Dandona L, Dandona R, Srinivas M, Mandal P, McCarty C A, Rao G N
Public Health Ophthalmology Service and International Centre for Advancement of Rural Eye Care, L.V. Prasad Eye Institute, Banjara Hills, Hyderabad-500034, India.
Indian J Ophthalmol. 2000 Mar;48(1):59-64.
This study assessed the prevalence and causes of unilateral visual impairment in the urban population of Hyderabad city as part of the Andhra Pradesh Eye Disease Study. Stratified, random, cluster, systematic sampling was used to select 2,954 subjects from 24 clusters representative of the population of Hyderabad. Eligible subjects underwent detailed eye examination including logMAR visual acuity, refraction, slitlamp biomicroscopy, applanation tonometry, gonioscopy, dilatation, cataract grading, and stereoscopic evaluation of fundus. Automated threshold visual fields and slitlamp and fundus photography were done when indicated by standardised criteria. Unilateral visual impairment was defined as presenting distance visual acuity < 6/18 in the worse eye and > or = 6/12 in the better eye, which was further divided into unilateral blindness (visual acuity < 6/60 in the worse eye) and unilateral moderate visual impairment (visual acuity < 6/18-6/60 in the worse eye). A total of 2,522 subjects (85.4% of eligible), including 1,399 > or = 30 years old, participated in the study. In addition to the 1% blindness and 7.2% moderate visual impairment (based on bilateral visual impairment criteria) reported earlier in this sample, 139 subjects had unilateral visual impairment, an age-gender-adjusted prevalence of 3.8% (95% confidence interval 2.7-4.9%). The major causes of this visual impairment 39.9% were refractive error (42.9%), cataract (14.4%), corneal disease (11.5%), and retinal disease (11.2%). Of this unilateral visual impairment was blindness. The major causes of unilateral blindness were corneal disease (23.2%), cataract (22.5%), retinal disease (18%), and optic atrophy (12.9%). On the other hand, the predominant cause of unilateral moderate visual impairment was refractive error (67%) followed by cataract (9%). Of the total unilateral visual impairment, 34.3% was present in those < 30 years old and 36.2% in those 30-49 years old. Unilateral visual impairment afflicts approximately 1 in 25 persons in this urban population. A large proportion of this unilateral visual impairment is present in younger age groups. The causes of unilateral visual impairment, like those of bilateral visual impairment in this population, are varied, suggesting therefore, that in addition to the current focus of eye care in India predominantly on cataract, other causes of visual impairment need to be addressed as well.
作为安得拉邦眼病研究的一部分，本研究评估了海得拉巴市城市人口中单侧视力损害的患病率及病因。采用分层随机整群系统抽样方法，从代表海得拉巴市人口的24个群组中选取了2954名受试者。符合条件的受试者接受了详细的眼科检查，包括对数视力表视力、验光、裂隙灯显微镜检查、压平眼压测量、前房角镜检查、散瞳、白内障分级以及眼底立体评估。当符合标准化标准时，进行自动阈值视野检查以及裂隙灯和眼底照相。单侧视力损害定义为较差眼的远视力<6/18且较好眼的远视力≥6/12，进一步分为单侧盲（较差眼视力<6/60）和单侧中度视力损害（较差眼视力<6/18 - 6/60）。共有2522名受试者（占符合条件者的85.4%）参与了研究，其中包括1399名年龄≥30岁的受试者。除了此前在该样本中报告的1%的盲和7.2%的中度视力损害（基于双侧视力损害标准）外，有139名受试者存在单侧视力损害，年龄和性别调整后的患病率为3.8%（95%置信区间2.7 - 4.9%）。这种视力损害的主要原因包括屈光不正（42.9%）、白内障（14.4%）、角膜疾病（11.5%）和视网膜疾病（11.2%）。其中单侧视力损害中有部分是盲。单侧盲的主要原因是角膜疾病（23.2%）、白内障（22.5%）、视网膜疾病（18%）和视神经萎缩（12.9%）。另一方面，单侧中度视力损害的主要原因是屈光不正（67%），其次是白内障（9%）。在所有单侧视力损害中，34.3%出现在年龄<30岁的人群中，36.2%出现在30 - 49岁的人群中。在这个城市人口中，约每25人中就有1人患有单侧视力损害。很大一部分单侧视力损害出现在较年轻的年龄组中。与该人群双侧视力损害的病因一样，单侧视力损害的病因多种多样，因此这表明，除了印度目前主要关注的白内障外，其他视力损害病因也需要得到解决。
