Age-specific prevalence and causes of bilateral and unilateral visual impairment in older Australians: the Blue Mountains Eye Study

Purpose : To report age‐specific prevalence and causes of bilateral and unilateral visual impairment in a representative older Australian population. Methods : Participants in the Blue Mountains Eye Study (n = 3654) underwent a detailed eye examination. Any visual impairment was defined as best‐corrected visual acuity (VA) of 6/12 or worse, moderate impairment as VA 6/24–6/60 and severe impairment as VA worse than 6/60 (the Australian definition for legal blindness). Bilateral visual impairment was defined from the better eye and unilateral impairment from the worse eye. Proportional causes for visual loss were determined by the examining ophthalmologist. Results : Prevalence of bilateral and unilateral visual impairment was strongly age related. Corresponding bilateral and unilateral visual impairment prevalence rates were, respectively, 0.6% and 3.6% for persons aged 49–59 years, 1.1% and 8.2% for ages 60–69, 5.4% and 20.1% for ages 70–79, and 26.3% and 52.2% for persons aged 80+ years. Overwhelmingly, age‐related maculopathy (ARM) was the predominant cause of bilateral blindness (13/17) and of moderate to severe bilateral visual impairment in persons aged 70+ years. However, cataract was the most frequent cause of mild bilateral visual impairment among persons aged 60+ years. Amblyopia was the most frequent cause of mild or worse unilateral visual impairment in persons aged 49–59 years. Cataract was the most common cause of mild unilateral visual impairment in people aged 60+ years, while ARM and cataract were jointly the most frequent causes of moderate to severe unilateral visual impairment in people aged 70+ years. Conclusions : These findings indicate that around half of visually impaired persons aged 60 years or over had cataract, a cause amenable to treatment.     

北京市顺义区白内障患病和手术状况的调查

目的　调查北京市顺义区50岁及以上人群中白内障患病率、白内障盲人手术覆盖率和白内障盲人社会负担率,以此了解白内障的患病状况及评价10余年来该区实施以白内障手术治疗为主的防盲治盲工作的效果。方法　1996年9月,采用整群随机抽样方法对顺义区抽取28个调查点5084例50岁及以上人群进行视力和眼部检查,包括应用裂隙灯检查受检者晶状体;了解接受白内障手术的情况。结果　5084例受检者中,白内障患病率为23.31%。随着年龄的增加,白内障患病率明显增高。在女性和文盲者中的白内障患病率较高,分别为26.01%及37.33%;1984年后,白内障手术率持续增加,以双眼小孔视力＜0.05作为盲的标准,白内障手术覆盖率为56.36%,白内障盲人的社会负担率为1.63%。以双眼日常生活视力<0.1为标准,白内障手术的覆盖率为47.79%,白内障盲人的社会负担率为2.22%。在70岁以上人群、女性和文盲者中,白内障手术覆盖率较低,分别为36.36%、44.87%及44.09%。白内障盲人的社会负担率较高,分别为6.84%、2.74%及3.90%。结论白内障仍是高龄者的致盲眼病,白内障盲人所造成的社会负担较重。在老龄、女性及文盲中因白内障引起的盲目仍是顺义区目前存在的严重问题。     

Cataract blindness and visual outcome of cataract surgery in a tribal area in Pakistan

AIM: To estimate the rates of cataract blindness and cataract surgical coverage and to assess the visual outcome of cataract surgery among individuals aged > or =50 years in Orakzai Agency, Pakistan. METHODS: 1600 individuals aged > or =50 years were selected using probability proportional to size sampling. The main outcome measure was bilateral cataract blindness which was defined as visual acuity of <3/60 in the better eye with best available correction and with obvious central lens opacities/absence of red reflex in both eyes. RESULTS: A total of 1549 people were examined; the coverage rate was 96.8%. Of individuals who were examined, 958 (61.8%) were men. The overall prevalence of bilateral cataract blindness was 4.8% (95% CI: 3.8% to 5.9%). Women had a 2.1-fold greater prevalence of bilateral cataract blindness than men (7.1% (5.0% to 9.2%) v 3.4% (2.3% to 4.6%); p = <0.0001). However, cataract surgical coverage rates were lower for women than men. The overall quality of previous cataract surgery was poor: 43.1% eyes with cataract surgery had VA <6/60. 73.3% people with bilateral cataract blindness reported they could not undergo cataract surgery because they were too poor to afford its cost. CONCLUSION: The unacceptably high rates of cataract blindness and poor affordability and visual outcome of cataract surgery calls for the establishment, in the agency, of static cataract surgical services that are high quality, affordable, and gender sensitive.     

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.     

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.     

Cataract surgical coverage: Results of a population-based survey at Nkhoma,Malawi

AIM. To determine the cataract surgical coverage (CSC) in the close proximity of Nkhoma Hospital, Malawi. METHOD. A rapid epidemiological assessment of the population aged 40 years and over was undertaken to determine the proportion of eyes and patients with cataract blindness that had previously received cataract surgery within a 10-mile radius of the hospital. RESULTS. A total of 993 people aged 40 years and above from all 31 small villages in the 10-mile radius were examined. The prevalence of blindness in this age group was 3.72%, of which 62% was due to cataract. The cataract surgical coverage for people with blinding cataract was calculated at 14.8%, and for eyes with cataract (visual acuity &lt;3/60) 8.5%. CONCLUSION. Nkhoma Hospital has provided affordable cataract surgery for more than 20 years. Despite this, within a ten-mile radius of the hospital, only 1 in 7 people with bilateral blindness from cataract has received surgery.     

Cataract blindness in Turkmenistan: results of a national survey

AIM: To present results of a rapid assessment of cataract in Turkmenistan. METHODS: 6120 eligible people of 50 years and older were selected by systematic random sampling from the whole of Turkmenistan. A total of 6011 people were examined (coverage 98.2%). RESULTS: Cataract is the major cause of bilateral blindness (54%), followed by glaucoma (25%). The age and sex adjusted prevalence of bilateral cataract blindness (VA <3/60) in people of 50 years and older was 0.6% (95% CI: 0.4 to 0.9), with a cataract surgical coverage of 75% (people). For VA <6/60 the prevalence was 2.6% (95% CI: 2.1 to 3.2) in people aged 50 and above, approximately 0.26% of the total population. In this last group the surgical coverage was 44% (people) and 32% (eyes). Of the patients operated with IOL implantation 8.2% could not see 6/60, 44.8% of those operated without IOL could not see 6/60. The main barrier to cataract surgery was indifference ("old age, no need for surgery"), followed by "waiting for maturity." CONCLUSION: To increase the cataract surgical coverage in Turkmenistan the intake criteria should be lowered to VA <6/60 or less. At the same time the visual outcome of surgery can be improved by expanding the number of IOL surgeries and routine monitoring of cataract outcome. Additional investments will be required to provide all eye surgeons with appropriate equipment and skills for IOL surgery.     

甘肃省平凉市崆峒区人群盲和低视力现况调查

目的:探讨与了解甘肃省平凉市崆峒区人群盲与低视力的患病率及致病原因。方法:应用横断面研究的流行病学调查方法,以村(社区)为基础,采用随机整群抽样原则抽取6个乡镇2个街道办事处作为调查地点。采用世界卫生组织制定的盲与低视力标准,对全区按0.719%抽样比例抽取样本进行盲与低视力的流行病学调查。结果:检录3235例中,受检人数为2801例,受检率为86.58%,双眼盲21例,盲率为0.75%(男0.59%,女0.91%);双眼低视力125例,低视力患病率为4.46%(男3.73%,女5.16%),≥60岁以上盲与低视力患者的患病率明显增高。致盲病因前三位的眼病依次为白内障(47.62%)、角膜病(14.29%)、青光眼(14.29%)。结论:崆峒区人群中盲和低视力的眼病以白内障居首位,因此手术治疗白内障仍是今后防盲治盲工作的首要任务。     

Prevalence and causes of blindness and low vision in a rural setting in Pakistan

PURPOSE: To determine the prevalence and causes of blindness and visual impairment in people 40 years of age and older in Budni, Peshawar, Pakistan. METHODS: A population-based cross-sectional study was carried out involving 1,106 men and women 40 years of age and older in a rural area in Pakistan's North West Frontier Province (NWFP). All subjects with a presenting visual acuity < 6/18 in either eye were referred to a centralized clinic for a standardized eye examination that included refraction and dilated fundal examination. The main outcome was blindness (presenting visual acuity < 3/60 in the better eye) and low vision (presenting VA < 6/18-3/60 in the better eye). RESULTS: Of 1,106 people examined, 21 (1.9%; 95% CI: 1.1-2.7%) were blind, while another 27 (2.4%) and 62 (5.5%) subjects had severe visual impairment (< 6/60-3/60) and visual impairment (< 6/18-6/60), respectively. Women, as compared to men, had a higher prevalence of visual impairment and severe visual impairment; but they had a lower prevalence of blindness (1.6 vs. 2.2%); however, the difference was not statistically significant (0.6%; 95% CI: -0.9-2.1%). Similarly farmers had the highest prevalence of blindness. The leading cause of blindness and low vision was cataract, which accounted for 14 of 21 (66.6%) cases of blindness and 49 of 89 (55.5%) cases of low vision. The second leading cause of blindness was uncorrected aphakia. CONCLUSION: Much of the blindness was due to unoperated cataract and uncorrected aphakia. Thus, there is an urgent need to develop ways in which cataract surgical output could be increased, and glasses provided to those who need them.     

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.