[Prevalence and causes of blindness and visual impairment in varamin district]

ABSTRACT

To estimate the magnitude and causes of visual impairment [VI] in subjects aged >/= 50 years in Varamin district in 2009 using the proposed method by the World Health Organization [WHO]. This cross sectional population based survey was performed in Varamin targeting people over the age of 50 years using the proportional probabilities to size and cluster compact segment sampling method. Blindness was defind by WHO definition as best corrected visual acuity [VA] in the better eye less than 3/60. Severe visual impairment [SVI] and visual impairment [VI] were defined as 3/60eye, respectively. The cause of visual impairment was determined in any eye with VA<6/18. The results were analyzed by RAAB software. Among 3,000 selected patients, 2,819 persons [94% response rate] including 45.7% men and 54.3% women were examined. The standardized prevalence of blindness, severe visual impairment [SVI] and visual impairment [VI] were 1.33 +/- 0.43, 1.34 +/- 0.55 and 6.84 +/- 0.95, respectively. More than 75% of causes of blindness, SVI and VI were avoidable. The principal cause of blindness and SVI was cataract; although, in VI it was refractive errors. The majority of blindness and VI was due to avoidable causes. Cataract and refractive errors were the main causes in the studied population