[Prevalence and causes of low vision and blindness in the blind population supported by the Yazd Welfare Organization]

In 1995, the World Health Organization [WHO] estimated that there were 37.1 million blind people worldwide. It has subsequently been reported that 110 million people have severely impaired vision, hence are at great risk of becoming blind. Watkins predicted an annual increase of about two million blind worldwide. This study was designed to investigate the causes of blindness and low vision in the blind population supported by the welfare organization of Yazd, Iran. This clinical descriptive cross-sectional study was done from January to September, 2003. In total, 109 blind patients supported by the welfare organization were included in this study. All data was collected by standard methods using questionnaire, interview and specific examination. The data included; demographic characteristics, clinical states, ophthalmic examination, family history and the available prenatal information. The data were analyzed by SPSS software and chi square test. of total patients, 73 cases were male [67%] and 36 were female [33%]. The median age was 24.6 years [range one month to 60 years]. More than half of the cases [53.2%] could be diagnosed in children less than one year of age. In total, 79 patients [88.1%] were legally blind of which 23 cases [29.1%] had no light perception [NLP]. The most common causes of blindness were retinitis pigmentosa [32.1%] followed by ocular dysgenesis [16.5%]. Our data showed that more than half of the blindness cases occur during the first year of life. The most common cause of blindness was retinitis pigmentosa followed by ocular dysgenesis, cataract and glaucoma, respectively