Cataract indicators: their development and use over the last 30 years

COMMUNITY EYE HEALTH JOURNAL | VOLUME 30 | NUMBER 100 | 2017 For the last four to five decades, cataract has been the most common cause of blindness worldwide; it is also a leading cause of visual impairment. Before this, fewer people grew old enough to develop cataract and infectious diseases (trachoma, onchocerciasis, measles) were thought to cause most blindness. Thanks to improved hygiene, antibiotics, ivermectin, vaccinations and vitamin A distribution, eye infections and xerophthalmia have become less common. At the same time, life expectancy increased, leading to a rapid increase in the incidence (i.e. new cases) of cataract. Because the incidence of cataract increases exponentially with increasing age, the age composition of the population determines the number of new cases of cataract; i.e., countries with older populations tend to have more people with cataract.