The Problem Reversible blindness and visual impairment. Blindness afflicts 39 million people worldwide, and another 246 million are visually impaired. Yet four out of five people who are blind needn’t be--the majority of cases of blindness are avoidable. Additionally, blindness disproportionately affects the global poor. Around 90 percent of those affected with preventable blindness live in the developing world. A combination of malnutrition, poor water quality, lack of sanitation, and inadequate healthcare and health education contributes to diseases that impair vision. Visual impairment can further perpetuate the cycle of poverty and can be deadly for sufferers: over half of children die within a few years of going blind, either from the underlying disease or the inability of their impoverished families to care for them.