Prevalence and Causes of Blindness and Low Vision in Khoozestan Province, Iran

To determine the prevalence and causes of blindness and low vision in Khoozestan province in 2006. This population-based cross-sectional study included all residents of Khoozestan province during 2006. The study was designed according to World Health Organization recommendations. Sample size was calculated based on the distribution of the population of Khoozestan according to the national census and estimated rates of blindness. Sampling was performed via multi-stage clustered random method. Information was collected using a questionnaire, including general information and results of optometrist's and ophthalmologist's diagnoses. Initial data accumulation was performed at rural and urban health centres. Categorization of blindness and low vision was based on the International Classification of Diseases version 10 (ICD 10). Overall, 6960 subjects with mean age of 24.7±18.3 years participated in the study (response rate 74.53%). The prevalence of bilateral blindness and low vision among 5-year and older population were 1.3% and 2.6%, respectively with a significant positive trend with age (P<0.001) and no significant difference by sex and residential area. The leading causes of visual impairment included cataracts (39%), refractive errors (37.9%) and amblyopia (23.6%). A minority of cases were due to trauma (1.3%) and surgical complications (1.9%). It is estimated that there are 28537 cases of bilateral blindness and 105995 people with low vision in Khoozestan province. The prevalence of blindness and low vision in this province is in an average rate as compared to similar countries. We recommend performing similar studies throughout the country and reinforce the need for expansion of health programs on prevention and control of visual impairment. These studies are necessary for the appropriate design of Vision 2020 program in Iran.