Poor eye health is, surprisingly to many, one of the most common health problems for people in developing countries.
The World Health Organization (WHO) estimates that one adult goes blind every second, and one child becomes blind every minute. Globally, an estimated 314 million people are visually impaired, including 45 million people who are blind – 90 per cent live in low-income countries.
The two biggest causes of visual impairment in developing countries are cataract, a clouding of the lens that stops light reaching the retina, and uncorrected refractive errors, where the eye doesn’t focus images on the retina correctly (leading to blurred vision) and this isn’t adjusted through glasses or contact lenses. Two of the leading five neglected tropical diseases (NTDs) are also significant causes of blindness: trachoma, an infection than can eventually lead to scarring of the cornea, and onchocerciasis (or river blindness), a parasitic disease transmitted by small black flies, both of which are being reduced through effective long-term control programmes. A collection of childhood conditions, including corneal scarring from vitamin A deficiency, are also important causes.