Q. What’s the No. 1 cause ofblindness in older adults in the United States?
A. “It sounds like a simple question, but there’s no perfect answer,” said Dr. Susan Vitale, a research epidemiologist at theNational Eye Institute of the National Institutes of Health. “It depends on age, how blindness is measured and how statistics are collected.” For example, some studies have relied on the self-reported answer to the vague question: “Do you have vision problems?”