Causes of childhood blindness changing

Chicago-The patterns of childhood blindness and visual impairment are changing over time, according to Clare Gilbert, MD, MSc. Dr. Gilbert described the shifts in pediatric blindness patterns resulting from the “nurture” factors Sunday at the American Academy of Ophthalmology annual meeting.

“The prevalence of pediatric eye disease is impacted heavily by the environment, cultural patterns, and socioeconomic status and is very closely associated with the mortality rates in children under 5 years,” she said, with approximately 1.4 million children blind worldwide, mostly in developing countries. The conditions that exist in those countries are vitamin A deficiency, malaria, inadequately controlled diseases such as measles, inadequate services, and lack of education.

Childhood blindness rates vary greatly by economic status. In affluent countries, for example, the prevalence of childhood blindness is 0.3/1,000 children; in a population of 10 million, this translates into about 600 children who are blind. This is in contrast to very poor countries that have a prevalence of childhood blindness of 1.2/1,000, which in a population of 10 million is responsible for 6,000 blind children.

The causes of blindness also differ in these populations, with 0% of cases from corneal scarring, 10% from retinopathy of prematurity (ROP), and 80% from other causes in affluent populations; in very poor communities, however, 50% of cases of blindness result from corneal scarring, 15% from cataract and glaucoma, 0% from ROP, and 35% from other causes, according to Dr. Gilbert from the International Centre for Eye Health. London School of Hygiene and Tropical Medicine, London.

“Twenty years ago, the causes of childhood blindness were very different. The rates of corneal scarring were much higher and were associated with higher mortality rates; the rates of corneal scarring are now declining. Programs are now in place to address vitamin A deficiency and measles. ROP also was much less common,” she pointed out.

In the future, she predicted, the incidence of corneal scarring will decrease in Asia with improving economies, there will be better control of vitamin A deficiency and measles, and a decline in blindness resulting from cataract. There will be an increase in blindness from ROP in middle income countries and in Asia and an increase in visual impairment from uncorrected refractive errors.