An epidemiological survey of blindness and low vision in Chongqing

An epidemiological survey of blindness and low vision in Chongqing showed that in a random sample of 13,832, there were 62 cases of bilateral blindness and 97 cases of bilateral low vision, the prevalences being 0.45% (male 0.38%, female 0.52%) and 0.70% (male 0.50%, female 0.90%) respectively. The prevalences in people over 60 years of age were significantly higher. The important blinding diseases were cataract, infectious keratitis, corneal turbidity, glaucoma, trachoma, and ametropia/amblyopia.     

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.     

广东省梅县盲和低视力流行病学调查

目的 调查梅县盲及低视力的流行病学情况。方法 采用分层随机抽样原因,以世界卫生组织盲目分级为标准,对全县按2.01%抽样比例抽取11327例进行盲和低视力的流行病学调查。结果 双眼盲及低视力患病率分别为0.47%（男性0.30%,女性0.63%）和0.89%（男性0.66%,女性1.12%）;双眼盲率：县城0.29%、附城郊区0.34%、山区0.56%。单眼盲、双眼低视力和单眼低视力的患病率分别为0.72%、0.89%和0.59%。≥50岁盲及低视力患者的患病率明显增高。结论 致盲和致低视力的眼病均以白内障居首位,其次为青光眼、屈光不正、弱视及翼状胬肉等。     

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.     

A survey of blindness and low vision in Shanxi Province

In accordance with the unified criteria and methods over the country, a sampling survey of blindness and low vision was carried out in Shanxi province in April, 1987. The sample population was 53,656 persons and the actual number examined was 51,664 (96.3%). The provincial prevalence of blindness was 0.46%, i.e. 0.18% in cities and 0.50% in rural areas, with senile cataract as the leading cause for blindness (29.7%). The prevalence of monocular blindness was 0.85% and that of low vision 1.23%. The authors also proposed key points for the prevention and treatment of blindness and low vision.     

Prevalence of blindness and low vision: a study in the rural Heilongjiang Province of China

Background: The prevalence of blind individuals in the north of China is unknown. The study aimed to investigate the prevalence and causes of blindness and low vision in rural areas in Heilongjiang province of China in 2008–2009. Design: Cross‐sectional study. Participants or Samples: A cluster random sampling method was used to recruit participants of all ages in rural areas of Heilongjiang. Methods: Trained professionals performed interviews and clinical examinations to measure visual acuity. The relationships between blindness or low vision and age, gender and education level were analysed. Main Outcome Measures: The main outcome measure was prevalence rates of bilateral blindness and bilateral low vision. Results: Of the 11 787 subjects, 10 384 (88.1%) were surveyed. The overall age‐adjusted prevalence rates were 0.7% (95% confidence interval: 0.5–0.8%) for bilateral blindness and 1.7% (95% confidence interval: 1.4–1.9%) for bilateral low vision. The prevalence rates of blindness and low vision were higher in the elderly and uneducated population (P < 0.05). The main causes for blindness and low vision were cataracts (44.1 and 46.0%, respectively) and refractive errors (17.7 and 42.5%, respectively). Conclusion: Blindness and low vision are highly prevalent among people with cataracts and refractive errors. Eye care planning must focus on treating the avoidable and curable forms of blindness.     

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.     

乌鲁木齐市老年公寓中50岁及以上人群盲与低视力调查

目的了解乌鲁木齐市19所正式登记的老年公寓入住50岁及以上人群的盲与低视力构成比及主要致盲原因。设计横断面调查。研究对象乌鲁木齐市19所老年公寓中50岁及以上符合入选标准的475人。方法对符合此次调查准入标准的475人进行常规日常生活视力、小孔视力的检查。筛选出盲和低视力的患者,对其眼病进行相应辅助检查,分析致盲的主要原因。主要指标盲与低视力构成比。结果被调查的475人中,按照A标准:双眼盲构成比为6.9%,双眼低视力的构成比为8.4%,单眼盲构成比为14.9%,单眼低视力构成比为12.0%。按照B标准:视力损伤构成比为17.1%,单眼盲、轻度盲和重度盲构成比分别为15.4%、2.9%和6.9%。致盲的主要病因依次为白内障(59.87%)、屈光不正(11.84%)、眼底病变(15.13%)、角膜混浊(5.92%)、眼球萎缩或缺如(2.96%)、青光眼(2.63%)、不确定(1.64%)。结论乌鲁木齐市老年公寓50岁及以上人群,随年龄增加易患致盲性眼病。白内障为主要致盲原因。     

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.     

Blindness and low vision in a tertiary ophthalmologic center in Thailand: the importance of cytomegalovirus retinitis

PURPOSE: To determine the causes of blindness and low vision in patients consulting a tertiary ophthalmologic center in northern Thailand. METHODS: The study population included 2,951 new consecutive patients from the Department of Ophthalmology at University Hospital in Chiang-Mai, Thailand. Main outcome measures were blindness and low vision, which were defined according to World Health Organization criteria. RESULTS: Of 2,951 patients, 369 (12.5%) had blindness and/or low vision (bilateral blindness in 73, unilateral blindness in 129, bilateral low vision in 77, and unilateral low vision in 90). Of the etiological causes of visual loss, age-related ocular disease was the most frequent (128 patients [35%]) followed by infections (66 patients [18%]) and trauma (43 patients [12%]). Although infections and trauma were the predominant causes of blindness, age-related disorders were frequently found in patients with low vision. Of anatomical sites, the lens (134 patients [36%]) was the main location of visual loss, closely followed by disorders of the retina and/or uvea (126 patients [34%]). Blindness and low vision were considered avoidable in 70% of cases. Of 73 patients with bilateral blindness, 14 had active cytomegalovirus retinitis, accounting for 19% of all patients with bilateral blindness. CONCLUSION: The most common causes of blindness and low vision in a tertiary center in northern Thailand were age-related ocular disorders and infections, which were predominantly cases of cytomegalovirus retinitis in human immunodeficiency virus-infected patients.