Collaborating physicians will also refer historical controls, who have not been treated in the first year of life or who received one month or less therapy, and are older than one year. Absence of treatment in the first year of life will be due to parental preference, prior inadequate follow-up by the family physicians, or lack of detection or treatment of eye disease before the age of one year in otherwise asymptomatic children. These historical, untreated patients (who enter the study when they are older than one year) will be compared with treated children in the randomized study. These historical patients will not be randomized. Any abnormality requiring treatment (e.g., active chorioretinitis) in any child (including historical patients) will be treated.