Prevalence and causes of blindness & low vision; before and five years after 'VISION 2020' initiatives in Oman: a review

BACKGROUND: A prevalence survey of blindness and low vision was conducted in Oman in 2005. Here, we present the prevalence and determinants of blindness and low vision among the population >or= 40 years of age. The results are then compared with those of the survey in 1997 and the changes following the 'VISION 2020' initiatives are assessed. METHODS: The survey covered 24 randomly selected clusters (75 houses in each). Teams assessed the distance vision of subjects while wearing glasses. The ophthalmologists examined the anterior segment and fundus to determine the causes of disability. The visual field was tested in those suspected of glaucoma. The prevalence rates of blindness (< 3/60 on presentation), legal blindness (< 6/60) and low vision (< 6/18) were calculated. The data from the 1997 survey was then analyzed to obtain similar rates in the population >or= 40 years of age. RESULTS: The prevalence of blindness was 8.25% (95% CI 7.14-9.36) in the >or= 40 year-old population in 2005. The rate would be 6.95% (95% CI 5.92-7.98) if blindness were defined as vision with best possible correction. The prevalence of legal blindness and low vision were 12% and 45.12%, respectively. In the 1997 survey, the prevalence of blindness in same age group was 7.23% (95% CI 5.91-8.55). Between the two surveys, the prevalence of blindness due to corneal pathology declined from 1.9% to 1.1% but that of blindness due to unoperated cataract increased from 1.8% to 2.3%. CONCLUSIONS: The rate of disability has declined but the number of blind people has increased in Oman. The causes of blindness have changed from communicable/avoidable eye diseases to non-curable/chronic eye diseases, and the number with visual disabilities has increased. An increasing number of operations for cataract and improvements in the care for glaucoma and diabetic retinopathy are recommended.