Search

Purpose To report 15-year incidence rate of visual loss (blindness and visual impairment [VI]), causes, and risk factors for participants in Andhra Pradesh Eye Disease Study III (APEDS III). Design Population-based cohort study. Methods From 2012 to 2016, all rural participants were interviewed and underwent a comprehensive eye examination, including dilated fundus examination and imaging. Presenting visual acuity (PVA) and best-corrected visual acuity (BCVA) were measured using a standard logarithm of Minimum Angle of Resolution chart at 3 meters. World Health Organization (WHO) and United States of America (USA) categories of VI and blindness were used. Incident visual loss was defined as the development of or worsening of visual loss of one or more categories. Results In APEDS I, 7,771 rural participants were examined using stratified, random-cluster systematic sampling; in APEDS III, 5,395 participants (69.4% of rural or 52.4% of total participants) were re-examined. Using WHO categories, the crude incidence rate of any visual loss based on PVA and BCVA were 14.6 (95% confidence interval [CI]:13.6-15.7) and 6.3 (95% CI: 6.1-6.4) per 100 person-years, respectively. Using USA criteria, the values were 22.6 (95% CI: 22.3-23.0) and 10.6 (95% CI: 10.3-10.8) per 100 person-years, respectively. More than 90% of visual loss was attributable to cataract and uncorrected refractive error. Using WHO categories, significant independent risk factors for the incident visual loss were increasing age, female gender, illiteracy, past or current smoker, and current use of alcohol. Using the USA definition, an additional risk factor was lower level of education. Conclusions The high incidence likely reflects poor access to eye care in this population, which needs to be taken into account when planning eye care programs.

Purpose To report 15-year incidence rate and associated risk factors of pterygium among people aged 30 years and above at baseline in the rural clusters of longitudinal Andhra Pradesh Eye Disease Study (APEDS III). Methods The baseline APEDS I included 7771 participants of which 6447 (83%) were traced and 5395 (83.7%) were re-examined in APEDS III. To estimate the incidence of pterygium, we selected participants who were 30 years and above at baseline (4188), of which 2976 were traced and 2627 (88.3%) were examined, and based on inclusion criteria, 2290 participants were included in the study. The incidence rate of pterygium was defined as the proportion of people free of pterygium at baseline who had developed the condition at 15-year follow-up (range 13–17 years). Univariate and multivariable analyses for risk factors were undertaken. Results The sex-adjusted incidence rate of pterygium was 25.2 per 100 person-years (95% CI 24.8 to 25.7) which was significantly higher for men than women (26.3 per 100 person-years (95% CI 25.6 to 27.0) and 24.7 (95% CI 24.1 to 25.3) respectively). At the multivariable analysis, male gender (RR: 1.35, 95% CI 1.0 to 1.83), no formal education (RR: 2.46, 95% CI 1.22 to 4.93), outdoor occupation (RR: 1.47, 95% CI 1.14 to 1.9) and lower body mass index (BMI) ( Conclusions The overall incidence rate of pterygium was high in this rural population, especially in men and those engaged in outdoor activities, lack of formal education and with lower BMI. It is likely that greater exposure to ultraviolet light is a major contributing factor, thus warranting preventive strategies.

Background Color vision has been consistently shown to be unaffected in animals that are raised in dark or in color-deprived environments. However, there are only a few studies that directly addressed the effect of congenital visual deprivation in color perception in humans. Objective The goal of the current study was to assess the effect of congenital visual deprivation on color vision using a panel based color arrangement test. Methods We investigated the recovery of color vision using the Farnsworth D15 test in a group of individuals who had experienced visual deprivation since birth due to bilateral dense congenital cataracts before undergoing cataract-reversal surgery (Congenital cataract, CC, n = 12). In addition, we tested two groups of control participants: (1) individuals who had had non-dense congenital cataract or developed cataract later in their childhood (Developmental cataract, DC, n = 10), and (2) sighted controls with normal or corrected to normal vision (n = 14). Based on the methods proposed by Vingrys and King-Smith (1988), we derived the following metrics of color vision performance: (1) total error score, (2) confusion index, (3) confusion angle, and (4) selectivity index. Results All of the measured indices of color vision performance were unaltered by a period of congenital visual deprivation. Conclusions Our results support the view that, development of visual functions such as color discrimination and color arrangement does not depend on typical visual experience during a sensitive phase in early childhood.

Purpose To report on the 15-year incidence of primary angle closure disease (PACD) among participants aged ≥40 years in rural southern India Design Population-based longitudinal incidence rate study Methods Setting: 3 rural study centres. Study population: Phakic participants aged ≥40 years who participated in both examination time points. Observation procedures: All participants at the baseline and at the mean 15-year follow-up visit underwent a detailed interview, anthropometry, blood pressure measurement, and comprehensive eye examination. Automated perimetry was attempted based on predefined criteria. Main outcome measures included development of any form of PACD, as defined by the International Society for Geographical and Epidemiological Ophthalmology (ISGEO), during the follow-up period in phakic participants, who did not have the disease at baseline. Results We analyzed data obtained from 1,197 (81.4% out of available 1,470) participants to calculate the incidence of the disease. The mean age (standard deviation) of the study participants at the baseline was 50.2 (8.1) years, with 670 male (45.5%) and 800 female (54.4%) participants. The incidence rate per 100 person-years (95% confidence interval) for primary angle closure suspect, primary angle closure, and primary angle closure glaucoma was 8.8 (8.4, 9.2), 6.2 (5.9, 6.6), and 1.6 (1.4, 1.8), respectively. Thus, the incidence of all forms of PACD was 16.4 (15.9, 17) per 100 person-years. On logistic regression analysis, female gender was a significant risk factor whereas presence of myopia was protective. Conclusions This study reports long-term incidence of PACD from rural India. It has implications for eye health care policies, strategies, and planning.

Primary congenital glaucoma (PCG) is a severe autosomal recessive ocular disorder associated with considerable clinical and genetic heterogeneity. Recently, rare heterozygous alleles in the angiopoietin receptor-encoding gene TEK were implicated in PCG. We undertook this study to ascertain the second mutant allele in a large cohort (n = 337) of autosomal recessive PCG cases that carried heterozygous TEK mutations. Our investigations revealed 12 rare heterozygous missense mutations in TEK by targeted sequencing. Interestingly, four of these TEK mutations (p.E103D, p.I148T, p.Q214P, and p.G743A) co-occurred with three heterozygous mutations in another major PCG gene CYP1B1 (p.A115P, p.E229K, and p.R368H) in five families. The parents of these probands harbored either of the heterozygous TEK or CYP1B1 alleles and were asymptomatic, indicating a potential digenic mode of inheritance. Furthermore, we ascertained the interactions of TEK and CYP1B1 by co-transfection and pull-down assays in HEK293 cells. Ligand responsiveness of the wild-type and mutant TEK proteins was assessed in HUVECs using immunofluorescence analysis. We observed that recombinant TEK and CYP1B1 proteins interact with each other, while the disease-associated allelic combinations of TEK (p.E103D)::CYP1B1 (p.A115P), TEK (p.Q214P)::CYP1B1 (p.E229K), and TEK (p.I148T)::CYP1B1 (p.R368H) exhibit perturbed interaction. The mutations also diminished the ability of TEK to respond to ligand stimulation, indicating perturbed TEK signaling. Overall, our data suggest that interaction of TEK and CYP1B1 contributes to PCG pathogenesis and argue that TEK-CYP1B1 may perform overlapping as well as distinct functions in manifesting the disease etiology.

Humans preferentially match arbitrary words containing higher- and lower-frequency phonemes to angular and smooth shapes, respectively. Here, we investigated the role of visual experience in the development of audiovisual and audiohaptic sound–shape associations (SSAs) using a unique set of five groups: individuals who had suffered a transient period of congenital blindness through congenital bilateral dense cataracts before undergoing cataract-reversal surgeries (CC group), individuals with a history of developmental cataracts (DC group), individuals with congenital permanent blindness (CB group), individuals with late permanent blindness (LB group), and controls with typical sight (TS group). Whereas the TS and LB groups showed highly robust SSAs, the CB, CC, and DC groups did not—in any of the modality combinations tested. These results provide evidence for a protracted sensitive period during which aberrant vision prevents SSA acquisition. Moreover, the finding of a systematic SSA in the LB group demonstrates that representations acquired during the sensitive period are resilient to loss despite dramatically changed experience.

To assess the prevalence and causes of unilateral visual impairment (VI) in the South Indian state of Andhra Pradesh.A population-based cross-sectional study was conducted among individuals aged ≥40 years in one urban and two rural locations, using rapid assessment methodology. A 2-stage cluster random sampling method was used to select 7800 individuals from 156 clusters. Distance visual acuity (VA) was assessed using a standard Snellen chart at a distance of 6 m. Eye examinations were conducted using a torchlight and distance direct ophthalmoscopy. Unilateral VI was defined as presenting VA6/18 in one eye and presenting VA ≥6/18 in the other, and included moderate unilateral VI (6/18 to 6/60) and unilateral blindness (6/60).In total, 7378 individuals (94.6%) were examined. After excluding 918 individuals with VI in the better eye, data were analyzed for the remaining 6460 individuals. Among those included in the analysis, mean age was 50 years (standard deviation 9.6 years), 46.7% were male, 58.9% had no education, and 34.1% were urban residents. The prevalence of unilateral VI was 11.3% (95% confidence interval 10.5-12.1%; n = 730). Uncorrected refractive error was found to be the leading cause (44%; n = 321) of unilateral VI followed by cataract (39.7%; n = 290).Unilateral VI is common in the South Indian state of Andhra Pradesh. As most of this VI can be addressed with interventions such as cataract surgery and spectacles, service models need to be streamlined to address this need.

The rationale, objectives, study design and procedures for the longitudinal Andhra Pradesh Eye Disease Study are described.A longitudinal cohort study was carried out.Participants include surviving cohort from the rural component of Andhra Pradesh Eye Disease Study.During 1996-2000, Andhra Pradesh Eye Disease Survey was conducted in three rural (n = 7771) and one urban (n = 2522) areas (now called Andhra Pradesh Eye Disease Study 1). In 2009-2010, a feasibility exercise (Andhra Pradesh Eye Disease Study 2) for a longitudinal study (Andhra Pradesh Eye Disease Study 3) was undertaken in the rural clusters only, as urban clusters no longer existed. In Andhra Pradesh Eye Disease Study 3, a detailed interview will be carried out to collect data on sociodemographic factors, ocular and systemic history, risk factors, visual function, knowledge of eye diseases and barriers to accessing services. All participants will also undergo a comprehensive eye examination including photography of lens, optic disc and retina, Optic Coherence Tomography of the posterior segment, anthropometry, blood pressure and frailty measures.Measures include estimates of the incidence of visual impairment and age-related eye disease (lens opacities, glaucoma and age-related macular degeneration) and the progression of eye disease (lens opacities and myopia) and associated risk factors.Of the 7771 respondents examined in rural areas in Andhra Pradesh Eye Disease Study 1, 5447 (70.1%) participants were traced in Andhra Pradesh Eye Disease Study 2. These participants will be re-examined.Andhra Pradesh Eye Disease Study 3 will provide data on the incidence and progression of visual impairment and major eye diseases and their associated risk factors in India. The study will provide further evidence to aid planning eye care services.