• Cornea/External Disease

    This is the first detailed, population-based study to describe the types of corneal diseases and the resulting visual impairments in a rural North Indian population. 

    Study design

    The Corneal Opacity Rural Epidemiological study recruited 12,899 participants of all ages in rural North India through house-to-house visits. The prevalence and determinants of corneal opacities, etiologies and the resulting visual impairment were defined according to the WHO guidelines. Visual impairment was defined as presenting VA of 6/18 or less in the better eye and blindness was described as presenting VA of 3/60 or less.


    The prevalence of corneal opacity was 3.7%; 10% of these had severe visual impairment while 50% had normal visual acuity or mild impairment. Approximately 20% of opacities were nebular, 46% were macular, 28% were leucomatous and 5% were adherent leucoma. The risk of having visual impairment was 4 times higher with illiteracy and 11 times higher in individuals 60 years or older.


    The study was conducted exclusively in a rural population and did not ascertain the longitudinal impact of the corneal opacities.

    Clinical significance

    Most of the etiologies of corneal opacities that cause significant ocular morbidity were avoidable. Etiologies such as nutritional deficiencies and iatrogenic corneal opacities could be managed with better eye care and better cataract surgery practices. Causes that were less preventable, such as infection and trauma, were deemed treatable with keratoplasty.