable and/or treatable conditions, with vitamin A deficiency/measles and cataract the leading causes. Retinal disorders seem to be increasing in importance while childhood disorders have declined over a period of 10 years.

Rapid Assessment of Avoidable Blindness in India

Background Rapid assessment of avoidable blindness provides valid estimates in a short period of time to assess the magnitude and causes of avoidable blindness. The study determined magnitude and causes of avoidable blindness in India in 2007 among the 50+ population. Methods and Findings Sixteen randomly selected districts where blindness surveys were undertaken 7 to 10 years earlier were identified for a follow up survey. Stratified cluster sampling was used and 25 clusters (20 rural and 5 urban) were randomly picked in each district.. After a random start, 100 individuals aged 50+ were enumerated and examined sequentially in each cluster. All those with presenting vision <6/18 were dilated and examined by an ophthalmologist. 42722 individuals aged > = 50 years were enumerated, and 94.7% examined. Based on presenting vision,, 4.4% (95% Confidence Interval[CI]: 4.1,4.8) were severely visually impaired (vision<6/60 to 3/60 in the better eye) and 3.6% (95% CI: 3.3,3.9) were blind (vision<3/60 in the better eye). Prevalence of low vision (<6/18 to 6/60 in the better eye) was 16.8% (95% CI: 16.0,17.5). Prevalence of blindness and severe visual impairment (<6/60 in the better eye) was higher among rural residents (8.2%; 95% CI: 7.9,8.6) compared to urban (7.1%; 95% CI: 5.0, 9.2), among females (9.2%; 95% CI: 8.6,9.8) compared to males (6.5%; 95% CI: 6.0,7.1) and people above 70 years (20.6%; 95% CI: 19.1,22.0) compared to people aged 50–54 years (1.3%; 95% CI: 1.1,1.6). Of all blindness, 88.2% was avoidable. of which 81.9% was due to cataract and 7.1% to uncorrected refractive errors/uncorrected aphakia. Conclusions Cataract and refractive errors are major causes of blindness and low vision and control strategies should prioritize them. Most blindness and low vision burden is avoidable.

Blood levels of vitamin C, carotenoids and retinol are inversely associated with cataract in a north Indian population

PURPOSE To examine the association of blood antioxidants with cataract. METHODS Cross-sectional study of people aged >or=50 years identified from a household enumeration of 11 randomly sampled villages in North India. Participants were interviewed for putative risk factors (tobacco, alcohol, biomass fuel use, sunlight exposure, and socioeconomic status) and underwent lens photography and blood sampling. Lens photographs (nuclear, cortical, and posterior subcapsular) were graded according to the Lens Opacities Classification System (LOCS II). Cataract was defined as LOCS II grade >or=2 for any opacity or ungradable, because of dense opacification or history of cataract surgery. People without cataract were defined as LOCS II <2 on all three types of opacity, with absence of previous surgery. RESULTS Of 1443 people aged >or=50 years, 94% were interviewed, 87% attended an eye examination, and 78% gave a blood sample; 1112 (77%) were included in the analyses. Compared with levels in Western populations, antioxidants were low, especially vitamin C. Vitamin C was inversely associated with cataract. Odds ratios (OR) for the highest (>or=15 micromol/L) compared with the lowest (<or=6.3 micromol/L) tertile were 0.64, (95% confidence interval [CI] 0.48-0.85; P < 0.01). Tertiles of zeaxanthin (P < 0.03), alpha-carotene (P < 0.05), and retinol (P < 0.02) were associated with decreased odds of cataract. In analysis of continuous data, significant inverse associations were found for vitamin C, zeaxanthin, lutein, lycopene, alpha- and beta-carotene, and beta-cryptoxanthin, but not for alpha- or gamma-tocopherol. CONCLUSIONS Inverse associations were found between cataract and blood antioxidants in an antioxidant-depleted study sample.

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.

The development of the Indian vision function questionnaire: field testing and psychometric evaluation

Objective: To develop and evaluate the acceptability, reliability, validity, and responsiveness of the Indian vision function questionnaire (IND-VFQ). Methods: Problem statements from previous qualitative studies were reduced to a 45 item interviewer administered questionnaire representing three a priori domains (general functioning, psychosocial impact, and visual symptoms) which was evaluated in patients with cataract (n = 420), glaucoma (n = 120), diabetic retinopathy, or age related macular degeneration (n = 120) and normal controls (n = 120). Standard methods were used for item reduction and to evaluate psychometric properties. Results: Psychometric item reduction produced a 33 item questionnaire. Psychometric evaluation showed that two of the three scales (psychosocial impact and visual symptoms) had good acceptability, and that all three scales showed high internal consistency (alpha >0.80; item-total correlations 0.54–0.86) and test-retest reliability (>0.89). All three scales showed moderate evidence of convergent and discriminant validity. Responsiveness, assessed in cataract patients (n = 120) before and after surgery, was good for all three scales (effect sizes >1). Conclusions: The IND-VFQ33 is a psychometrically sound measure of vision function addressing a gap in patient defined measures of vision function developed in populations living in low income countries.

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.