Prevalence and causes of monocular childhood blindness in a rural population in southern India

Purpose: To determine the prevalence and etiology of childhood monocular blindness in a rural population in southern India.

Methods: A total of 14,423 children younger than 15 years in randomly selected villages (8,222 households) with a total population of 40,336 were screened. Screening was performed in two stages. In the first stage, all children with visual acuity worse than 6/18 in at least one eye were screened. Subsequently, children with visual acuity worse than 3/60 in one eye were referred to a tertiary care hospital for further examination for determination of the cause of visual impairment.

Results: The age range of affected children was 1 to 15 years (median age: 12 years). Fifteen children had monocular visual impairment, yielding a prevalence rate of 1.13 in 1,000 children. Refractive error leading to amblyopia was the most common cause of monocular visual impairment, followed by trauma, congenital disorders, and vitamin A deficiency. One case had toxoplasmosis. Approximately one-third of the children were born of a consanguineous marriage (30.06%). The proportion of first-degree consanguinity (46.4%) was higher than that of second-degree (37.5%) or third-degree (16.1%) consanguinity.

Conclusion: The prevalence of childhood monocular blindness was high in the current study, but most causes were preventable or treatable. Improved screening methods (especially for refractive errors), genetic counseling, and therapeutic interventions can reduce the burden of childhood blindness.