Retinal nerve fibre layer cross-sectional area, neuroretinal rim area and body mass index.

PURPOSE: To examine associations between body mass index, neuroretinal rim area and retinal nerve fibre layer cross-sectional area (RNFLCRA) in a population-based setting. METHODS: The Central India Eye and Medical Study is a population-based study performed in a rural region of Central India. The study included 4711 subjects (aged 30 + years). A detailed ophthalmic and medical examination was performed. Inclusion criteria for this study were an intra-ocular pressure ≤21 mmHg, open anterior chamber angles and an axial length ≤26.5 mm. Neuroretinal rim area and RNFLCRA were measured by confocal laser scanning tomography. RESULTS: The study included 3959 subjects fulfilling the inclusion criteria. Larger neuroretinal rim area (mean: 1.63 ± 0.32 mm(2) ) was significantly (p = 0.004) associated with a higher body mass index after adjusting for larger disc area (p < 0.001), younger age (p < 0.001), lower intraocular pressure (p < 0.001), and hyperopic refractive error (p < 0.001). Larger retinal nerve fibre layer cross-sectional area (mean:1.29 ± 0.39 mm(2) ) was significantly associated with higher body mass index (p = 0.001) after adjusting for younger age (p < 0.001), shorter axial length (p < 0.001), larger optic disc area (p < 0.001), taller body height (p < 0.001) and male gender (p = 0.04). CONCLUSIONS: In a rural Central Indian population, neuroretinal rim area and RNFLCRA as surrogates of the optic nerve fibres were related to a higher body mass index. Because body mass index is associated with cerebrospinal fluid pressure, the higher cerebrospinal fluid pressure may be associated with a larger neuroretinal rim area. It may vaguely point towards an association between cerebrospinal fluid pressure and glaucomatous optic neuropathy.

Prevalence of myelinated retinal nerve fibres in adult Indians: the Central India Eye and Medical Study.

PURPOSE: To determine the prevalence of myelinated retinal nerve fibers in the adult Indian population. METHODS: The Central India Eye and Medical Study performed in rural Central India included 4711 participants aged 30+ years. The participants underwent a detailed ophthalmic and medical examination. RESULTS: Readable fundus photographs were available for 8645 eyes of 4485 (95.2%) subjects. Myelinated retinal nerve fibers were detected in 52 eyes (46 subjects) with a prevalence rate of 0.58±0.08 per 100 eyes [95% confidence interval (CI): 0.42, 0.74] and 1.03±0.15 per 100 subjects (95%CI: 0.73, 1.32). Prevalence of myelinated retinal nerve fibers was significantly associated hyperopic refractive error (p=0.008; OR: 1.31; 95%CI: 1.07, 1.59). It was not significantly associated with age (p=0.11), best corrected visual acuity (logMAR; p=0.33), intraocular pressure (p=0.09), amount of nuclear cataract (p=0.93), optic disc area (p=0.60), presence of glaucomatous optic nerve atrophy (p=0.62), and early age-related macular degeneration (p=0.53). CONCLUSIONS: Myelinated retinal nerve fibers are present in about 10 out of 1000 adult Indians in rural Central India, with a higher prevalence in hyperopic eyes. Prevalence of myelinated retinal nerve fibers was not associated with age, visual acuity, glaucoma and macular degeneration.

Pseudoexfoliation: normative data and associations. The Central India Eye and Medical Study.

PURPOSE: To assess the prevalence of pseudoexfoliation (PEX) and its associations in a population-based setting. DESIGN: Population-based, cross-sectional study. METHODS: The Central India Eye and Medical Study included 4711 individuals. All study participants underwent a detailed ophthalmological examination. After medical pupil dilation, PEX was assessed by an experienced ophthalmologist using slit-lamp based biomicroscopy. RESULTS: Slit lamp examination results were available for 4646 (98.6%) study participants with a mean age of 49.3 ± 13.3 years (range: 30-100 years). PEX was detected in 87 eyes (prevalence: 0.95 ± 0.10% (95%CI: 0.75, 1.15) of 69 subjects (prevalence: 1.49 ± 0.18% (95%CI: 1.14, 1.83). PEX prevalence increased significantly (P<0.001) from 0% in the age group of 30-39 years, to 2.85 ± 0.56% in the age group of 60-69 years, to 6.60 ± 1.21% in the age group of 70-79 years, and to 12.3 ± 4.11% in the age group of 80+ years. In multivariate analysis, PEX prevalence was associated with higher age (P<0.001; regression coefficient B:0.11; odds ratio (OR): 1.11 (95%CI: 1.09, 1.13)), lower body mass index (P = 0.001; B: -0.12; OR: 0.88 (95CI: 0.82, 0.95)) and higher diastolic blood pressure (P = 0.002; B: 0.02; OR: 1.03 (95%CI: 1.01, 1.04)). In the multivariate analysis, PEX was not associated with retinal nerve fiber layer cross section area (P = 0.76) and presence of open-angle glaucoma (P = 0.15). CONCLUSIONS: In a rural Central Indian population aged 30+ years, PEX prevalence (mean: 1.49 ± 0.18%) was significantly associated with older age, lower body mass index and higher diastolic blood pressure. It was not significantly associated with optic nerve head measurements, refractive error, any ocular biometric parameter, nuclear cataract, early age-related macular degeneration and retinal vein occlusion, diabetes mellitus, smoking, and dyslipidemia.

Prevalence of optic disc hemorrhages in rural central India. The Central Indian Eye and Medical Study.

PURPOSE: To determine the frequency of optic disc hemorrhages in a rural Indian population. METHODS: The population-based Central Indian Eye and Medical Study included 4711 subjects. Mean age was 48.5±12.9 years (range: 30-100 years). Color optic disc photographs were examined. RESULTS: Optic disc photographs were available for 4570 (97.0%) subjects. Prevalence of disc hemorrhages was 17/8869 (0.19%; 95%CI:0.10,0.28) per eye and 16/4570 (0.35±0.09%; 95%CI:0.18,0.52) per subject. Prevalence of disc hemorrhages increased from 0.05% (95%CI:0.00,0.13) in the age group of 30-39 years to 0.25% (95CI:0.00,0.49) in the age group of 60-69 years and to 0.91% (95%CI:0.24,1.58) in the age group of 70+ years. After adjusting for older age, higher systolic blood pressure, diabetes mellitus, myopic refractive error, smaller neuroretinal rim area and thinner retinal nerve fiber layer, occurrence of disc hemorrhages was associated only with glaucomatous optic nerve damage (P<0.001; Odds ratio: 87; 95%CI:32,239). Eleven of the 17 (65%; 95%CI:39,90) disc hemorrhages were found in glaucomatous eyes. Out of 193 glaucomatous eyes, 11 eyes (5.7%; 95%CI:2.4,9.0) showed a disc hemorrhage. Out of the 8676 non-glaucomatous eyes, 6 eyes (0.07%; 95%CI:0.01,0.12) had an optic disc hemorrhage. CONCLUSIONS: Prevalence of disc hemorrhages (0.2% per eye; 0.4% per subject) in Indians aged 30+ years was strongly associated with glaucoma after adjustment for age, blood pressure and diabetes mellitus. A disc hemorrhage suggested glaucomatous optic nerve damage with a positive predictive value of 65%. About 6% of glaucomatous eyes showed a disc hemorrhage at the time of clinical examination highlighting the importance of optic disc hemorrhages for the diagnosis of glaucoma.

Prevalence and associated factors of glaucoma in rural central India. The Central India Eye and Medical Study.

PURPOSE: To assess the prevalence of glaucoma in rural Central India. METHODS: The population-based Central India Eye and Medical Study is a population-based study performed in a rural region of Central India. The study included 4711 subjects (aged 30+ years). A detailed ophthalmic and medical examination was performed. Glaucoma was defined by glaucomatous optic disc morphology, and in a second step, by the criteria of the International Society of Geographical and Epidemiological Ophthalmology (ISGEO). RESULTS: Optic disc photographs were available for 4570 (97.0%) subjects. Glaucoma was detected in 122 subjects (51 unilateral) (2.67% (95%CI: 2.20, 3.14). Glaucoma prevalence for the age groups of 30-39yrs, 40-49yrs, 50-59yrs, 60-69yrs, 70-79yrs, and 80+ years was 0.54% (95%CI: 0.11, 0.98), 1.03% (95%CI: 0.49, 1.57), 1.40% (95%CI: 0.58, 2.23), 6.62% (95%CI: 4.92, 8.31), 8.71% (95%CI: 5.55, 11.75), and 14.3% (95%CI: 4.13, 24.4), respectively. In multivariable analysis, glaucoma was associated with higher age (P<0.001), lower body mass index (P = 0.025), lower blood hemoglobin concentration (P = 0.03), higher intraocular pressure (P<0.001), disc hemorrhages (P<0.001), higher prevalence of myopic retinopathy (P<0.001), lower level of education (P = 0.03), longer axial length (P<0.001), thinner retinal nerve fiber layer (P<0.001), higher vertical cup/disc diameter ratio (P<0.001), and narrow anterior chamber angle (P = 0.02). Ratio of open-angle glaucoma to angle-closure glaucoma was 7.7:1 (1.93% (95%CI: 1.64, 2.22) to 0.24% (95%CI: 0.14, 0.34)). Using the ISGEO criteria, glaucoma prevalence was 2.8% (95%CI: 2.3, 3.3) with a less clear association with older age. CONCLUSIONS: Glaucoma prevalence in remote rural Central India is comparable to other regions. Associated factors were older age, lower body mass index, lower blood concentration of hemoglobin, lower level of education, higher intraocular pressure, disc hemorrhage, myopic retinopathy, and longer axial length. The ratio of open-angle glaucoma to angle-closure glaucoma was about 8:1.

Visual impairment and blindness in rural central India: the Central India Eye and Medical Study.

PURPOSE: The aim of the study was to investigate prevalence of visual impairment in rural central India. METHODS: The population-based Central India Eye and Medical Study included 4711 subjects with an age of 30+ years. Presenting visual acuity (PRVA) and best-corrected visual acuity (BCVA) were recorded. Visual impairment and blindness were defined using the World Health Organization (WHO) standard and United States (US) standard. RESULTS: On the basis of PRVA and using WHO and US standards, 1049 [22%; 95% confidence interval (CI): 21.1, 23.5] subjects and 1290 (27%; 95% CI: 26.1, 28.7) subjects, respectively, were visually impaired, and 35 (0.7%; 95% CI: 0.5, 1.0) subjects and 116 (2.5%; 95% CI: 2.0, 2.9) subjects, respectively, were blind. The corresponding age-standardized prevalence figures were 17%, 21%, 0.5% and 2%, respectively. Using best-correcting glasses could eliminate PRVA-visual impairment/blindness in 729 subjects (67% of all subjects with visual impairment/blindness). On the basis of BCVA and using WHO and US standards, 333 (7%; 95% CI: 6.3, 7.8) subjects and 473 (10%; 95% CI: 9.2, 10.9) subjects, respectively, had visual impairment, and 22 (0.5%; 95% CI: 0.3, 0.7) and 31 (0.7%; 95% CI: 0.4, 0.9) subjects, respectively, were blind. Corresponding age-standardized prevalence figures were 5%, 8%, 0.4% and 0.5%, respectively. Causes for BCVA-visual impairment/blindness were cataract (75%), postoperative posterior capsular opacification (4%), surgical complications (2%), corneal opacifications (2%), age-related macular degeneration (2%), other macular diseases (1%), and glaucoma (1%). CONCLUSIONS: Age-standardized prevalence of PRVA-visual impairment/blindness (WHO definition) in the adult population of rural central India was 17%. Most frequent cause was undercorrected refractive error. Supply of correct glasses is the most efficient way to improve vision in the rural central India.

Prevalence and associations of retinal vein occlusions: the Central India Eye and Medical Study.

PURPOSE: To determine the prevalence of retinal vein occlusions (RVOs) in rural central India. METHODS: The population-based Central India Eye and Medical Study was performed in rural central India and included 4,711 subjects (30 years and older). Using fundus photographs, we assessed the prevalence of branch retinal vein occlusions and central retinal vein occlusions. RESULTS: An RVO was detected in 38 eyes (0.42 ± 0.07%; 95% confidence interval: 0.29-0.56) of 35 subjects (0.76 ± 0.13%; 95% confidence interval: 0.50-1.01). Prevalence of branch retinal vein occlusions was 0.66% ± 0.12% per subject (95% confidence interval: 0.42%-0.90%) and of central retinal vein occlusions was 0.11% ± 0.05% per subject (95% confidence interval: 0.01%-0.21%). In binary logistic analysis, presence of RVOs was associated with higher age (P = 0.007), systolic blood pressure (P < 0.001), blood concentration of urea (P = 0.02), and narrower anterior chamber angle (P < 0.03). The RVO prevalence was not significantly (all Ps > 0.10) associated with body mass index; blood concentrations of glucose, cholesterol, high-density lipoproteins, and creatinine; presence of diabetes mellitus, tuberculosis and malaria; nutritional parameters; alcohol consumption; refractive error; and optic disk size. The age-specific prevalence rates of RVOs were 0.18% ± 0.13%, 0.29% ± 0.15%, 0.89% ± 0.34%, 1.07% ± 0.36%, 2.72% ± 0.85%, and 3.64% ± 2.55%, respectively, for decadal age groups. In two (5%) eyes, RVO had caused low vision (visual acuity <20/60 and ≥20/400). CONCLUSION: In the rural agrarian low-income population of Central India, RVOs were detected in 0.8% of adults, with branch retinal vein occlusions being approximately seven times more common than central retinal vein occlusions. Main associated factors were higher age, blood pressure, urea blood concentration, and narrow chamber angle. RVOs were no major reason for visual impairment.

Associations of early age-related macular degeneration with ocular and general parameters. The Central India Eyes and Medical Study.

PURPOSE: To assess associations between age-related macular degeneration (AMD) and ocular and general parameters. METHODS: The Central India Eye and Medical Study, a population-based study performed in rural Central India, included 4711 subjects (aged 30+ years) out of 5885 eligible subjects (response rate: 80.1%). Fundus photographs were assessed using the Wisconsin Age-Related Maculopathy Grading system. RESULTS: Fundus photographs were available for 4542 (96.4%) subjects. Early AMD was present in 215/4542 subjects (4.7 ± 0.3%), and late AMD was detected in 8/4542 (0.2 ± 0.03%) subjects. After adjustment for age, prevalence of AMD was significantly associated with hyperopic refractive error (p = 0.001), shorter axial length (p = 0.01), and higher corneal refractive power (p = 0.02). Each dioptre increase in hyperopic refraction or each millimetre decrease in axial length was associated with a 15% [odds ratio (OR):1.15; 95% confidence interval (CI): 1.06, 1.24] and 19% (OR: 0.81; 95%CI: 0.69, 0.95) increased probability of early AMD, respectively. AMD was not significantly associated with blood pressure, serum concentration of cholesterol, glycosylated haemoglobin Hb1Ac, high-density lipoproteins and postprandial glucose, gender, level of education, any parameter of smoking, alcohol consumption, psychiatric depression or of daily activities, anterior chamber depth, lens thickness, intraocular pressure, size of the optic disc, neuroretinal rim and parapapillary atrophy, nor amount of nuclear cataract and status after cataract surgery. If the statistical analysis was adjusted for age and refractive error, age-related macular degeneration was marginally significantly associated with a low intake of fruits (p = 0.06). CONCLUSIONS: Hyperopia (and short axial length) besides age was the single most important associated factor for AMD in adult Indians.

Anterior chamber depth and its associations with ocular and general parameters in adults.

BACKGROUND: To investigate the normative data of anterior chamber depth and its associations in adults in rural Central India. DESIGN: Population-based study. PARTICIPANTS: The Central India Eye and Medical Study included 4711 subjects aged 30+ years (response rate 80.1%). METHODS: The subjects underwent an ophthalmological examination including measurement of the anterior chamber depth by sonography. MAIN OUTCOME MEASURE: Anterior chamber depth. RESULTS: Mean anterior chamber depth was 3.22 ± 0.34 mm. In multivariate analysis, a shallow chamber depth was significantly associated with higher age (P < 0.001), female gender (P < 0.001), shorter body stature (P = 0.003), hyperopic refractive error (P < 0.001), higher lens thickness (P < 0.001) and shorter axial length (P < 0.001). CONCLUSIONS: In the rural Central Indian population, a shallow anterior chamber was associated with higher age, female gender, short body stature, hyperopia, thick lens and shorter axial length. Compared with population-based data from East Asia (China), the anterior chamber was markedly deeper in India. The data may be helpful to explain anatomic relationships of the anterior segment of the eye, to elucidate risk factors of angle-closure glaucoma and to explain ethnic differences in the prevalence of angle-closure glaucoma.

Prevalence of cataract surgery and postoperative visual outcome in rural central India Central India Eye and Medical Study.

PURPOSE: To determine the prevalence of cataract surgery and the postoperative visual outcomes in rural central India. SETTING: Villages in rural central India. DESIGN: Cohort study. METHODS: The population-based Central India Eye and Medical Study examined the prevalence of surgical pseudophakia/aphakia, the postoperative visual acuity, and the reasons for decreased postoperative vision in subjects aged 30+ in rural central India. Visual impairment was defined as (1) presenting visual acuity worse than 6/18 or (2) corrected distance visual acuity (CDVA) worse than 6/18. RESULTS: Of the 9392 eyes (99.7%) of 4711 subjects with available data on the lens status, 318 eyes (3.4%) (234 patients, 129 women) had had cataract surgery (5.0% ± 0.3%). Cataract surgery was significantly associated with age (P<.001), female sex (P = .008), shorter axial length (P<.001), and diabetes mellitus (P<.001). The prevalence of postoperative presenting visual impairment was 63% (201/318 eyes) and of postoperative CDVA impairment, 36% (117/318 eyes). The major cause of the former was incorrect intraocular lens (IOL) power (42%); the major causes of the latter were posterior capsule opacification (24%), surgical complications (21%), age-related macular degeneration (10.3%), other macular disorders (4.3%), corneal opacities (3.4%), and glaucoma (2.0%). Surgical complications were significantly more common in the aphakic group than in the pseudophakic group (46.4% versus 2.0%; P<.001). CONCLUSIONS: Approximately 5% of the central India population aged 30 years or older had had cataract surgery. Postoperative visual impairment was present in 2 of 3 eyes. The major reasons were incorrect IOL power and surgical complications. Improved IOL power calculations and improved surgical techniques may markedly improve postoperative outcome. FINANCIAL DISCLOSURE: No author has a financial or proprietary interest in any material or method mentioned.