Causes of low vision and blindness in rural Indonesia

AIM: To determine the prevalence rates and major contributing causes of low vision and blindness in adults in a rural setting in Indonesia METHODS: A population based prevalence survey of adults 21 years or older (n=989) was conducted in five rural villages and one provincial town in Sumatra, Indonesia. One stage household cluster sampling procedure was employed where 100 households were randomly selected from each village or town. Bilateral low vision was defined as habitual VA (measured using tumbling "E" logMAR charts) in the better eye worse than 6/18 and 3/60 or better, based on the WHO criteria. Bilateral blindness was defined as habitual VA worse than 3/60 in the better eye. The anterior segment and lens of subjects with low vision or blindness (both unilateral and bilateral) (n=66) were examined using a portable slit lamp and fundus examination was performed using indirect ophthalmoscopy. RESULTS: The overall age adjusted (adjusted to the 1990 Indonesia census population) prevalence rate of bilateral low vision was 5.8% (95% confidence interval (CI) 4.2 to 7.4) and bilateral blindness was 2.2% (95% CI 1.1 to 3.2). The rates of low vision and blindness increased with age. The major contributing causes for bilateral low vision were cataract (61.3%), uncorrected refractive error (12.9%), and amblyopia (12.9%), and the major cause of bilateral blindness was cataract (62.5%). The major causes of unilateral low vision were cataract (48.0%) and uncorrected refractive error (12.0%), and major causes of unilateral blindness were amblyopia (50.0%) and trauma (50.0%). CONCLUSIONS: The rates of habitual low vision and blindness in provincial Sumatra, Indonesia, are similar to other developing rural countries in Asia. Blindness is largely preventable, as the major contributing causes (cataract and uncorrected refractive error) are amenable to treatment.     

Prevalence of blindness and low vision in Malaysian population: results from the National Eye Survey 1996

BACKGROUND: A national eye survey was conducted in 1996 to determine the prevalence of blindness and low vision and their major causes among the Malaysian population of all ages. METHODS: A stratified two stage cluster sampling design was used to randomly select primary and secondary sampling units. Interviews, visual acuity tests, and eye examinations on all individuals in the sampled households were performed. Estimates were weighted by factors adjusting for selection probability, non-response, and sampling coverage. RESULTS: The overall response rate was 69% (that is, living quarters response rate was 72.8% and household response rate was 95.1%). The age adjusted prevalence of bilateral blindness and low vision was 0.29% (95% CI 0.19 to 0.39%), and 2.44% (95% CI 2.18 to 2.69%) respectively. Females had a higher age adjusted prevalence of low vision compared to males. There was no significant difference in the prevalence of bilateral low vision and blindness among the four ethnic groups, and urban and rural residents. Cataract was the leading cause of blindness (39%) followed by retinal diseases (24%). Uncorrected refractive errors (48%) and cataract (36%) were the major causes of low vision. CONCLUSION: Malaysia has blindness and visual impairment rates that are comparable with other countries in the South East Asia region. However, cataract and uncorrected refractive errors, though readily treatable, are still the leading causes of blindness, suggesting the need for an evaluation on accessibility and availability of eye care services and barriers to eye care utilisation in the country.     

Prevalence and causes of blindness and low vision among adults in Fiji

Background: To estimate the prevalence and causes of blindness and low vision among adults aged ≥40 years in Fiji. Design: Population‐based cross‐sectional study. Participants: Adults aged ≥40 years in Viti Levu, Fiji. Method: A population‐based cross‐sectional survey used multistage cluster random sampling to identify 34 clusters of 40 people. A cause of vision loss was determined for each eye with presenting vision worse than 6/18. Main Outcome Measures: Blindness (better eye presenting vision worse than 6/60), low vision (better eye presenting vision worse than 6/18, but 6/60 or better). Results: Of 1892 people enumerated, 1381 participated (73.0%). Adjusting sample data for ethnicity, gender, age and domicile, the prevalence of blindness was 2.6% (95% confidence interval 1.7, 3.4) and low vision was 7.2% (95% confidence interval 5.9, 8.6) among adults aged ≥40 years. On multivariate analysis, being ≥70 years was a risk factor for blindness, but ethnicity, gender and urban/rural domicile were not. Being Indo‐Fijian, female and older were risk factors for vision impairment (better eye presenting vision worse than 6/18). Cataract was the most common cause of bilateral blindness (71.1%). Among participants with low vision, uncorrected refractive error caused 63.3% and cataract was responsible for 25.0%. Conclusion: Strategies that provide accessible cataract and refractive error services producing good quality outcomes will likely have the greatest impact on reducing vision impairment.     

Blindness and Eye Disease in Cambodia

Purpose: To assess the prevalence and etiology of blindness and low vision and to assess the prevalence of common eye diseases in central Cambodia. Methods: In this cross-sectional, population-based study, 6,558 residents of Kandal Province, Cambodia were registered, and 5,803 (88.5%) were interviewed and examined. This house-to-house survey was conducted by a team consisting of a senior ophthalmologist, a Cambodian eye doctor, and eight Cambodian eyecare workers. Results: The prevalence of bilateral blindness (visual acuity <3/60) is 1.1% (95% confidence interval [CI], 0.9–1.4), and an additional 4.4% (95% CI, 3.9–5.0) have low vision (visual acuity < 6/18, ≥3/60 in the better eye). The major causes of bilateral blindness are cataract (67.4%), phthisis (6.1%), uncorrected refractive error (6.1%), corneal scar (5.3%), uncorrected aphakia (3.0%), trachoma corneal scar (3.0%), optic atrophy (3.0%), and others (6.1%). The major causes of low vision are uncorrected refractive error (49.8%) and cataract (42.7%). The prevalence of unilateral blindness is 1.2% (95% CI, 0.9–1.4), often caused by cataract, corneal scar, or phthisis. Trauma due to landmine explosions and war-related injuries was frequently the underlying etiology in subjects with phthisis, corneal scarring, or other pathology.Conclusions: The prevalence of blindness and low vision in Cambodia is relatively high compared to other developing countries. Most of the causes of blindness and low vision are treatable or preventable. Landmines and other war-related injuries are an important cause of ocular injury. These results will assist in developing a national plan for the prevention of blindness in Cambodia.     

Blindness and low vision in Cape Verde Islands: results of a national eye survey

AIMS: Prior to establishing a national prevention of blindness program a population based survey was conducted in Cape Verde Islands in1998. The objectives of the survey were to estimate the overall and age-specific prevalence of blindness and low vision, to identify the main disorders causing blindness and low vision, and to estimate the population need for basic eye care services. METHODS: A two-level cluster random sampling procedure was used, selecting 30 clusters from the nine inhabited islands and 3,803 persons of all ages were included in the sample. RESULTS: 3,374 persons were examined (coverage 88.7%). The prevalence of bilateral blindness (visual acuity in the better eye less than 3/60) was 0.8% (95% confidence interval [CI] 0.5-1.1), of bilateral low vision (6/18 to 3/60 in the better eye) 1.7% (95% CI: 1.3-2.2) and of monocular blindness 1.5% (95% CI: 1.2-2.0). The major causes of blindness were age related cataract and glaucoma (57.7% and 15.4%, respectively, of blind people recruited). The major causes of bilateral low vision were cataract, refractive errors, and macular disorders (46.2%, 26.8%, and 8.9%, respectively, of persons with low vision). Nontrachomatous corneal opacities accounted for 7.7% of bilateral and for 11.5% of monocular blindness. Vascular retinopathy was responsible for 7.7% of bilateral and for 9.6% of monocular blindness. Trachoma is not a public health problem as only 2.3% of children less than 10 years of age were suffering from active trachoma. Palpebral or limbal vernal conjunctivitis were encountered in 4.5% of persons under 25. CONCLUSION: More than half of the visual impairments are treatable by provision of cataract surgery and cataract has been indicated as a priority target in the recently designed National Blindness Program of the Cape Verde Republic. Pathologic conditions such as diabetes are emerging as serious burden for ageing populations and account for most of the retinal vascular disease.     

Blindness and eye disease in Cambodia

PURPOSE: To assess the prevalence and etiology of blindness and low vision and to assess the prevalence of common eye diseases in central Cambodia. METHODS: In this cross-sectional, population-based study, 6,558 residents of Kandal Province, Cambodia were registered, and 5,803 (88.5%) were interviewed and examined. This house-to-house survey was conducted by a team consisting of a senior ophthalmologist, a Cambodian eye doctor, and eight Cambodian eyecare workers. RESULTS: The prevalence of bilateral blindness (visual acuity <3/60) is 1.1% (95% confidence interval [CI], 0.9-1.4), and an additional 4.4% (95% CI, 3.9-5.0) have low vision (visual acuity < 6/18, > or =3/60 in the better eye). The major causes of bilateral blindness are cataract (67.4%), phthisis (6.1%), uncorrected refractive error (6.1%), corneal scar (5.3%), uncorrected aphakia (3.0%), trachoma corneal scar (3.0%), optic atrophy (3.0%), and others (6.1%). The major causes of low vision are uncorrected refractive error (49.8%) and cataract (42.7%). The prevalence of unilateral blindness is 1.2% (95% CI, 0.9-1.4), often caused by cataract, corneal scar, or phthisis. Trauma due to landmine explosions and war-related injuries was frequently the underlying etiology in subjects with phthisis, corneal scarring, or other pathology.CONCLUSIONS: The prevalence of blindness and low vision in Cambodia is relatively high compared to other developing countries. Most of the causes of blindness and low vision are treatable or preventable. Landmines and other war-related injuries are an important cause of ocular injury. These results will assist in developing a national plan for the prevention of blindness in Cambodia.     

Blindness and Low Vision in Cape Verde Islands: Results of a National Eye Survey

Aims: Prior to establishing a national prevention of blindness program a population based survey was conducted in Cape Verde Islands in1998. The objectives of the survey were to estimate the overall and age-specific prevalence of blindness and low vision, to identify the main disorders causing blindness and low vision, and to estimate the population need for basic eye care services. Methods: A two-level cluster random sampling procedure was used, selecting 30 clusters from the nine inhabited islands and 3,803 persons of all ages were included in the sample. Results: 3,374 persons were examined (coverage 88.7%). The prevalence of bilateral blindness (visual acuity in the better eye less than 3/60) was 0.8% (95% confidence interval [CI] 0.5–1.1), of bilateral low vision (6/18 to 3/60 in the better eye) 1.7% (95% CI: 1.3–2.2) and of monocular blindness 1.5% (95% CI: 1.2–2.0). The major causes of blindness were age related cataract and glaucoma (57.7% and 15.4%, respectively, of blind people recruited). The major causes of bilateral low vision were cataract, refractive errors, and macular disorders (46.2%, 26.8%, and 8.9%, respectively, of persons with low vision). Nontrachomatous corneal opacities accounted for 7.7% of bilateral and for 11.5% of monocular blindness. Vascular retinopathy was responsible for 7.7% of bilateral and for 9.6% of monocular blindness. Trachoma is not a public health problem as only 2.3% of children less than 10 years of age were suffering from active trachoma. Palpebral or limbal vernal conjunctivitis were encountered in 4.5% of persons under 25. Conclusion: More than half of the visual impairments are treatable by provision of cataract surgery and cataract has been indicated as a priority target in the recently designed National Blindness Program of the Cape Verde Republic. Pathologic conditions such as diabetes are emerging as serious burden for ageing populations and account for most of the retinal vascular disease.     

Causes of blindness, low vision, and questionnaire-assessed poor visual function in Singaporean Chinese adults: The Tanjong Pagar Survey

OBJECTIVE: To determine the prevalence rates and causes of low vision, blindness, and patient-assessed deficient visual function among Singaporean Chinese adults. DESIGN: Population-based cross-sectional survey. PARTICIPANTS: Singaporean Chinese adults 40 to 79 years old (n = 1152). METHODS: From an initial sampling frame of 40- to 79-year-old Chinese in the Tanjong Pagar district in Singapore, 2000 subjects were selected using a disproportionate, stratified, clustered, random-sampling method. Of 1717 eligible subjects, 1232 were examined (participation rate = 71.8%), and 80 adults who did not have visual acuity (VA) data were excluded from the analysis. MAIN OUTCOME MEASURES: Bilateral low vision was defined as best-corrected VA (BCVA) worse than 6/18 and 3/60 or better, and bilateral blindness as BCVA worse than 3/60 in the better eye or constriction of the visual field to within 10 degrees of fixation, in accordance with the World Health Organization criteria. Patient-assessed visual function was measured using a modified VF-14 questionnaire. RESULTS: The age- and gender-adjusted prevalence rates were 1.1% (95% confidence interval [CI], 0.6-1.8) for bilateral low vision and 0.5% (95% CI, 0.2-1.1) for bilateral blindness, and the mean visual function score was 98.6. The rates of bilateral low vision and blindness increased with age, whereas visual function scores decreased with age, even after adjusting for gender and education. Cataract accounted for 58.8% of bilateral low vision, 20.0% of bilateral blindness, and 52.0% of poor visual function (score<90). Glaucoma contributed to 60.0% of bilateral blindness. CONCLUSION: The age- and gender-adjusted rates of low vision and blindness were 1.1% and 0.5%, respectively. Glaucoma is a leading cause of blindness in Singaporean Chinese adults, in addition to well-recognized causes in the rest of Asia such as cataract.     

Prevalence and causes of blindness and low vision in Timor-Leste

AIM: To estimate the prevalence and causes of blindness and low vision in people aged > or = 40 years in Timor-Leste. METHOD: A population-based cross-sectional survey using multistage cluster random sampling to identify 50 clusters of 30 people. A cause of vision loss was determined for each eye presenting with visual acuity worse than 6/18. RESULTS: Of 1470 people enumerated, 1414 (96.2%) were examined. The age, gender and domicile-adjusted prevalence of functional blindness (presenting vision worse than 6/60 in the better eye) was 7.4% (95% CI 6.1 to 8.8), and for blindness at 3/60 was 4.1% (95% CI 3.1 to 5.1). The adjusted prevalence for low vision (better eye presenting vision of 6/60 or better, but worse than 6/18) was 17.7% (95% CI 15.7 to 19.7). Gender was not a risk factor for blindness or low vision, but increasing age, illiteracy, subsistence farming, unemployment and rural domicile were risk factors for both. Cataract was the commonest cause of blindness (72.9%) and an important cause of low vision (17.8%). Uncorrected refractive error caused 81.3% of low vision. CONCLUSION: Strategies that make good-quality cataract and refractive error services available, affordable and accessible, especially in rural areas, will have the greatest impact on vision impairment.     

Cause-specific prevalence of bilateral visual impairment in Victoria, Australia: the Visual Impairment Project

PURPOSE: To study the cause-specific prevalence of eye diseases causing bilateral visual impairment in Australian adults. DESIGN: Two-site, population-based cross-sectional study. PARTICIPANTS: Participants were aged 40 years and older and resident in their homes at the time of recruitment for the study. The study was conducted during 1992 through 1996. METHODS: The study uses a cluster stratified random sample of 4744 participants from two cohorts, urban, and rural Victoria. Participants completed a standardized interview and eye examination, including presenting and best-corrected visual acuity, visual fields, and dilated ocular examination. The major cause of vision loss was identified for all participants found to be visually impaired. Population-based prevalence estimates are weighted to reflect the age and gender distribution of the two cohorts in Victoria. MAIN OUTCOME MEASURES: Visual impairment was defined by four levels of severity on the basis of best-corrected visual acuity or visual field: <6/18 > or =6/60 and/or <20 degrees > or =10 degrees radius field, moderate vision impairment; severe vision impairment, <6/60 > or =3/60 and/or <10 degrees > or =5 degrees radius field; and profound vision impairment <3/60 and/or <5 degrees radius field. In addition, less-than-legal driving vision, <6/12 > or =6/18, and/or homonymous hemianopia were defined as mild vision impairment. In Australia, legal blindness includes severe and profound vision impairment. RESULTS: The population-weighted prevalence of diseases causing less-than-legal driving or worse impairment in the better eye was 42.48/1000 (95% confidence interval [CI], 30.11, 54.86). Uncorrected refractive error was the most frequent cause of bilateral vision impairment, 24.68/1000 (95% CI, 16.12, 33.25), followed by age-related macular degeneration (AMD), 3.86/1000 (95% CI, 2.17, 5.55); other retinal diseases, 2.91/1000 (95% CI, 0.74, 5.08); other disorders, 2.80/1000 (95% CI, 1.17, 4.43); cataract, 2.57/1000 (95% CI, 1.38, 3.76); glaucoma, 2.32/1000 (95% CI, 0.72, 3.92); neuro-ophthalmic disorders, 1.80/1000 (95% CI, 0, 4.11); and diabetic retinopathy, 1.53/1000 (95% CI, 0.71, 2.36). The prevalence of legal blindness was 5.30/1000 (95% CI, 3.24, 7.36). Although not significantly different, the causes of legal blindness were uncorrected refractive errors, AMD, glaucoma, other retinal conditions, and other diseases. CONCLUSIONS: Significant reduction of visual impairment may be attained with the application of current knowledge in refractive errors, diabetes mellitus, cataract, and glaucoma. Although easily preventable, uncorrected refractive error remains a major cause of vision impairment.     

Ocular problems of young adults in rural Nigeria

Objectives: To determine the common eye diseases as well as the prevalence and causes of blindness and visual impairment in young adult residents of rural areas of Anambra State, Nigeria. Materials and methods: Three rural villages in Anambra State, Nigeria were selected by simple random sampling. A structured questionnaire on demographic characteristics, symptoms and attitude to eye diseases was administered to residents aged 18–49 years. Ocular examination included visual acuity estimation, colour vision test, tonometry, refraction and ophthalmoscopy. Skin-snip was examined for microfilaria. Results: The common ocular problems in the 510 young adults examined were presbyopia (33.3%), refractive errors (41.1%), allergic conjunctivitis (8.2%), pterygium (8.2%), pingueculum (5.9%) and colour vision defect (2.4%). Bilateral blindness occurredin 1.2%, uniocular blindness in 0.8% and 1.7% had visual impairment in their better eyes. Glaucoma and sequelae of congenital cataract caused bilateral blindness while visual impairment was due to refractive errors, cataract, corneal opacities and uveitis. Trauma predisposed to uniocular blindness and visual impairment. Conclusions: Eyeglasses alone would alleviate visual impairment and ensure good near vision in more than 47% of the subjects. The prevalence of blindness could be reduced through early detection of glaucoma, congenital cataract and ocular trauma. This revised version was published online in July 2006 with corrections to the Cover Date.     

Prevalence and Causes of Blindness and Low Vision Revisited after 5 years of Eye Care in Timor-Leste

Purpose: To estimate the 2010 prevalence and causes of blindness and low vision among Timor-Leste adults aged ≥40 years, and compare these to the results of a survey conducted 5 years previously.

Method: A population-based cross-sectional survey used multistage cluster random sampling proportionate to size to identify 50 clusters of 45 people each. Cause of vision loss was determined for each eye with presenting visual acuity worse than 6/18.

Results: A participation rate of 89.5% (n?=?2014) was achieved. The gender-age-domicile adjusted prevalence was 7.7% (95% confidence interval [CI] 6.5, 8.8) for 6/60, and 3.6% (95% CI 2.7, 4.4) for 3/60 blindness (better eye presenting vision worse than 6/60 and 3/60, respectively) among Timorese aged ≥40 years. Cataract caused most blindness (69.3% at 6/60). The population prevalence of low vision (better eye presenting vision of 6/60 or better, but worse than 6/18) was 13.6% (95%CI 12.1, 15.1), most caused by uncorrected refractive error (57.4%) or cataract (39.5%). The prevalence and causes of blindness were unchanged compared with 5 years earlier, but low vision was less common.

Conclusion: Unusually for a developing country, Timor-Leste has initiated a cycle of evidence-based eye care in which, although with limitations, population data are periodically available for monitoring and planning.     

Prevalence of Blindness and Low Vision in a Rural Population in Northern China: Preliminary Results from a Population-Based Survey

Purpose: To investigate the prevalence of visual impairment in a rural northern Chinese population.

Methods: A cross-sectional, population-based survey was conducted in 2010 in Ci County, Hebei Province in northern China. Residents aged 7 years and older in Lucunying Town, located within Ci County, underwent presenting visual acuity (VA) testing at home; those with presenting VA <20/60 were invited to participate in further examination at the local hospital. Population-weighted prevalences of blindness and low vision were determined according to World Health Organization definitions.

Results: Among the 24,539 residents aged older than 7 years, 20,298 (82.7%) participated in the study, and 20,072 (98.9%) of these had valid VA data. The population-weighted prevalence rates of presenting bilateral blindness and bilateral low vision were 0.3% and 2.4% for the entire population, 0% and 0.5% for residents 7–39 years of age, and 0.8% and 6.4% for residents 40 years and older, respectively. Based on best-corrected VA, the corresponding prevalence rates of bilateral blindness and bilateral low vision were 0.2% and 1.4% for the entire population, 0% and 0.1% for residents 7–39 years, and 0.6% and 4.0% for residents 40 years and older, respectively. Prevalence rates of blindness and low vision were generally higher among women than men. Blindness and low vision increased with age among residents 40 years and older.

Conclusion: Our findings highlight the need for eye healthcare services for visual impairment in rural China.     

A population-based eye survey of older adults in a rural district of Rajasthan: I. Central vision impairment, blindness, and cataract surgery

PURPOSE: To assess the prevalence of central vision blindness and cataract surgery in older adults in rural northwest India. DESIGN: Population-based, cross-sectional study. PARTICIPANTS: A total of 4284 examined persons 50 years of age or older. METHODS: A random selection of village-based clusters was used to identify a population sample in the predominantly rural Bharatpur district of Rajasthan. Eligible subjects in the 25 selected clusters were enumerated through a door-to-door household survey and invited to village sites for visual acuity testing and eye examination early in 1999. The principal cause of reduced central vision was identified for eyes that had visual acuity worse than 6/18. Independent replicate testing for quality assurance monitoring took place in participants with reduced vision and in a sample of those with normal vision in five of the study clusters. MAIN OUTCOME MEASURES: Presenting and best-corrected visual acuity and lens status. RESULTS: A total of 4728 eligible persons in 2821 households were enumerated, and 4284 (90.6%) were examined. The prevalence of presenting and best-corrected visual acuity worse than 6/60 in both eyes was 11.9% (95% confidence interval: 10.0%-13.9%) and 6.1% (95% CI: 4.7%-7.4%), respectively. Presenting blindness was associated with increasing age, female gender, lack of schooling, and rural residence. Cataract was the principal cause of blindness in one or both eyes in 67.5% of blind persons, with uncorrected aphakia and other refractive error affecting 18.4% in at least one eye. The prevalence of cataract surgery was 12.8% (95% CI: 11.6%-14.0%), with an estimated 65.7% of the cataract blind operated on; low surgical coverage was associated with lack of schooling. CONCLUSIONS: Blindness, particularly blindness because of cataract, continues to be a significant problem among the elderly living in remote areas of rural northwest India. Increased attention should be given to reaching women and the illiterate.     

Prevalence and causes of low vision and blindness in an urban population: The Chennai Glaucoma Study

Aim:

To evaluate the prevalence and causes of low vision and blindness in an urban south Indian population.

Settings and Design:

Population-based cross-sectional study. Exactly 3850 subjects aged 40 years and above from Chennai city were examined at a dedicated facility in the base hospital.

Materials and Methods:

All subjects had a complete ophthalmic examination that included best-corrected visual acuity. Low vision and blindness were defined using World Health Organization (WHO) criteria. The influence of age, gender, literacy, and occupation was assessed using multiple logistic regression.

Statistical Analysis:

Chi-square test, t-test, and multivariate analysis were used.

Results:

Of the 4800 enumerated subjects, 3850 subjects (1710 males, 2140 females) were examined (response rate, 80.2%). The prevalence of blindness was 0.85% (95% CI 0.6–1.1%) and was positively associated with age and illiteracy. Cataract was the leading cause (57.6%) and glaucoma was the second cause (16.7%) for blindness. The prevalence of low vision was 2.9% (95% CI 2.4–3.4%) and visual impairment (blindness + low vision) was 3.8% (95% CI 3.2–4.4%). The primary causes for low vision were refractive errors (68%) and cataract (22%).

Conclusions:

In this urban population based study, cataract was the leading cause for blindness and refractive error was the main reason for low vision.     

Prevalence and causes of visual impairment in elderly Amis aborigines in eastern Taiwan (the Amis Eye Study)

Purpose

To investigate the prevalence and causes of visual impairment in elderly Amis aborigines in Eastern Taiwan.

Methods

Population-based cross-sectional study of visual impairment of elderly Amis (65?years of age or older). We conducted ocular examinations on 2,316 participants, which represent 61.2?% of the elderly population. We used WHO criteria to identify visual impaired subjects, and the causes were analyzed.

Results

Ninety-four subjects were identified with low vision and nineteen were blind. The prevalence of low vision was 4.06?% (95?% confidence interval, 3.26, 4.56?%); that of blindness was 0.82?% (95?% confidence interval, 0.45, 1.19?%). Cataracts (47.79?%) were the main cause of visual impairment, followed by age-related macular degeneration (15.93?%), corneal opacity (7.96?%), optic neuropathy (7.96?%), diabetic retinopathy (5.31?%), and retinitis pigmentosa (2.65?%). Glaucoma was a minor cause of visual impairment. There were no significant gender differences in the prevalence and specific causes of visual impairment.

Conclusion

The prevalence of treatable causes of vision impairment, for example cataracts and corneal opacity, is high among the elderly Amis aborigines. They would, therefore, benefit from a more aggressive and in-depth eye-care program as a blindness-prevention strategy.     

Visual impairment in the 40- to 64-year-old population of Shahroud, Iran

Purpose

To determine the prevalence of visual impairment by age and gender in Shahroud.

Methods

Using random cluster sampling, 6311 Shahroud inhabitants who were between 40 and 64 years old were invited for ophthalmological examinations. Visual acuity worse than 0.5 LogMAR (20/60) and 1.3 LogMAR (20/400) in the better eye was regarded as low vision and blindness, respectively. The cause of blindness was determined by an ophthalmologist and in a person with more than one cause, the most correctable cause was regarded as the main cause.

Results

This study was conducted on 5190 participants (response rate: 82.2%). On the basis of presenting visual acuity, the prevalence of low vision and blindness was found to be 1.8% (95% confidence interval (CI): 1.4–2.10) and 0.5% (95% CI: 0.3–0.7), respectively. Based on corrected vision, these values were 0.5% (95% CI: 0.3–0.7) and 0.3% (95% CI: 0.1–0.4), respectively. Visual impairment increased with age in women (P<0.001). Uncorrected refractive errors (63.9%), cataract (20.2%), and amblyopia (5.9%) were the most common causes of visual impairment based on presenting vision. Based on corrected vision, however, cataract (42.5%), amblyopia (12.5%), and retinitis pigmentosa (7.5%) were the most common causes of visual impairment.

Conclusion

Although the prevalence of visual impairment in the city of Shahroud was determined to be lower than two previous studies in the country, correction of refractive errors and cataract could minimize the rate of visual impairment in this population as they were shown to comprise 85% of the causes of visual impairment. The elderly women need to receive more attention.     

Prevalence of blindness and low vision in a rural population in northern china: preliminary results from a population-based survey

Purpose: To investigate the prevalence of visual impairment in a rural northern Chinese population. Methods: A cross-sectional, population-based survey was conducted in 2010 in Ci County, Hebei Province in northern China. Residents aged 7 years and older in Lucunying Town, located within Ci County, underwent presenting visual acuity (VA) testing at home; those with presenting VA <20/60 were invited to participate in further examination at the local hospital. Population-weighted prevalences of blindness and low vision were determined according to World Health Organization definitions. Results: Among the 24,539 residents aged older than 7 years, 20,298 (82.7%) participated in the study, and 20,072 (98.9%) of these had valid VA data. The population-weighted prevalence rates of presenting bilateral blindness and bilateral low vision were 0.3% and 2.4% for the entire population, 0% and 0.5% for residents 7-39 years of age, and 0.8% and 6.4% for residents 40 years and older, respectively. Based on best-corrected VA, the corresponding prevalence rates of bilateral blindness and bilateral low vision were 0.2% and 1.4% for the entire population, 0% and 0.1% for residents 7-39 years, and 0.6% and 4.0% for residents 40 years and older, respectively. Prevalence rates of blindness and low vision were generally higher among women than men. Blindness and low vision increased with age among residents 40 years and older. Conclusion: Our findings highlight the need for eye healthcare services for visual impairment in rural China.     

天津郊县盲及低视力眼病调查分析

目的:调查低视力门诊盲及低视力眼病患病情况,获得流行病学资料。方法:2006-08/2007-07对来我院低视力门诊普查的天津郊县6209例行眼科检查并进行检查结果统计分析。结果:全部对象中盲及低视力患者326例(5.25%),其中白内障98例(1.58%),青光眼82例(1.32%),角膜病42例(0.68%),视神经萎缩31例(0.50%),糖尿病视网膜病变14例(0.23%),弱视10例(0.16%),原发性视网膜脱离8例(0.13%),老年性黄斑变性6例(0.10%),其它(包括:眼部炎症、外伤、视网膜中央静脉阻塞、视网膜色素变性)35例(0.56%)。结论:低视力和盲的门诊患病率随年龄增长而增高,白内障和青光眼是致盲的主要原因。现阶段白内障手术仍为防盲治盲工作重点,同时应加强卫生宣传及基层眼病普查制度。     

社区中老年人群致盲与低视力眼病调查

目的 了解社区中老年人群盲与低视力的情况.方法 根据北京市西长安街社区居委会人口登记,采用逐户上门登记的方法确认被调查者的资格.对待检者2 833人应用问卷调查法询问被调查者的一般状况和生活习惯.对目标受检者进行裸眼视力、小孔视力、非接触眼压测量、裂隙灯检查、检眼镜检查、自动验光仪验光等.采用WHO推荐标准对受检人群盲及低视力结果进行评估,对目标受检人群致盲和低视力的原因进行分析.结果 登记50岁以上人口数2 833人,实际调查人数为2 410人,受检率为85.07%.该社区50岁及以上人群盲的患病率为0.79 %,低视力的患病率为5.64%.导致盲的首要病因是白内障,其次是青光眼和视网膜病变.导致低视力的首要病因是白内障,其次是屈光不正和糖尿病视网膜病变(DR).结论 北京市西城区西长安街社区≥50岁人群防盲及改善低视力工作的重点是白内障、青光眼、DR及屈光不正的早期诊断和治疗.