A new look at the WHOQOL as health-related quality of life instrument among visually impaired people using Rasch analysis.

PURPOSE: To examine the psychometric characteristics of the World Health Organization quality of life instrument-modified Indian version (modified WHOQOL) and its subscales in adults with visual impairment (VI) using Rasch analysis. METHODS: Cross-sectional data were of people aged ≥40 years with VI (n = 1,333) who responded to the modified WHOQOL in the Andhra Pradesh Eye Disease Study, India. Rasch analysis was used to explore the instrument and its subscales for key indices such as measurement precision by person separation reliability, PSR (i.e., discrimination between strata of participants' health-related QOL [HRQOL], recommended minimum value 0.8), unidimensionality (i.e., measurement of a single construct), and targeting (i.e., matching of item difficulty to participants' HRQOL). RESULTS: Rasch-guided iterative approach including category re-organization to enable threshold ordering and item deletion to overcome multidimensionality resulted in a unidimensional 9-item WHOQOL and a 6-item level of independence (LOI) subscale with adequate PSR (0.81 and 0.82, respectively). Targeting was sub-optimal for both (-1.58 logits for WHOQOL and -2.55 logits for the subscale). Remaining subscales were dysfunctional. CONCLUSIONS: The WHOQOL and LOI subscale can be improved and shortened, and the Rasch-revised versions are likely to assess the HROQL of VI patients best because of their brevity, reliability, and unidimensionality.

Prevalence and risk factors for refractive errors in the South Indian adult population: The Andhra Pradesh Eye disease study.

AIM: To report the prevalence, risk factors and associated population attributable risk percentage (PAR) for refractive errors in the South Indian adult population. METHODS: A population-based cross-sectional epidemiologic study was conducted in the Indian state of Andhra Pradesh. A multistage cluster, systematic, stratified random sampling method was used to obtain participants (n = 10293) for this study. RESULTS: The age-gender-area-adjusted prevalence rates in those >/=40 years of age were determined for myopia (spherical equivalent [SE] < -0.5 D) 34.6% (95% confidence interval [CI]: 33.1-36.1), high-myopia (SE < -5.0 D) 4.5% (95% CI: 3.8-5.2), hyperopia (SE > +0.5 D) 18.4% (95% CI: 17.1-19.7), astigmatism (cylinder < -0.5 D) 37.6% (95% CI: 36-39.2), and anisometropia (SE difference between right and left eyes >0.5 D) 13.0% (95% CI: 11.9-14.1). The prevalence of myopia, astigmatism, high-myopia, and anisometropia significantly increased with increasing age (all p < 0.0001). There was no gender difference in prevalence rates in any type of refractive error, though women had a significantly higher rate of hyperopia than men (p < 0.0001). Hyperopia was significantly higher among those with a higher educational level (odds ratio [OR] 2.49; 95% CI: 1.51-3.95) and significantly higher among the hypertensive group (OR 1.24; 95% CI: 1.03-1.49). The severity of lens nuclear opacity was positively associated with myopia and negatively associated with hyperopia. CONCLUSIONS: The prevalence of myopia in this adult Indian population is much higher than in similarly aged white populations. These results confirm the previously reported association between myopia, hyperopia, and nuclear opacity.

Ocular trauma in a rural population of southern India: the Andhra Pradesh Eye Disease Study.

OBJECTIVE: To determine the prevalence of ocular trauma and proportion of blindness and visual impairment due to ocular trauma in a rural population of southern India. DESIGN: Population-based cross-sectional epidemiological study. PARTICIPANTS: A total of 7771 subjects of all ages, representative of the rural population of Andhra Pradesh. METHODS: The subjects underwent a detailed interview and comprehensive ocular evaluation as part of the population-based Andhra Pradesh Eye Disease Study. MAIN OUTCOME: An eye was considered to be blind due to trauma if best-corrected distance visual acuity was worse than 6/60 and the cause was attributed to ocular trauma. RESULTS: A total of 824 (10.6%) subjects gave a history of ocular trauma in either eye, including 76 (1.0%) persons reporting trauma in both eyes. The overall age- and gender-adjusted prevalence of history of eye injury in this rural population was 7.5% (95% confidence interval [CI], 7.0%-8.1%). Men were more likely to have an eye injury than women (odds ratio [OR], 2.1 [95% CI, 1.8-2.5]). After adjusting for gender and other demographic factors, ocular trauma was significantly more frequent among laborers (OR, 1.5 [95% CI, 1.2-1.7]) when compared with other occupational groups. After adjusting for gender, injury with vegetable matter such as a thorn, branch of a tree, plant secretion, etc. (n = 373 [45.3%]) was the major cause of trauma reported in this population. The majority of the eye injuries occurred at the workplace (n = 461 [55.9%]), followed by home (n = 179 [21.7%]). The majority of those affected (n = 806 [97.8%]) did not wear any eye protection at the time of trauma. A significant proportion (n = 307 [43.1%]) of subjects who sought treatment for an eye injury went to an ophthalmologist. Trauma was responsible for unilateral blindness in 39 subjects, an age- and gender-adjusted prevalence of 0.6% (95% CI, 0.4%-0.8%). CONCLUSIONS: Most ocular injuries in this rural population occurred at the workplace, suggesting the need to explore workplace strategies to minimize ocular trauma as a priority. Eye care programs targeting high-risk ocular trauma groups may need to consider ocular trauma as a priority in eye health awareness strategies to reduce blindness due to trauma.

Awareness of glaucoma in the rural population of Southern India.

PURPOSE: To explore the awareness of glaucoma amongst the rural population of Andhra Pradesh, India. MATERIALS AND METHODS: A total of 7775 subjects of all ages, representative of the rural population of Andhra Pradesh, participated in the Andhra Pradesh Eye Disease Study. The responses of subjects older than 15 years (n=5573) who completed a structured questionnaire regarding awareness (heard of glaucoma) and knowledge (understanding of disease) of glaucoma formed the basis of this study. RESULTS: Awareness of glaucoma (n=18; 0.32%) was very poor in this rural population, and females were significantly less aware (p=0.007). Awareness of glaucoma was also significantly less among illiterate persons (p<0.0001), and socially backward population (p<0.0001). Majority of the respondents who were aware of glaucoma (n=10; 55.6%) did not know if visual loss due to glaucoma was permanent or reversible. The major source of awareness of glaucoma in this population was TV/magazines and other media followed by information from a relative or acquaintance suffering from the disease. CONCLUSION: Awareness of glaucoma is very poor in the rural areas of southern India. The data suggest the need for community-based health education programmes to increase the level of awareness and knowledge about glaucoma.

Outcome and number of cataract surgeries in India: policy issues for blindness control.

PURPOSE: To assess what impact attention to quality of cataract surgery and postoperative follow up can have on cataract blindness in India, and to estimate the number of surgeries needed to eliminate cataract blindness in India. METHODS: In a population-based sample of 5268 persons in two rural areas in the state of Andhra Pradesh, India, data on the visual outcome of cataract surgery were obtained on 129 eyes of 106 persons operated previously. These were compared with the visual outcome of cataract surgery performed during 1999 in 2394 eyes of 2213 persons at two new rural eye centres set up in these areas that pay particular attention to the quality of eye care. Blindness in an eye was defined as presenting distance visual acuity less than 6/60, and in a person as this acuity level in the better eye. These data were extrapolated to India. RESULTS: In the population-based sample, of the 129 operated eyes, 51 (39.5%) were blind after surgery, which included 41 (31.8%) from cataract surgery-related causes. Of the 106 persons in the population sample who had had cataract surgery in one or both eyes, 26 (24.5%) were still blind. In contrast, for the cataract surgery at the two rural eye centres paying attention to quality, 3.1% of the eyes and 1.8% of the persons were blind soon after surgery, but these figures could increase 2.6 times over the lifetime of these persons. The 3.5 million cataract surgeries in India in 2000 are estimated to result in 0.32 million persons having blindness averted over their lifetime. To eliminate cataract blindness in India, an estimated 9 million good-quality cataract surgeries are needed every year during 2001-2005, increasing to over 14 million surgeries needed every year during 2016-2020 on persons most likely to go blind from cataract. CONCLUSIONS: The number of persons in whom blindness is being averted due to cataract surgery in India is currently a very small fraction of the number blind from cataract. If adequate attention is given to the quality of eye care, for the current number of cataract surgeries in India it should be possible to increase by threefold the number in whom blindness can be averted with cataract surgery. In addition to improving quality, the annual number of cataract surgeries has to be at least threefold the current number during 2006-2010 if cataract blindness in India is to be eliminated.

Planning low vision services in India : a population-based perspective.

OBJECTIVE: To assess the prevalence and causes of low vision in a population in southern India for planning low vision services. DESIGN: Population-based, cross-sectional study. PARTICIPANTS: A total of 10,293 persons of all ages from 94 clusters representative of the population of the Indian state of Andhra Pradesh. METHODS: The participants underwent a detailed eye examination, including measurement of visual acuity with logarithm of the minimum angle of resolution charts, refraction, slit-lamp biomicroscopy, applanation tonometry, gonioscopy, and stereoscopic dilated fundus evaluation. Automated threshold visual fields and slit-lamp and fundus photography were done when indicated using predefined criteria. MAIN OUTCOME MEASURES: Low vision was defined as permanent visual impairment that was not correctable with refractive error correction or surgical intervention. The participants with best-corrected distance visual acuity <6/18 to perception of light or central visual field <10 degrees because of an untreatable cause in both eyes were considered as having low vision. RESULTS: Low vision was present in 144 participants, an age, gender, and urban-rural distribution adjusted prevalence of 1.05% (95% confidence interval, 0.82%-1.28%). The most frequent causes of low vision included retinal diseases (35.2%), amblyopia (25.7%), optic atrophy (14.3%), glaucoma (11.4%), and corneal diseases (8.6%). Multivariate analysis showed that the prevalence of low vision was significantly higher with increasing age, and there was a trend for higher prevalence with decreasing socioeconomic status. Extrapolating these data to the estimated 1014 million population of India in the year 2000, 10.6 (95% confidence interval, 8.4-12.8) million people would have low vision. CONCLUSIONS: These data imply that there is a significant burden of low vision in this population, suggesting the need for low vision services.

Population-based study of spectacles use in southern India.

This study assessed the use of spectacles and its demographic associations in a sample representative of the population of the Indian state of Andhra Pradesh. A total of 11,786 subjects of all ages were sampled from 94 clusters in one urban and three rural study areas of Andhra Pradesh using stratified, random, cluster, systematic sampling. The eligible subjects underwent detailed interview and eye examination including dilated examination of the posterior segment. The data on the use of spectacles were analysed for subjects > 15 years of age. A total of 7,432 subjects > 15 years of age participated in the study of whom 1,030 (13.8%) had a refractive error of spherical equivalent +/- 3.00 Diopter or worse. The prevalence of current use of spectacles in those with spherical equivalent +/- 3.00 Diopter or worse, who were likely to be visually impaired without refractive correction, was 34.2% (95% confidence interval 30.3-38%) and of previous use of spectacles was 12.3% (95% confidence interval 10.3-14.3%). The odds of using spectacles currently were significantly higher for those with any level of education, those living in the urban area, and for those with aphakia or psuedophakia as compared with natural refractive error. Among those who had used spectacles previously, 43.8% had discontinued because they felt that either the prescription was incorrect or that the spectacles were uncomfortable, suggesting poor quality of refractive services, and another 19.6% had lost the pair and could not afford to buy another pair. These data suggest that the use of spectacles in this population by those with refractive error was not optimal. Two-thirds of those with spherical equivalent +/- 3.00 Diopter or worse were not using spectacles. Of those who had discontinued the use of spectacles, a significant proportion did so for reasons related to poor quality of refractive services. Strategies such as vision screening programmes and eye health promotion need to be implemented, the quality of refractive services monitored and the cost of spectacles regulated, if the substantial burden of visual impairment due to refractive error in this population is to be reduced.

Population-based assessment of refractive error in India: the Andhra Pradesh eye disease study.

PURPOSE: To assess the prevalence, distribution, and demographic associations of refractive error in the population of the southern Indian state of Andhra Pradesh. METHODS: From 94 clusters in one urban and three rural areas of Andhra Pradesh, 11 786 persons of all ages were sampled using a stratified, random, cluster, systematic sampling strategy in the Andhra Pradesh Eye Disease Study, a population-based cross-sectional study. A total of 10 293 people underwent an interview and detailed dilated eye examination. Refraction was performed by ophthalmic personnel trained in the study procedures. Objective refraction under cycloplegia was assessed for participants < or = 15 years of age and subjective refraction for those > 15 years of age. Myopia was defined as spherical equivalent worse than -0.50 D and hyperopia as spherical equivalent worse than +0.50 D. RESULTS: In the participants < or = 15 years of age, the prevalence of myopia was 3.19% (95% confidence interval [CI] 2.24-4.13%) and of hyperopia was 62.62% (95% CI 57.10-68.13%). In this age group, myopia increased with increasing age and was more prevalent in the urban study area, and hyperopia prevalence was greater in the participants < 10 years of age. In participants > 15 years of age, the prevalence of myopia was 19.45% (95% CI 17.88-21.02%) and of hyperopia was 8.38% (95% CI 6.91-9.85%). Myopia and hyperopia increased with increasing age. Myopia was more common in males, those with education higher than class 12, those with nuclear cataract, and those living in rural study areas. Hyperopia was more common in females, those with any level of formal education, and those living in the urban area and in the well-off rural study area. CONCLUSIONS: There is significant refractive error in this population. These data on the distribution and associations of refractive error can be useful for the planning of refractive eye-care services.

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.