The Evolving Concept of Amblyopia: A Challenge to Epidemiologists

Since the end of World War II, the gen-eral public and the scientific community have shown increased interest in the common ophthalmologic condition var-iously known as amblyopia, amblyopia ex anopsia, and "lazy eye. " The child with a patch over one eye has become a common sight, the subject has developed into a fa-vorite research target for neurophysiolo-gists and neuroanatomists (1), and ex-citing new insights have been gained into the underlying disease process (2-6). Re-search progress has been uneven, how-ever. Amblyopia has not attracted much attention from trained epidemiologists, and fundamental epidemiologic questions remain unanswered. The term "amblyopia " simply means dimness of vision and is used for any non-specific loss of visual acuity. Formal def-initions in the literature reflect this gen-erality (7, 8). The term is also used to de-note a specific clinical entity that is easy to illustrate but hard to define. Except where otherwise noted, we will use the term to mean low vision that occurs in infants or young children who have ex-