The Sivaganga Eye Survey: I. Blindness and cataract surgery

PURPOSE To assess the prevalence of visual acuity impairment, blindness, and cataract surgery among older adults in rural southern India. METHODS Random selection of village- and urban-based clusters was used to identify a cross-sectional sample of persons 50 years of age or older from the Sivaganga district of Tamil Nadu. Subjects in 25 selected clusters were enumerated through a door-to-door survey and invited to examination sites for measurement of uncorrected, presenting, and best-corrected visual acuity and ocular examination in 1999. The principal cause was identified for eyes with presenting visual acuity worse than 6/18. Quality assurance monitoring of visual acuity measurements took place in five of the study clusters. RESULTS A total of 5081 persons in 3517 households were enumerated, and 4642 (91.4%) were examined. Thirty-six percent presented with visual acuity worse than 6/18 in the better eye. The prevalence of blindness, based on visual acuity worse than 6/60 in both eyes, was 6.0% (95% confidence interval [CI]: 5.1% to 6.9%) with presenting vision, and 2.5% (95% CI: 1.8% to 3.1%) with best correction. Blindness with presenting visual acuity was associated with older age and illiteracy. Cataract was the principal cause of blindness in one or both eyes in 69.4% of those presenting blind, and uncorrected aphakia and other refractive error affected 35.6% in at least one eye. The prevalence of cataract surgery was 14.7% (95% CI: 13.0% to 16.4%); low surgical coverage among the cataract blind was associated with illiteracy. CONCLUSION It appears that much has been done in the prevention of blindness in Sivaganga. Nevertheless, blindness remains an important public health problem, mainly because of cataract and refractive error. Prevention of blindness programs in the area should target these two causes, with special emphasis on the elderly and the illiterate.     

A population based eye survey of older adults in Tirunelveli district of south India: blindness, cataract surgery, and visual outcomes

AIMS: To assess the prevalence of vision impairment, blindness, and cataract surgery and to evaluate visual acuity outcomes after cataract surgery in a south Indian population. METHODS: Cluster sampling was used to randomly select a cross sectional sample of people > or =50 years of age living in the Tirunelveli district of south India. Eligible subjects in 28 clusters were enumerated through a door to door household survey. Visual acuity measurements and ocular examinations were performed at a selected site within each of the clusters in early 2000. The principal cause of visual impairment was identified for eyes with presenting visual acuity <6/18. Independent replicate testing for quality assurance monitoring was performed in subjects with reduced vision and in a sample of those with normal vision for six of the study clusters. RESULTS: A total of 5795 people in 3986 households were enumerated and 5411 (93.37%) were examined. The prevalence of presenting and best corrected visual acuity > or =6/18 in both eyes was 59.4% and 75.7%, respectively. Presenting vision <6/60 in both eyes (the definition of blindness in India) was found in 11.0%, and in 4.6% with best correction. Presenting blindness was associated with older age, female sex, and illiteracy. Cataract was the principal cause of blindness in at least one eye in 70.6% of blind people. The prevalence of cataract surgery was 11.8%-with an estimated 56.5% of the cataract blind already operated on. Surgical coverage was inversely associated with illiteracy and with female sex in rural areas. Within the cataract operated sample, 31.7% had presenting visual acuity > or =6/18 in both eyes and 11.8% were <6/60; 40% were bilaterally operated on, with 63% pseudophakic. Presenting vision was <6/60 in 40.7% of aphakic eyes and in 5.1% of pseudophakic eyes; with best correction the percentages were 17.6% and 3.7%, respectively. Refractive error, including uncorrected aphakia, was the main cause of visual impairment in cataract operated eyes. Vision <6/18 was associated with cataract surgery in government, as opposed to that in non-governmental/private facilities. Age, sex, literacy, and area of residence were not predictors of visual outcomes. CONCLUSION: Treatable blindness, particularly that associated with cataract and refractive error, remains a significant problem among older adults in south Indian populations, especially in females, the illiterate, and those living in rural areas. Further study is needed to better understand why a significant proportion of the cataract blind are not taking advantage of free of charge eye care services offered by the Aravind Eye Hospital and others in the district. While continuing to increase cataract surgical volume to reduce blindness, emphasis must also be placed on improving postoperative visual acuity outcomes.     

A population-based eye survey of older adults in a rural district of Rajasthan: II. Outcomes of cataract surgery

PURPOSE: To assess the outcomes of cataract surgery in rural northwest India. DESIGN: Population-based, cross-sectional study. PARTICIPANTS: A total of 549 cataract-operated persons (723 operated eyes). METHODS: Cluster sampling was used in randomly selecting a cross-sectional sample of persons 50 years of age or older for visual acuity measurement, refraction, and slit-lamp and direct ophthalmoscope examination early in 1999. Those operated on for cataract were queried as to the date and place of surgery. The principal cause of reduced vision was identified for all examined eyes with presenting visual acuity worse than 6/18. MAIN OUTCOME MEASURES: Presenting and best-corrected visual acuity and cause of vision loss. RESULTS: Presenting visual acuity was less than 6/60 in the better eye in 33.7% of cataract-operated persons and greater than or equal to 6/18 in both eyes in 8.2%; 31.7% were bilaterally operated on. Of cataract-operated eyes, 44.1% initially had visual acuity less than 6/60 and 31.5% greater than or equal to 6/18; with best correction, the corresponding percentages were 14.0% and 61.5%. Intracapsular cataract extraction was used in 92% of cases, and 66% had been operated on in surgery camps. Surgical complications were common and a major cause of vision impairment. In multiple logistic regression modeling, female gender and residence in a rural area were associated negatively with both presenting and best-corrected visual acuity outcomes, and surgery conducted before 1990 was associated negatively with best-corrected visual acuity. Place of surgery and subject schooling were not associated with vision outcomes. CONCLUSIONS: Cataract surgery subjects in rural areas of India that are without adequately equipped facilities and skilled surgeons, and lack of availability of intraocular lenses, are not realizing the full sight-restoring potential of modern-day surgery. Emphasis on the quality of cataract surgery outcomes must be increased to keep pace with that being given to increasing surgical volume.     

2009年上海市宝山区大场社区60岁及以上人群盲和低视力患病率调查

目的 探讨上海市宝山区大场社区60岁及以上人群的盲和低视力患病率、致盲原因及其相关因素。方法 横断面现况调查研究。由上海市眼病防治中心和上海市宝山区疾病预防控制中心于2009年10至12月期间对上海市宝山区大场社区60岁及以上并在当地居住10年以上的常住户籍人口进行随机整群抽样调查。对调查对象完成视力、眼压、验光、裂隙灯显微镜、免散瞳数字眼底照相等检查,采用世界卫生组织视力损伤标准和日常生活视力和视力损伤标准确立盲或低视力,并明确主要致盲原因。组间率的比较采用卡方检验。结果 实际受检4545人,受检率为87.42％。受检人群均为近10年内随着城市化进程从原农村人口转变而来的城市人口。按照世界卫生组织视力损伤标准：双眼盲30人,患病率0.67％;双眼低视力145人,患病率3.19％。白内障、黄斑变性、眼球萎缩或缺如、青光眼、糖尿病视网膜病变（或角膜病）是前5位致盲眼病。女性低视力患病率高于男性,差异有统计学意义(x2 =4.88,P＜0.05)。按照日常生活视力和视力损伤标准：双眼盲39人,患病率0.86％,双眼低视力401人,患病率8.82％;75岁后成为视力损害的高速发展期。白内障、未矫正的屈光不正、黄斑变性、眼球萎缩或缺如、青光眼是前5位致盲原因。女性低视力患病率高于男性,差异有统计学意义(x2=13.345,P＜0.01)。结论 在上海市城市化进程较快的老龄化社区中,白内障、未矫正的屈光不正、黄斑变性是引起日常生活视力盲的前3位原因,女性低视力患病率明显高于男性。对这类社区居民需要进行更多的有针对性眼的保健教育与服务工作。     

Prevalence and vision-related outcomes of cataract surgery in Gujarat,India

Purpose: Investigate the prevalence and vision-related outcomes of cataract surgery in an area of high cataract surgical rate.

Methods: Cluster sampling was used in randomly selecting individuals ≥ 50 years of age in 2007. Participants were queried regarding year and place of previous cataract surgery. Cataract surgical procedures and evidence of surgical complications were recorded. The principal cause was identified for eyes presenting with visual acuity (VA) ≤ 20/40.

Results: A total of 4,738 persons were examined and 834 (17.6%) had cataract surgery. Intra-ocular lenses (IOLs) were used in 84.1% of the 1,299 cataract-operated eyes, with more than half of these having manual small incision surgery. Surgical coverage among the cataract blind (visual acuity [VA] < 20/200) was estimated as 72.2%. Coverage was associated with older age, literacy, and urban residence; gender was not significant. Among cataract-operated eyes, 18.7% presented with VA ≥ 20/32 and 18.0% were < 20/200. With best-corrected acuity, the corresponding percentages were 55.7% and 11.0%. Presenting and best-corrected VA ≥ 20/63 were associated with young age, literacy, and IOL surgery; urban residence and surgery in non-governmental organizations (NGO)/private facilities were also significant for presenting VA; and recent surgery was significant for best-corrected VA. Refractive error was the main cause of vision impairment/blindness in cataract-operated eyes.

Conclusions: Refractive error and posterior capsule opacification, easily treatable causes of visual impairment, are common among the operated. A greater emphasis on the quality of visual acuity outcomes along with sustained efforts to provide access to affordable surgery is needed.     

Rapid assessment of avoidable blindness and needs assessment of cataract surgical services in Satkhira District, Bangladesh

AIMS: To estimate the magnitude and causes of blindness in people aged > or =50 years in Satkhira district, Bangladesh, and to assess the availability of cataract surgical services. METHODS: 106 clusters of 50 people aged > or =50 years were selected by probability-proportionate to size sampling. Households were selected by compact segment sampling. Eligible participants had their visual acuity measured. Those with visual acuity <6/18 were examined by an ophthalmologist. A needs assessment of surgical services was conducted by interviewing service providers. RESULTS: 4868 people were examined (response rate 91.9%). The prevalence of bilateral blindness was 2.9% (95% confidence interval (CI) 2.4% to 3.5%), that of severe visual impairment was 1.6% (95% CI 1.2% to 2.0%) and that of visual impairment was 8.4% (95% CI 7.5% to 9.3%). 79% of bilateral blindness was due to cataract. The cataract surgical coverage was moderate; 61% of people with bilateral cataract blindness (visual acuity <3/60) had undergone surgery. 20% of the 213 eyes that had undergone cataract surgery had a best-corrected poor outcome (visual acuity <6/60). The cataract surgical rate (CSR) in Satkhira was 547 cataract surgeries per million people per year. CONCLUSIONS: Although the prevalence of blindness and visual impairment was lower than expected, the CSR is inadequate to meet the existing need, and the quality of surgery needs to be improved.     

广东省斗门县50岁以上农民视力分布及致盲原因调查

目的 调查广东省斗门县５０岁以上农民视力状况及致盲原因。方法 对广东省斗门县５０岁以上农民进行视力抽样调查。在９５％的可信限、０．３６％允许误差、１．２５抽样作用系数及８５％应答率的条件下,采用整群随机抽样。视力检查采用糖尿病视网膜早期治疗研究视力表测定日常生活视力,由眼科医生做外眼、前房、晶体、眼底、眼压等检查,对所有视力〈０．３的患眼进行主要致病原因的诊断。由两个组经预试验检测一致性满意后,执     

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.     

A survey of blindness and cataract surgery in Doumen County, China.

PURPOSE: To assess blindness prevalence and that caused specifically by cataract in rural southern China. DESIGN: Population-based, cross-sectional study. PARTICIPANTS: A total of 5342 persons older than 50 years of age. METHODS: Visual acuity and eye examinations were performed in the summer of 1997 in a random sample of villages in Doumen County. Differences in blindness prevalence associated with age, gender, and education were explored using logistic regression. The survey was preceded by a pilot study in which operational methods were refined and quality assurance measures were performed. MAIN OUTCOME MEASURES: Distance visual acuity and lens status. RESULTS: Bilateral blindness (presenting visual acuity < 0.10) was found in 4.37% (95% confidence interval, 3.67%-5.06%). Blindness was associated with increasing age (P < 0.001) and with the lack of education (P < 0.01). Cataract was the principal cause of blindness in at least one eye in 61.5% of blind people, with refractive error responsible for another 10%. An estimated 40% of the cataract blind were operated on; surgical coverage was lowest among the elderly, women, and those without schooling, although not at statistically significant levels. CONCLUSIONS: Despite the increased attention given to eye care in Doumen County, blindness remains a major public health problem. Cataract surgery is reaching fewer than half of those who could benefit from it.     

Relationship between vision impairment and eye disease to vision-specific quality of life and function in rural India: the Aravind Comprehensive Eye Survey

PURPOSE: To determine the impact of vision impairment and eye diseases on vision-specific quality of life and visual function in an older population of rural southern India. METHODS: Presenting and best-corrected visual acuity and burden of eye diseases were determined in a population aged 40 years and older, identified through a random cluster sampling strategy from 50 villages of rural south India. A questionnaire validated previously for use in this population was used to ascertain quality of life and visual function. Visual acuity measurements were obtained with illiterate E Early Treatment Diabetic Retinopathy Study (ETDRS) charts. Cataract was graded and defined based on the Lens Opacities Classification System (LOCS) III. Macular degeneration was defined based on the classification system proposed by the International ARM Epidemiologic Study Group. Glaucoma was defined based on results of clinical examinations including optic disc and visual fields. Analyses were performed to explore the relationship of overall and subscale quality-of-life and visual function scores with presenting acuity in the better-seeing eye, specific eye diseases, and demographic variables. RESULTS: Information on quality of life and visual function were available for 5119 (99.4%) of 5150 study subjects. The mean presenting visual acuity in the better eye was 0.76 +/- 0.53 logMAR (logarithm of the minimum angle of resolution) units. Age, education, occupation, presenting acuity in the better eye, and presence of a cataract, glaucoma, or refractive error were independently associated with overall quality-of-life and vision function scores. After adjustment for demographic variables and ocular disease, persons with vision impairment or bilateral blindness based on presenting visual acuity had lower scores across all domains of quality of life and vision function. Scores for subscales of quality-of-life and vision function domains were significantly lower among those with age-related cataract and glaucoma compared with persons without those eye diseases. CONCLUSIONS: Presenting vision in the better eye was associated with quality of life and vision function in this older population of rural south India. Subjects with glaucoma and age-related cataract had an associated decrease in quality of life and vision function, independent of presenting visual acuity in the better eye.     

Blindness and vision impairment in a rural south Indian population: the Aravind Comprehensive Eye Survey

OBJECTIVE: To determine the prevalence of blindness and vision impairment in a rural population of southern India. DESIGN: A population-based cross-sectional study. PARTICIPANTS: A total of 17200 subjects aged 6 years or older, including 5150 subjects aged 40 years or older from 50 clusters representative of three southern districts of Tamil Nadu in southern India. METHODS: All participants had preliminary screenings consisting of vision using a LogMAR illiterate E chart and anterior segment hand light examinations at the village level. Subjects aged 40 years or older were offered comprehensive eye examinations at the base hospital, including visual acuity using LogMAR illiterate E charts and refraction, slit-lamp biomicroscopy, gonioscopy, applanation tonometry, dilated fundus examinations, and automated Humphrey central 24-2 full threshold perimetry; subjects younger than 40 years of age who had any signs or symptoms of ocular disease were also offered comparable examinations at the base hospital. MAIN OUTCOME MEASURES: Visual impairment was defined as best-corrected visual acuity <6/18, and blindness was defined using both Indian (<6/60) and World Health Organization (<3/60) definitions. RESULTS: Comprehensive examinations at the base hospital were performed on 5150 (96.5%) of 5337 persons 40 years of age or older. Among those 40 years of age and older, presenting visual acuity at the <3/60 level was present in 4.3% (95% confidence interval [CI]: 3.8, 4.9) and 11.4% (95% CI: 10.6, 12.3) at the <6/60 level. After best correction, the corresponding figures were 1.0% (95% CI: 0.79, 1.2) and 2.1% (95% CI: 1.7, 2.5). Over 70% of subjects improved their vision by at least one line, and nearly a third by three lines after refraction. Age-related cataract was the most common potentially reversible blinding disorder (72.0%) among eyes presenting with blindness. CONCLUSIONS: Blindness and vision impairment remain major public health problems in India that need to be addressed. Cataracts and refractive errors remain the major reversible causes for the burden of vision impairment in this rural population.     

南通市新城桥街道60岁及以上人群盲和低视力的现况调查

目的调查江苏省南通市城市人口中60岁及以上人群盲和低视力的患病率及其原因。方法采用随机整群抽样方法,抽取新城桥街道14个社区中的8个,并对所有60岁及以上人群进行检查。分别检查小孔视力和日常生活视力,应用裂隙灯显微镜和直接检眼镜等仪器检查受检者外眼、眼前节及眼底等情况。正式调查前先进行预试验。结果共检录3352人,受检人数为3040人,应答率90．69％。按小孔视力和世界卫生组织视力损伤标准,双眼盲和低视力患病率分别为1．35％和1．84％,其中女性分别为1．92％和2．33％,男性为0．66％和1．24％;盲和低视力患病率随着年龄的增长而增加;致盲和低视力的首要原因为白内障。按日常生活视力和视力损伤标准,双眼盲和视力损伤的患病率分别为1．58％和13．59％,其中女性分别为2．10％和15．98％,男性为0．95％和10．66％;盲和视力损伤的患病率亦随年龄的增长而增加;致双眼盲的首要原因亦为白内障。结论南通市60岁及以上城市人群盲的患病率低于华北、华南及西部地区。女性与文盲的盲和低视力患病率分别高于男性与非文盲。南通市城市人口中致盲的主要原因依次为白内障、眼底异常、屈光不正及角膜瘢痕或混浊等。     

Prevalence of visual impairment, blindness, and cataract surgery in the Hong Kong elderly

BACKGROUND: The prevalence of vision impairment, unilateral/bilateral blindness, and cataract surgery were estimated in a population based survey among the elderly in a suburban area of Hong Kong. METHODS: 15 public, private, and home ownership scheme housing estates in the Shatin area of Hong Kong were subjected to cluster sampling to randomly select a cross section of people 60 years of age or older. Visual acuity measurements and ocular examinations were conducted at a community site within each estate. The principal cause of reduced vision was identified for eyes with presenting visual acuity worse than 6/18. RESULTS: A total of 3441 subjects from an enumerated population of 4487 (76.7%) completed an eye examination. The prevalence of presenting visual acuity less than 6/18 in at least one eye was 41.3%; and 73.1% in those 80 years of age or older. Unilateral blindness (acuity <6/60) was found in 7.9% of subjects and bilateral blindness in 1.8%. Refractive error and cataract were, respectively, the main causes of vision impairment and blindness. Visual impairment with either eye <6/18 increased with advancing age and was more prevalent in males, the less educated, and those living in public housing estates. The prevalence of cataract surgery was 9.1% and was associated with advancing age and less education. CONCLUSIONS: Blindness and visual disability were common in this socioeconomically advanced population, with most of it easily remedied. Because of a rapidly ageing population, healthcare planners in Hong Kong must prepare for an increasing burden of visual disability and blindness.     

拉萨市林周县40岁及以上人群中盲的患病率调查

目的：调查拉萨市林周县40岁及以上人群中的盲患病率。方法：2000年4－6月采用整群抽样方法,抽取林周县44个自然村40岁及以上人群3153人进行视力及眼部检查,根据小孔视力和世界卫生组织视力损伤标准（标准A）及日常生活视力和视力损伤标准(标准B）计算盲的患病率。结果：在应受检的3153人中,实际接受检查人数为3071人,受检率为97．4％。（1）以标准A计算盲的患病率：双眼盲的患病率为2．3％（95％可信区间：1．8－2．8）;盲的患病率随年龄增长而增加（P＜0．001）;男性高于女性,差异无显著意义（P＞0．05）,调整年龄后差异有显著意义（P＜0．05）;文盲中盲的患病率高于非文盲者,差异有显著意义（P＜0．001）,调整年龄后差异无显著意义（P＞0．05）;文盲中盲的患病率高于非文盲者,差异有显著意义（P＜0．001）,调整年龄后差异无显著意义（P＞0．05）。（2）以标准B计算盲的患病率：盲的患病率为3．2％（95％可信区间：2．6－3．8）;盲的患病率亦随年龄增长而增加（P＜0．001）;男与女盲的患病率优势比值为1．2,差异无显著意义（P＞0．05）,调整年龄后差异无显著意义（P＜0．001）;男与女盲的患病率优势比值为1．2,差异无显著意义（P＞0．05）,调整年龄后差异无显著意义（P＞0．05）;文盲中盲的患病率高于非文盲者,差异有显著意义（P＜0．001）,调整年龄后差异无显著性（P＞0．05）。结论：高原地区盲的患病率高于内地。白内障是盲的主要原因。     

北京市顺义县50岁及以上人群中盲患病率调查

目的 调查北京市顺义县５０岁及以上人群盲患病率,并与１９８５年调查结果相比较,以此评价近１０余年该县实施防盲治项目的效果。方法 １９９６年９～１１月采用整群随机抽样方法在顺义县抽取２８个调查点,对５０岁及以上人群进行视力和眼部检查。正式现场调查之前先进行预试验,并进行保证调查质量的重复性检验。结果 检录５５５５例中,受检人数为５０８４例,受检率为９１．５％。以世界卫生组织视力损伤为标准,盲患病率为     

Rapid Assessment of Avoidable Blindness and Cataract Surgical Services in Kilimanjaro Region,Tanzania

Purpose: To estimate the prevalence and causes of avoidable blindness and visual impairment in persons 50 years of age and older, and to assess the impact of cataract surgical services.

Methods: In this cross-sectional population-based survey, 72 clusters of 50 people 50 years and older were selected by probability proportionate to size sampling. Households within clusters were selected through compact segment sampling. Participants underwent an ophthalmic examination in their homes, including measurement of visual acuity (VA) with a tumbling-E chart and diagnosis of the principal cause of visual impairment. Patients who had been operated on were questioned about details of their cataract surgery.

Results: Three thousand six hundred eligible subjects were selected, of whom 3,436 (95.5%) were examined. The prevalence of bilateral blindness (presenting VA < 3/60) was 2.4% (95% confidence interval [CI], 1.9%–2.9%); prevalence of severe visual impairment was 0.99% (95% CI, 0.98%–0.99%); and prevalence of visual impairment (VA of <?6/18 and ≥ 6/60) was 5.4% (95% CI, 4.6%–6.2%) in the sample. Unoperated cataract accounted for 52.4% of blindness and 70.6% of severe visual impairment. Cataract surgical coverage among people at 3/60 was 68.9%. Overall, 58.6% and 69.6% of the 191 eyes that had undergone cataract surgery had VA greater than or equal to 6/18 with available correction and best correction respectively.

Conclusions: The prevalence of blindness in this population in Kilimanjaro Region was low, reflecting high cataract surgical coverage from an outreach program. Even with high cataract surgical coverage, cataract remains the leading cause of vision loss and an emphasis on quality is needed.     

Prevalence and causes of blindness in the rural population of the Chennai Glaucoma Study

AIM: To study the prevalence and causes of blindness in a rural south Indian population. METHODS: 3924/4800 enumerated (81.75%) subjects, aged 40 years or more from rural Tamil Nadu, underwent comprehensive ophthalmic examination-visual acuity, refraction, intraocular pressure, gonioscopy, cataract grading (LOCS II), retinal examination, and SITA Standard where indicated. Blindness was defined using WHO criteria as best corrected visual acuity of less than 3/60 and/or visual field of less than 10 degrees in the better eye. The influence of age, sex, literacy, and occupation was assessed using multiple logistic regression. RESULTS: 753 subjects (19.2%; 321 males, 432 females) presented with a visual acuity of <3/60; 132 subjects (3.36%, 95% CI: 2.80 to 3.93) were diagnosed to be blind. Cataract was responsible in 74.62% of eyes; glaucoma, cystoid macular oedema, optic atrophy, and corneal scars accounted for 3.79% each. Bilateral causes of blindness were cataract (78.63%), glaucoma (4.29%), optic atrophy (3.42%), cystoid macular oedema, and corneal scars (2.56% each). In 19 eyes (7.2%) the blindness was probably related to cataract surgery. Blindness was positively associated with increasing age (p<0.0001). CONCLUSION: 3.36% of the studied rural population was bilaterally blind, with cataract being the single most important cause.     

Blindness and vision impairment in the elderly of Papua New Guinea

BACKGROUND: To estimate the magnitude and causes of blindness and vision impairment in Papua New Guinea for service delivery planning and ophthalmic education development. METHODS: Using the World Health Organization standardized Rapid Assessment of Cataract Surgical Services protocol, a population-based cross-sectional survey was conducted in 2005. By systematic, two-stage cluster random sampling, 39 clusters each of 30 people aged 50 years and over were selected from urban and rural locations. A cause of vision loss was determined for each eye with a presenting visual acuity worse than 6/18. RESULTS: Of the 1191 people enumerated, 1174 were examined (98.6%). The 50 years and older age-gender adjusted prevalence of vision impairment (presenting visual acuity less than 6/18 in the better eye) was 29.2% (95% Confidence Interval [CI]: 27.6, 35.1, Design Effect [deff] = 2.3). That of functional blindness (presenting visual acuity less than 6/60 in the better eye) was 8.9% (95% CI: 8.4, 12.0, deff = 1.2), and of World Health Organization blindness (but presenting, rather than best corrected, visual acuity of less than 3/60 in the better eye) was 3.9% (95% CI: 3.4, 6.1, deff = 1.0). Uncorrected refractive error (13.1%, 95% CI: 11.3, 15.1, deff = 1.2) and cataract (7.4%, 95% CI: 6.4, 10.2, deff = 1.3) were leading causes of vision impairment, age-gender adjusted. Cataract was the most common (age-gender adjusted 6.4%, 95% CI: 5.1, 7.3, deff = 1.1) cause of functional blindness. On bivariate analysis, increasing age (P < 0.001), illiteracy (P < 0.001) and unemployment (P < 0.001) were associated with functional blindness. Gender was not. CONCLUSIONS: The identification and treatment of refractive error and cataract need to be priorities for eye health services in Papua New Guinea if the burden of vision impairment and blindness is to be diminished. The education of community and hospital eye care providers, whether medical, nursing or other cadres, must emphasize these. Eye care services must be structured and provided to allow and encourage accessibility and uptake, with satisfactory treatment outcomes for these conditions.     

Cataract blindness and barriers to uptake of cataract surgery in a rural community of northern Nigeria

AIMS: A population based cross sectional survey was conducted to determine the magnitude of cataract blindness and the barriers to uptake of cataract services in a rural community of northern Nigeria. METHODS: 1461 people out of 1924 registered eligible people were examined. The study population was chosen by two stage cluster random sampling. In the first sampling stage 15 villages were randomly chosen while in the final stage 170 people who were 40 years and over were selected in each village. Each selected person had visual acuity recorded for both eyes. Those with vision of less than 3/60 in the better eye were assessed for cataract. People with cataract were asked why they had not sought medical attention. RESULTS: A blindness prevalence of 8.2% (95% CI 5.8%-10.5%) was found among the sampled population. Cataract was responsible for 44.2% of the blindness. Thus, a cataract blindness prevalence of 3.6% was found. The cataract surgical coverage (people) was 4.0% and the couching coverage (people) was 18%. The main barrier to seeking cataract surgery was cost of the service (61%). CONCLUSION: Some regions of the world still have high burden of cataract blindness that needs attention. Such areas need an effective free cataract outreach programme.     

Four-year incidence of visual impairment: Barbados Incidence Study of Eye Diseases

OBJECTIVE: To describe the 4-year incidence of visual impairment and causes of blindness among black participants of the Barbados Eye Studies. DESIGN: Population-based incidence study. SETTING AND PARTICIPANTS: The Barbados Incidence Study of Eye Diseases (BISED) followed the cohort of the Barbados Eye Study (BES), a prevalence study based on a simple random sample of Barbadians 40 to 84 years of age. BISED included 3193 black participants from the original cohort (85% of those eligible). MAIN OUTCOME MEASURES: Best-corrected visual acuity (Ferris-Bailey chart) at baseline and follow-up was measured according to a modified Early Treatment of Diabetic Retinopathy Study protocol. By use of World Health Organization (WHO) criteria, low vision and blindness for an individual were defined as visual acuity (VA) <6/18 to 6/120 and <6/120, respectively, in the better eye. By commonly used US criteria, low vision and blindness were defined as VA < or = 20/40 and < or = 20/200, respectively. Vision loss was defined as a doubling of the visual angle (i.e., decrease of 15 letters or more read correctly between baseline and follow-up examinations). Progression was defined as vision loss among those with low vision at baseline. RESULTS: On the basis of WHO criteria, the overall 4-year incidence was 3.6% (95% confidence interval [CI], 3.0%-4.4%) for low vision and 0.6% (95% CI, 0.4%-1.0%) for blindness. Incidence rates were higher using US criteria: 5.3% (95 % CI, 4.5%-6.2%) and 1.5% (95% CI, 1.1%-2.0%), respectively, reaching 21.5% and 7.3% for persons aged 70 years or older at baseline. One tenth of the cohort had vision loss, and 28.6% of those with low vision progressed. About one half of incident blindness was due to age-related cataract. Nearly one fifth was caused by open-angle glaucoma (OAG) alone or combined with cataract, and approximately 10% was caused by diabetic retinopathy (DR). CONCLUSIONS: The incidence of visual impairment was high in this Afro-Caribbean population, particularly in older age groups, indicating the public health significance of visual loss for this and similar black populations. Cataract, OAG, and DR were among the leading causes of incident blindness, paralleling their high prevalence in this population.