The Problem Preventable blindness and vision impairment. Worldwide, 39 million people live with blindness, and another 246 million are visually impaired. Yet four out of five cases of blindness are preventable. Further, avoidable vision impairment disproportionately affects the global poor. Around 90 percent of those affected live in the developing world, where a combination of malnutrition, poor water quality, lack of sanitation and inadequate healthcare and health education conspires to spread diseases which damage vision and impede access to treatment. Visual impairment further entrenches people in 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 due to the inability of their impoverished families to care for them.