Vinay Nangia

Prevalence and associations of keratoconus in rural Maharashtra in Central India: the Central India Eye and Medical Study.

PURPOSE To evaluate the prevalence and associated factors of keratoconus in the adult Indian population. DESIGN Population-based study. METHODS The Central India Eye and Medical Study is a population-based study performed in a rural region close to Nagpur in Central India. It included 4,711 subjects (aged 30 years and above) out of 5,885 eligible subjects (response rate, 80.1%). The participants underwent a detailed ophthalmic and medical examination. This study was focused on the prevalence of keratoconus, defined as an anterior corneal refractive power exceeding 48 diopters (D). RESULTS Out of the 4,711 subjects, corneal refractive power measurements were available for 4,667 subjects (99.1%). Keratoconus was detected in 212 eyes (2.3%) of 128 subjects (prevalence rate, 2.3% +/- 0.2%). In multivariate analysis, the presence of keratoconus was significantly associated with lower body height (P < .001), lower level of education (P= .03), higher myopic refractive error (P = .004), and thinner central corneal thickness (P = .006). It was not significantly associated with alcohol consumption (P = .99) or smoking (P = .08) nor with questions relating to the psychiatric status. Defining a keratoconus as corneal refractive power of > or =49 D or of > or =50 D, a keratoconus was detected in 58 eyes (0.6%) and 10 eyes (0.1%), respectively. CONCLUSIONS Keratoconus defined as corneal refractive power of 48+ D has a prevalence of 2.3% +/- 0.2% among Indians aged 30 years and above and living in the rural region of Central India. The prevalence of keratoconus was associated with lower body height, lower level of education, myopic refractive error, and thinner central cornea.

Prevalence, Awareness, Control, and Associations of Arterial Hypertension in a Rural Central India Population: The Central India Eye and Medical Study

BACKGROUND Because relatively little has been known about the actual prevalence of hypertension in India, particularly for its rural population, we investigated the prevalence of arterial hypertension in a rural Indian population. METHODS The Central India Eye and Medical Study is a population-based study in a rural Central Indian region. It included 4,711 subjects (ages 30+ years) undergoing an ophthalmic and medical examination. Hypertension was defined as systolic blood pressure > or =140 mm Hg and/or diastolic blood pressure > or =90 mm Hg, and/or self-reported current treatment for hypertension. RESULTS Arterial hypertension was found in 1,041 (22.1%) subjects. Its prevalence was associated with higher age (P < 0.001), higher body mass index (P < 0.001), body height (P = 0.001), higher blood hemoglobin levels (P < 0.001), and elevated blood urea concentration (P = 0.008). It was not significantly associated with gender, level of education, family income, kind of daily physical activities, type of diet, and serum concentrations of cholesterol and creatinine. Among the hypertensive study participants (n = 1,041), 208 (20.0%) subjects were aware of their disease. A current antihypertensive treatment was reported by 84 subjects of the 1,041 arterial hypertensive subjects (8.1 +/- 0.9%). Out of the treated subjects, 24 (29%) had abnormally high diastolic blood pressure measurements and 44 (52%) participants had abnormally high systolic blood pressure measurements. CONCLUSIONS In a rural Central Indian population of ages 30+ years, the prevalence of arterial hypertension was 22.1 +/- 0.6% with an awareness rate of 20% and a treatment rate of 8%. The low awareness and treatment rate may demand increasing public health efforts.

Ocular Axial Length and Its Associations in an Adult Population of Central Rural India: The Central India Eye and Medical Study

PURPOSE To investigate the normal distribution of axial length of the globe, which is a major measurement of the eye, and its associations with other ocular and systemic parameters. DESIGN Population-based study. PARTICIPANTS The Central India Eye and Medical Study is a population-based study performed in a rural region of central India. The study comprised 4711 subjects (aged 30+ years) of 5885 eligible individuals (response rate, 80.1%). METHODS A detailed ophthalmic and medical examination was performed. The axial length was measured sonographically. MAIN OUTCOME MEASURES Axial length. RESULTS Axial length measurements were available on 4698 study participants (99.7%). Their mean age was 49.4+/-13.4 years (range, 30-100 years), and the mean refractive error was -0.18+/-1.48 diopters (range, -20.0 to +7.25 diopters). Mean axial length was 22.6+/-0.91 mm (range, 18.22-34.20 mm). In multivariate analysis, axial length was significantly (P<0.001) associated with the systemic parameters of increased age, taller body height, greater body mass index, and higher level of education, and with the ocular parameters of lower best-corrected visual acuity, lower corneal refractive power, deeper anterior chamber, thicker lens, and more myopic spherical power and cylindrical refractive power. Within the highly myopic group, as defined by an axial length that exceeded 26.5 mm, none of these associations (except for the association between axial length and spherical refractive power) were statistically significant (P>0.15) in univariate or multivariate analysis. CONCLUSIONS In a rural population of central India, the mean ocular axial length was 22.6+/-0.91 mm, which was shorter than that of other populations. Axial length was associated with the systemic parameters of increased age, taller body height, greater body mass index, and a higher level of education, and with the ocular parameters of lower best-corrected visual acuity, lower corneal refractive power, deeper anterior chamber, thicker lens, and more myopic spherical and cylindrical refractive power. These associations were valid only for those eyes that were not highly myopic, whereas axial length was associated with refractive error only in highly myopic eyes. FINANCIAL DISCLOSURE(S) Proprietary or commercial disclosure may be found after the references.

Central Corneal Thickness and Its Association with Ocular and General Parameters in Indians: The Central India Eye and Medical Study

PURPOSE To evaluate the distribution of central corneal thickness (CCT) and its associations in an adult Indian population. DESIGN Population-based study. PARTICIPANTS The Central India Eye and Medical Study is a population-based study performed in a rural region close to Nagpur in Central India; it included 4711 subjects (ages 30+ years) of 5885 eligible subjects (response rate, 80.1%). METHODS The participants underwent a detailed ophthalmic and medical examination, including 200 standardized questions on socioeconomic background, lifestyle, social relations, and psychiatric depression. This study was focused on CCT as measured by sonography and its associations. Intraocular pressure was measured by applanation tonometry. MAIN OUTCOME MEASURES Central corneal thickness and intraocular pressure. RESULTS Central corneal thickness measurement data were available on 9370 (99.4%) eyes. Mean CCT was 514+/-33 microm (median, 517 microm; range, 290-696 microm). By multiple regression analysis, CCT was associated significantly with younger age (P<0.001), male gender (P<0.001), higher body mass index (P = 0.006), lower corneal refractive power (P<0.001), deeper anterior chamber (P = 0.02), thicker lens (P = 0.02), and shorter axial length (P = 0.006). Central corneal thickness was not associated significantly with refractive error (P = 0.54) or cylindrical refractive error (P = 0.20). If eyes with a corneal refractive power of 45 or more diopters were excluded, the relationship between CCT and axial length was no longer statistically significant (P>0.05), whereas all other relationships remained significant. Intraocular pressure readings increased significantly (P<0.001) with both higher CCT and higher corneal refractive power. CONCLUSIONS Indians from rural Central India have markedly thinner corneas than do Caucasians or Chinese, and, as in other populations, CCT is greater in men. CCT was associated with younger age, higher body mass index, lower corneal refractive power, deeper anterior chamber, thicker lens, and shorter axial length. Intraocular pressure readings were associated with CCT, with high readings in those eyes that had thick corneas or steep corneas. Central corneal thickness and steepness of the anterior corneal surface may thus both have to be taken into account when applanation tonometry is performed. FINANCIAL DISCLOSURE(S) The author(s) have no proprietary or commercial interest in any materials discussed in this article.

Trans-Lamina Cribrosa Pressure Difference and Open-Angle Glaucoma. The Central India Eye and Medical Study

PURPOSE To assess associations of the trans-lamina cribrosa pressure difference (TLCPD) with glaucomatous optic neuropathy. METHODS The population-based Central India Eye and Medical Study included 4711 subjects. Based on a previous study with lumbar cerebrospinal fluid pressure (CSFP) measurements, CSFP was calculated as CSFP[mmHg] = 0.44 Body Mass Index[kg/m2]+0.16 Diastolic Blood Pressure[mmHg]-0.18×Age[Years] -1.91. TLCPD was IOP-CSFP. RESULTS Mean TLCPD was 3.64±4.25 mm Hg in the non-glaucomatous population and 9.65±8.17 mmHg in the glaucomatous group. In multivariate analysis, TLCPD was associated with older age (P<0.001; standardized coefficient beta:0.53; regression coefficient B:0.18; 95% confidence interval (CI):0.17, 0.18), lower body mass index (P<0.001; beta: -0.28; B: -0.36; 95%CI: -0.38, -0.31), lower diastolic blood pressure (P<0.001; beta: -0.31; B: -0.12; 95%CI: -0.13, -0.11), higher pulse (P<0.001; beta:0.05; B:0.02; 95%CI:0.01,0.2), lower body height (P = 0.02; beta: -0.02; B: -0.01; 95%CI: -0.02,0.00), higher educational level (P<0.001; beta:0.04; B:0.15; 95%CI:0.09,0.22), higher cholesterol blood concentrations (P<0.001; beta:0.04; B:0.01; 95%CI:0.01,0.01), longer axial length (P = 0.006; beta:0.03; B:0.14; 95%CI:0.04,0.24), thicker central cornea (P<0.001; beta:0.15; B:0.02; 95%CI:0.02,0.02), higher corneal refractive power (P<0.001; beta:0.07; B:0.18; 95%CI:0.13,0.23) and presence of glaucomatous optic neuropathy (P<0.001; beta:0.11; B:3.43; 95%CI:2.96,3.99). Differences between glaucomatous subjects and non-glaucomatous subjects in CSFP were more pronounced for open-angle glaucoma (OAG) than for angle-closure glaucoma (ACG) (3.0 mmHg versus 1.8 mmHg), while differences between glaucomatous subjects and non-glaucomatous subjects in IOP were higher for ACG than for OAG (8.5 mmHg versus 3.0 mmHg). Presence of OAG was significantly associated with TLCPD (P<0.001; OR:1.24; 95%CI:1.19,1.29) but not with IOP (P = 0.08; OR:0.96; 95%CI:0.91,1.00). Prevalence of ACG was significantly associated with IOP (P = 0.04; OR:1.19; 95%CI:1.01,1.40) but not with TLCPD (P = 0.92). CONCLUSIONS In OAG, but not in ACG, calculated TLCPD versus IOP showed a better association with glaucoma presence and amount of glaucomatous optic neuropathy. It supports the notion of a potential role of low CSFP in the pathogenesis of open-angle glaucoma.

Refractive error in Central India: the Central India Eye and Medical Study.

OBJECTIVE To evaluate the refractive error and its associations in the adult population of rural Central India. DESIGN Population-based study. PARTICIPANTS The Central India Eye and Medical Study is a population-based study performed in a markedly rural region in Central India. It included 4711 subjects (aged 30 years or older) of 5885 eligible subjects (response rate, 80.1%). METHODS The participants underwent a detailed ophthalmic and medical examination, including standardized questions on the socioeconomic background, lifestyle, and social relations. This study was focused on the refractive error, the prevalence of hyperopia and myopia, and its factors. MAIN OUTCOME MEASURES Refractive error. RESULTS After exclusion of pseudophakic or aphakic eyes, 9076 (96.3%) eyes of 4619 (98.0%) subjects (2472 females) were included into the study. The mean refractive error was -0.20+/-1.51 diopters (D). Myopia of more than -0.50 D, -1.0 D, more than -6.0 D, and more than -8 D occurred in 17.0+/-0.6%, 13.0+/-0.5%, 0.9+/-1.4%, and 0.4+/-0.1% of the subjects, respectively. Hyperopia of more than 0.50 D was detected in 18.0+/-0.6% of the subjects. Refractive error was associated significantly (i.e., became more hyperopic) with lower age (P<0.001), lower best-corrected visual acuity (P<0.001), lower corneal refractive power (P<0.001), and shorter axial length (P<0.001). In multivariate analysis, refractive error was not significantly associated with the level of education (P = 0.56). High myopia (>-8 D) was associated significantly with male gender (P = 0.03) and lower best-corrected visual acuity (P<0.001). Mean anisometropia was 0.41+/-1.02 D. It was associated significantly with age (P<0.001), myopic refractive error (P<0.001), and lower best-corrected visual acuity (P<0.001). The mean astigmatic error was 0.29+/-0.60 D and was associated significantly with higher age (P<0.001), level of education (P = 0.01), lower best-corrected visual acuity (P<0.001), and higher corneal refractive power (P<0.001). CONCLUSIONS The rural population of Central India has not experienced a myopic shift as described for many urban populations at the Pacific Rim. Correspondingly, the relatively low level of education was not associated with myopia. Urbanization may be a major factor for myopization. FINANCIAL DISCLOSURE(S) Proprietary or commercial disclosure may be found after the references.

Prevalence and Risk Factors for Age-Related Macular Degeneration in Indians: A Comparative Study in Singapore and India

PURPOSE To compare the prevalence and risk factors for age-related macular degeneration (AMD) in 2 Indian populations, 1 living in urban Singapore and 1 in rural central India. DESIGN Population-based, cross-sectional studies of Indians aged 40+ years. METHODS Our analysis included 3337 Singapore-residing participants and 3422 India-residing participants. All participants underwent comprehensive systemic and ocular examinations and retinal photography. AMD was graded from retinal photographs according to the Wisconsin Age-Related Maculopathy Grading System. Systemic and ocular risk factors were assessed for association with AMD. RESULTS Singapore-residing participants were older (mean age 57.8 years vs 53.8 years) and, after adjusting for age and sex, were more likely to have previous cataract surgery, higher body mass index, hypertension, diabetes, previous myocardial infarction, higher cholesterol, and lower creatinine levels, but less likely to be current smokers, than India-residing participants. The age-standardized prevalence of early and late AMD was 4.45% and 0.34%, respectively, in Singapore and 5.80% and 0.16%, respectively, in India. Shorter axial length was associated with early AMD in both Singapore and India, whereas previous cataract surgery, higher body mass index, hypertension, and lower cholesterol were associated with early AMD in Singapore but not in India. CONCLUSION The prevalence of AMD was similar among Indian adults living in urban Singapore and rural India, despite differences in cardiovascular risk factor profile and demographics.

Optic disc size in a population‐based study in central India: the Central India Eye and Medical Study (CIEMS)

Purpose:  To determine optic disc size and its associations in an adult population in central India.

Intraocular pressure and associated factors: the central India eye and medical study.

PurposeTo determine the range of intraocular pressure (IOP) in a rural Central Indian population and to evaluate existing and identify potential new ocular, medical, and socioeconomic factors associated with IOP. MethodsThis is a population-based study carried out in Nagpur in Central India. A single IOP measurement was taken using Goldmann applanation tonometry and population IOP was described using standard descriptive statistics. ResultsOf 5885 eligible patients, 9338 eyes of 4686 patients were included in the study. The mean IOP was 13.6±3.4 mm Hg (median: 14 mm Hg; range: 2 to 56 mm Hg). In multivariate regression analysis, the following factors, with correlation coefficients (r) and P values reported in parenthesis, were found to be associated with IOP. Ocular factors included higher corneal power (0.12; P=0.004), lower central corneal thickness (0.02; P<0.001), and higher myopic refractive power (−0.13; P=0.001). Medical factors included diastolic blood pressure (0.05; P<0.001), pulse rate (0.02; P=0.005), and body mass index (0.05; P=0.01). Socioeconomic factors included level of education (0.15; P=0.05) and livestock ownership (−0.18; P=0.008). ConclusionLow mean IOP was found when compared with other epidemiologic studies and this may be explained by the low central corneal thickness found in the study population. Several known ocular and medical factors and new socioeconomic factors were found to be associated with IOP. Identifying risk factors associated with IOP in different populations may allow clinicians to better define and recognize subgroups of patients at risk of elevated IOP. Newly identified socioeconomic-IOP associations will need to be validated in future studies.

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.