Population-based assessment of sensitivity and specificity of a pinhole for detection of significant refractive errors in the community.

BACKGROUND: Measurements of refractive errors through subjective or automated refraction are not always possible in rapid assessment studies and community vision screening programs; however, measurements of vision with habitual correction and with a pinhole can easily be made. Although improvements in vision with a pinhole are assumed to mean that a refractive error is present, no studies have investigated the magnitude of improvement in vision with pinhole that is predictive of refractive error. The aim was to measure the sensitivity and specificity of 'vision improvement with pinhole' in predicting the presence of refractive error in a community setting. METHODS: Vision and vision with pinhole were measured using a logMAR chart for 488 of 582 individuals aged 15 to 50 years. Refractive errors were measured using non-cycloplegic autorefraction and subjective refraction. The presence of refractive error was defined using spherical equivalent refraction (SER) at two levels: SER greater than ± 0.50 D sphere (DS) and SER greater than ±1.00 DS. Three definitions for significant improvement in vision with a pinhole were used: 1. Presenting vision less than 6/12 and improving to 6/12 or better, 2. Improvement in vision of more than one logMAR line and 3. Improvement in vision of more than two logMAR lines. RESULTS: For refractive error defined as spherical equivalent refraction greater than ± 0.50 DS, the sensitivities and specificities for the pinhole test predicting the presence of refractive error were 83.9 per cent (95% CI: 74.5 to 90.9) and 98.8 per cent (95% CI: 97.1 to 99.6), respectively for definition 1. Definition 2 had a sensitivity 89.7 per cent (95% CI: 81.3 to 95.2) and specificity 88.0 per cent (95% CI: 4.4 to 91.0). Definition 3 had a sensitivity of 75.9 per cent (95% CI: 65.5 to 84.4) and specificity of 97.8 per cent (95% CI: 95.8 to 99.0). Similar results were found with spherical equivalent refraction greater than ±1.00 DS, when tested against the three pinhole-based definitions. CONCLUSION: Refractive error definitions based on improvement in vision with the pinhole shows good sensitivity and specificity at predicting the presence of significant refractive errors. These definitions can be used in rapid assessment surveys and community-based vision screenings.

Prevalence of spectacles use in Andhra Pradesh, India: rapid assessment of visual impairment project.

BACKGROUND: To assess the prevalence and patterns of spectacles use in South India state of Andhra Pradesh. DESIGN: A population-based cross sectional study. PARTICIPANTS: Seven thousand eight hundred subjects aged ≥40 years, sampled from one urban and two locations. METHODS: Two-stage cluster random sampling method was used to enumerate 7800 subjects. Distance visual acuity and near vision were assessed. A questionnaire was used to collect information on current and previous use of spectacles, spectacles providers and type of spectacles. Among those who discontinued use of spectacles, the reasons were elicited. MAIN OUTCOME MEASURES: The prevalence of spectacles use and spectacle coverage. RESULTS: In total, 7378/7800 subjects (95.0%) were examined. Among those examined, 53.6% were female, 49.5% of them aged between 40 and 49 years, and 62% of them had no education. The overall prevalence of spectacles use was 29.5% (95% confidence interval 28.5-30.4), 30.3% (95% confidence interval 29.0-31.6) in rural area compared with 27.9% (95% confidence interval 26.1-29.7) (P < 0.05) in urban location. Bifocals (72.8%) were the most common type of spectacles. Private eye clinics were the leading spectacles provider in all three regions. On applying multiple logistic regression, the odds of spectacles use increased with increasing age and were significantly higher for rural residents and those with higher levels of education. The spectacle coverage was 38.0% and 27% for refractive errors and presbyopia, respectively. CONCLUSIONS: Although prevalence of spectacles use is moderate, the spectacle coverage for both refractive errors and presbyopia is low. The strategies are required to improve the spectacle coverage in the region.

Changing trends in the prevalence of visual impairment, uncorrected refractive errors and use of spectacles in Mahbubnagar district in South India.

BACKGROUND/AIM: The Andhra Pradesh Eye disease Study (APEDS) was a conventional cross-sectional study conducted in four locations during 1996-2000. Ten years later, a Rapid Assessment of Refractive Errors (RARE) survey was conducted in one of the geographical regions. The prevalence of visual impairment (VI), uncorrected refractive error (URE), spectacles use obtained from both the surveys was compared. SETTINGS AND DESIGN: Rural settings; cross-sectional studies. MATERIALS AND METHODS: In both the surveys, distance visual acuity (VA) was assessed using a logMAR chart. Pinhole VA was assessed if presenting VA was <20/20 in APEDS and <20/40 in RARE. VI was defined as presenting VA <20/40 in the better eye. URE was defined as presenting VA <20/40 and improving to ≥20/40 with a pinhole. STATISTICAL ANALYSIS USED: Performed using Statistical Package for Social Sciences (SPSS). Chi square tests and t-test were used. RESULTS AND CONCLUSIONS: The results from a RARE survey with 3,095 subjects were compared with an APEDS dataset that had 1,232 subjects in the same age group of 15-49 years. The prevalence of VI has decreased from 9.5% (95% CI, 7.7-11.1) in APEDS to 2.7% (95% CI, 2.1-3.3) in RARE. Similarly, the prevalence of URE in the better eye decreased from 5.8% (95% CI, 4.5-7.1) to 2.3% (95% CI, 1.8-2.8). The usage of spectacles increased from 6.6% (95% CI, 5.2-8.0) to 9.7% (95% CI, 8.7-10.7). There is a decreasing trend in the prevalence of VI and URE in Mahbubnagar district in Andhra Pradesh over a decade.

Visual impairment in the South Indian state of Andhra Pradesh: Andhra Pradesh - rapid assessment of visual impairment (AP-RAVI) project.

PURPOSE: To assess the prevalence and causes of visual impairment in urban and rural population aged ≥ 40 years in the South India state of Andhra Pradesh. METHODS: A population based cross-sectional study was conducted in which 7800 subjects were sampled from two rural and an urban locations. Visual Acuity (VA) was assessed using a tumbling E chart and eye examinations were performed by trained vision technicians. A questionnaire was used to collect personal and demographic information and previous consultation to eye care providers. Blindness and moderate Visual Impairment (VI) was defined as presenting VA <6/60 and <6/18 to 6/60 in the better eye respectively. VI included blindness and moderate VI. RESULTS: Of the 7800 subjects enumerated, 7378 (94.6%) were examined. Among those examined, 46.4% were male and 61.8% of them had no education. The mean age of those examined (51.7 years; standard deviation 10.9 years) was similar to those not examined (52.8 years; standard deviation 9.9 years) (p=0.048). Age and gender adjusted prevalence of VI was 14.3% (95% CI: 13.5-15.0). Refractive errors were the leading cause of VI accounting for 47.6% of all VI followed by cataract (43.7%). Together, they contributed to over 91.3% of the total VI. With multiple logistic regression, the odds of having VI increased significantly with increasing age. Those respondents who had no education were twice (95% CI: 1.7-2.5) more likely to have VI compared to those who were educated. VI was associated with rural residence (OR: 1.3; 95% CI: 1.1-1.6). The association between VI and gender was not statistically significant. CONCLUSIONS: The visual impairment remains a public health challenge in Andhra Pradesh, most of which can be addressed with relatively straight forward interventions like cataract surgery and spectacles. The eye care services need to be streamlined to address this challenge.

Presbyopia, spectacles use and spectacle correction coverage for near vision among cloth weaving communities in Prakasam district in South India.

PURPOSE: To assess the prevalence of presbyopia, spectacles use and spectacle correction coverage for near vision among weaving communities in Prakasam district in the South Indian state of Andhra Pradesh. METHODS: A population based cross sectional study was conducted among a population aged ≥40 years. Distance visual acuity was assessed at 6 m. Near vision was assessed using N notation charts at a fixed distance of 40 cm. Presbyopia was defined as binocular unaided near vision

Visual impairment among weaving communities in Prakasam district in South India.

PURPOSE: To assess the prevalence and causes of visual impairment in weaving communities in Prakasam district in South India state of Andhra Pradesh. METHODS: Using Rapid Assessment of Visual Impairment (RAVI) methodology, a population based cross-sectional study was conducted. A two-stage sampling strategy was used to select 3000 participants aged ≥40 years. Visual Acuity (VA) was assessed using a tumbling E chart and ocular examinations were performed by trained Para medical ophthalmic personnel. A questionnaire was used to collect personal and demographic information. Blindness and moderate Visual Impairment (VI) was defined as presenting VA <6/60 and <6/18 to 6/60 respectively. VI included blindness and moderate VI. RESULTS: 2848 of 3000 enumerated subjects (94.0%) participated. 39% were in 40-49 years age group and 11.8% were aged ≥70 years, 55% were women and nearly half of them had no formal education. 400 (14%; 95% CI: 12.8-15.3) subjects had VI, including blindness in 131 (4.6%; 95% CI: 3.8-5.4) and moderate VI in 269 (9.4%; 95% CI: 8.3-10.5) individuals. On applying multiple logistic regression, VI was significantly associated with older age and no formal education. Though the odds of having VI were higher in females, it was of borderline statistical significance (p = 0.06). Refractive error was the leading cause of all VI followed by cataract (56%). However, refractive errors were the leading cause of moderate VI (73.2%) and cataract was the leading cause of blindness (62.6%). 'Cannot afford the cost of services' was the leading barrier for utilization of eye care services (47%). CONCLUSIONS: There is a significant burden of VI in weaving communities in Andhra Pradesh, India most of which is avoidable. With this information as baseline, services need to be streamlined to address this burden.

Refractive error in children in a rural population in India.

PURPOSE: To assess the prevalence of refractive error and related visual impairment in school-aged children in the rural population of the Mahabubnagar district in the southern Indian state of Andhra Pradesh. METHODS: Random selection of village-based clusters was used to identify a sample of children 7 to 15 years of age. From April 2000 through February 2001, children in the 25 selected clusters were enumerated in a door-to-door survey and examined at a rural eye center in the district. The examination included visual acuity measurements, ocular motility evaluation, retinoscopy and autorefraction under cycloplegia, and examination of the anterior segment, media, and fundus. Myopia was defined as spherical equivalent refractive error of at least -0.50 D and hyperopia as +2.00 D or more. Children with reduced vision and a sample of those with normal vision underwent independent replicate examinations for quality assurance in seven clusters. RESULTS: A total of 4414 children from 4876 households was enumerated, and 4074 (92.3%) were examined. The prevalence of uncorrected, baseline (presenting), and best corrected visual acuity of 20/40 or worse in the better eye was 2.7%, 2.6%, and 0.78%, respectively. Refractive error was the cause in 61% of eyes with vision impairment, amblyopia in 12%, other causes in 15%, and unexplained causes in the remaining 13%. A gradual shift toward less-positive values of refractive error occurred with increasing age in both boys and girls. Myopia in one or both eyes was present in 4.1% of the children. Myopia risk was associated with female gender and having a father with a higher level of schooling. Higher risk of myopia in children of older age was of borderline statistical significance (P = 0.069). Hyperopia in at least one eye was present in 0.8% of children, with no significant predictors. CONCLUSIONS: Refractive error was the main cause of visual impairment in children aged between 7 and 15 years in rural India. There was a benefit of spectacles in 70% of those who had visual acuity of 20/40 or worse in the better eye at baseline examination. Because visual impairment can have a significant impact on a child's life in terms of education and development, it is important that effective strategies be developed to eliminate this easily treated cause of visual impairment.