A population-based study on the prevalence and causes of childhood blindness and visual impairment in North India.

PURPOSE: This was a population-based study to determine the prevalence and causes of visual impairment in children less than 16 years in Urban North India.

METHODS

This cross-sectional study was conducted in 40 clusters of urban Delhi. 20,955 children aged less than 16 years underwent visual acuity screening using age-appropriate visual acuity charts. Unaided visual acuity of enumerated children aged over 2 years was assessed by using Lea symbols chart in 3-5 years age group and logMAR tumbling E charts for the 6-15 years age group. For children aged 0-2 years, fixation and following to torch light was assessed. All the children with unaided visual acuity of <6/12 in any eye in age group 3-15 years and inability to follow the light in age <3 years were referred for detailed ophthalmic examination.

RESULTS

Amongst 20,955 children examined for visual acuity a total of 789 children were referred to the central clinic for detailed ophthalmic examination. Of these referred children, a total of 124 had presenting visual acuity <6/18 in the better eye. The prevalence of visual impairment (VI) was 5.92 per thousand (95% CI: 4.96-7.05). The prevalence of moderate to severe visual impairment was maximum in the age group of 11 to 15 years. The main cause of avoidable VI in these children was a refractive error (75.7%). The prevalence of blindness was 0.42 per thousand.

CONCLUSION

Optic nerve abnormalities were the most important cause of blindness in children. Refractive error is the most important cause of visual impairment amongst children and needs to be addressed.