ORCID Profile
0000-0002-8467-5544
Current Organisations
Aravind Eye Care System
,
Centre for Eye Research Australia
,
University of Melbourne
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Publisher: Medknow
Date: 05-2023
Publisher: Medknow
Date: 2023
Publisher: BMJ
Date: 06-09-2023
Publisher: Medknow
Date: 2019
Publisher: American Medical Association (AMA)
Date: 07-2019
Publisher: Springer Science and Business Media LLC
Date: 29-07-2022
DOI: 10.1038/S41433-022-02190-4
Abstract: To validate the fundus image grading results by a trained grader (Non-ophthalmologist) and an ophthalmologist grader for detecting diabetic retinopathy (DR) and diabetic macular oedema (DMO) against fundus examination by a retina specialist (gold standard). A prospective diagnostic accuracy study was conducted using 2002 non-mydriatic colour fundus images from 1001 patients aged ≥40 years. Using the Aravind Diabetic Retinopathy Evaluation Software (ADRES) images were graded by both a trained non-ophthalmologist grader (grader-1) and an ophthalmologist (grader-2). Sensitivity, specificity, positive predictive value and negative predictive value were calculated for grader-1 and grader-2 against the grading results by an independent retina specialist who performed dilated fundus examination for every study participant. Out of 1001 patients included, 42% were women and the mean ± (SD) age was 55.8 (8.39) years. For moderate or worse DR, the sensitivity and specificity for grading by grader-1 with respect to the gold standard was 66.9% and 91.0% respectively and the same for the ophthalmologist was 83.6% and 80.3% respectively. For referable DMO, grader-1 and grader-2 had a sensitivity of 74.6% and 85.6% respectively and a specificity of 83.7% and 79.8% respectively. Our results demonstrate good level of accuracy for the fundus image grading performed by a trained non-ophthalmologist which was comparable with the grading by an ophthalmologist. Engaging trained non-ophthalmologists potentially can enhance the efficiency of DR diagnosis using fundus images. Further study with multiple non-ophthalmologist graders is needed to verify the results and strategies to improve agreement for DMO diagnosis are needed.
Publisher: Elsevier BV
Date: 2022
Publisher: Wiley
Date: 25-03-2018
DOI: 10.1111/OPO.12447
Abstract: To investigate prevalence and risk factors for myopia, hyperopia and astigmatism in southern India. Randomly s led villages were enumerated to identify people aged ≥40 years. Participants were interviewed for socioeconomic and lifestyle factors and attended a hospital‐based ophthalmic examination including visual acuity measurement and objective and subjective measurement of refractive status. Myopia was defined as spherical equivalent ( SE ) worse than −0.75 dioptres (D), hyperopia as SE ≥+1D and astigmatism as cylinder −0.5. The age‐standardised prevalences of myopia, hyperopia and astigmatism were 35.6% (95% CI : 34.7–36.6), 17.0% (95% CI : 16.3–17.8) and 32.6 (29.3–36.1), respectively. Of those with myopia ( n = 1490), 70% had advanced cataract. Of these, 79% had presenting visual acuity ( VA ) less than 6/18 and after best correction, 44% of these improved to 6/12 or better and 27% remained with VA less than 6/18. In multivariable analyses (excluding patients with advanced cataract), increasing nuclear opacity score, current tobacco use, and increasing height were associated with higher odds of myopia. Higher levels of education were associated with increased odds of myopia in younger people and decreased odds in older people. Increasing time outdoors was associated with myopia only in older people. Increasing age and female gender were associated with hyperopia, and nuclear opacity score, increasing time outdoors, rural residence and current tobacco use with lower odds of hyperopia. After controlling for myopia, factors associated with higher odds of astigmatism were age, rural residence, and increasing nuclear opacity score and increasing education with lower odds. In contrast to high‐income settings and in agreement with studies from low‐income settings, we found a rise in myopia with increasing age reflecting the high prevalence of advanced cataract.
Publisher: Springer Science and Business Media LLC
Date: 30-01-2018
Publisher: Elsevier BV
Date: 12-2021
DOI: 10.1016/J.OPHTHA.2021.05.030
Abstract: To compare patient preferences for eyeglasses prescribed using a low-cost, portable wavefront autorefractor versus standard subjective refraction (SR). Randomized, cross-over clinical trial. Patients aged 18 to 40 years presenting with refractive errors (REs) to a tertiary eye hospital in Southern India. Participants underwent SR followed by autorefraction (AR) using the monocular version of the QuickSee device (PlenOptika Inc). An independent optician, masked to the refraction approach, prepared eyeglasses based on each refraction approach. Participants (masked to refraction source) were randomly assigned to use SR- or AR-based eyeglasses first, followed by the other pair, for 1 week each. At the end of each week, participants had their vision checked and were interviewed about their experience with the eyeglasses. Patients preferring eyeglasses were chosen using AR and SR. The 400 participants enrolled between March 26, 2018, and August 2, 2019, had a mean (standard deviation) age of 28.4 (6.6) years, and 68.8% were women. There was a strong correlation between spherical equivalents using SR and AR (r = 0.97, P 0.05 for all). We observed a strong agreement between the prescriptions from SR and AR, and eyeglasses prescribed using SR and AR were equally preferred by patients. Wider use of prescribing based on AR alone in resource-limited settings is supported by these findings.
Publisher: Informa UK Limited
Date: 26-09-2013
Publisher: Cold Spring Harbor Laboratory
Date: 04-01-2023
DOI: 10.1101/2023.01.01.23284101
Abstract: Eye care programs, in developing countries, are often planned using the cataract surgical rate (CSR) targets - retrospectively estimated from Rapid Assessment (RAAB) surveys. A limitation of this approach is that it ignores the annual overall eye care requirements for a given population. Moreover, targets set are arbitrary, often influenced by capacity rather than need. To address this lacunae, we implemented a novel study design to estimate the annual need for comprehensive eye care in a 1.2 million population. We conducted a population-based longitudinal study in Theni district, Tamil Nadu, India. All permanent residents of all ages were included. We conducted the study in three phases, (i) household-level enumeration and enrolment, (ii) basic eye examination (BEE) at household one-year post-enrolment, and (iii) assessment of eye care utilization and full eye examination (FEE) at central locations. All people aged 40 and above were invited to the FEE. Those aged less than 40 years were invited to the when FEE if indicated. We conducted three pilot studies to test the study and clinical examination protocols. In the main study we enrolled 24,327 subjects (58% aged below 40 years and 42% aged 40 years and above). Of those less than 40 years, 72% completed the BEE, of whom 20% were referred for FEE and 70% of people aged ≥40 years underwent a comprehensive eye examination at central location. Our study design provides appropriate long-term public health intervention planning, resource allocation, efficient delivery of care, and designing of eye care services for resource-limited settings.
Publisher: Public Library of Science (PLoS)
Date: 03-08-2022
DOI: 10.1371/JOURNAL.PONE.0272451
Abstract: To assess the accuracy of refraction measurements by ClickCheck TM compared with the standard practice of subjective refraction at a tertiary level eye hospital. Diagnostic accuracy trial. All participants, recruited consecutively, underwent auto-refraction (AR) and subjective refraction (SR) followed by refraction measurement using ClickCheck TM (CR) by a trained research assistant. Eyeglass prescriptions generated using ClickCheck TM and the resulting visual acuity (VA) was compared to SR for accuracy. Inter-rater reliability and agreement were determined using Intra-class correlation and Bland Altman analysis respectively. The 1,079 participants enrolled had a mean (SD) age of 39.02 (17.94) years and 56% were women. Overall, 45.3% of the participants had refractive error greater than ±0.5D. The mean (SD) spherical corrections were -0.66D (1.85) and -0.89D (2.20) in SR and CR respectively. There was high level of agreement between the spherical power measured using SR and CR (ICC: 0.940 (95% CI: 0.933 to 0.947). For the assessment of cylindrical correction, there was moderate level of agreement between SR and CR (ICC: 0.493 (0.100 to 0.715). There was moderate level of agreement between the VA measurements performed by using corrections from SR and CR (ICC: 0.577 (95% CI: 0.521–0.628). The subgroup analysis based on the age categories also showed high level of agreement for spherical corrections between the two approaches (ICC: 0.900). Bland Altman analysis showed good agreement for spherical corrections between SR and CR (Mean difference: 0.224D 95% LoA: -1.647 D to 2.096 D) without evidence of measurement bias. There was a high level of agreement for spherical power measurement between CR and SR. However, improvements are needed in order to accurately assess the cylindrical power. Being a portable, low-cost and easy-to-use refraction device, ClickCheck TM can be used for first level assessment of refractive errors, thereby enhancing the efficiency of refractive services, especially in low- and-middle-income countries.
Publisher: Cold Spring Harbor Laboratory
Date: 13-08-2018
DOI: 10.1101/390625
Abstract: To assess the quality of eyeglass prescriptions provided by an affordable wavefront autorefractor operated by a minimally-trained technician in a low-resource setting. 708 participants were recruited from consecutive patients registered for routine eye examinations at Aravind Eye Hospital in Madurai, India, or an affiliated rural satellite vision centre. Visual acuity (VA) and patient preference were compared for eyeglasses prescribed from a novel wavefront autorefractor versus eyeglasses prescribed from subjective refraction by an experienced refractionist. Mean ± standard deviation VA was 0.30 ± 0.37, −0.02 ± 0.14, and −0.04 ± 0.11 LogMAR units before correction, with autorefractor correction, and with subjective refraction correction, respectively (all differences P 0.01). Overall, 25% of participants had no preference, 33% preferred eyeglasses from autorefractor prescriptions, and 42% preferred eyeglasses from subjective refraction prescriptions ( P 0.01). Of the 438 patients 40 years old and younger, 96 had no preference and the remainder had no statistically-significant difference in preference for subjective refraction prescriptions (51%) versus autorefractor prescriptions (49%) ( P = 0.52). Average VAs from autorefractor-prescribed eyeglasses were one letter worse than those from subjective refraction. More than half of all participants either had no preference or preferred eyeglasses prescribed by the autorefractor. This marginal difference in quality may warrant autorefractor-based prescriptions, given the portable form-factor, short measurement time, low-cost, and minimal training required to use the autorefractor evaluated here. Eyeglass prescriptions can be accurately measured by a minimally-trained technician using a low-cost wavefront autorefractor in rural India. Objective refraction may be a feasible approach to increasing eyeglass accessibility in low-resource settings.
Publisher: Medknow
Date: 2011
Publisher: Elsevier BV
Date: 07-2021
Publisher: Informa UK Limited
Date: 19-03-2013
DOI: 10.3109/09286586.2013.766756
Abstract: To investigate patterns and characteristics of men and women who used different cataract surgery payment streams in a South Indian hospital. We randomly s led patients with age-related cataract aged 40 years and over from three routine cataract surgical service streams: walk-in paying, walk-in subsidized and free c . Presenting visual acuity (VA) and cataract surgical details were obtained from routine hospital records. Demographic and socioeconomic factors were collected from patient interviews. Multiple logistic regression was used to investigate factors associated with use of different streams with walk-in paying as the reference group. There were 7076 eligible admissions (3742 women and 3334 men). Proportionately more women than men attended the walk-in subsidized (56%) or free c sections (55%) compared to the walk-in paying stream (42%, odds ratio, OR, 1.40 95% confidence interval, CI, 1.25-1.57 and OR 1.33 95% CI 1.19-1.49, respectively). After adjustment for socioeconomic factors (illiteracy, not being in paid work), rural residence and poor presenting VA, OR for women compared to men for the walk-in subsided stream was 1.02, (95% CI 0.87-1.18) and for the free c 0.94 (95% CI 0.80-1.11). Our results indicate that women are underrepresented in the paying section, reflecting their poorer socioeconomic and educational statuses.
Publisher: Georg Thieme Verlag KG
Date: 08-12-2017
Location: United Kingdom of Great Britain and Northern Ireland
Location: India
Start Date: 2012
End Date: 2015
Funder: Wellcome Trust
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