In this masked, controlled study, infants weighing less than 1,251 grams at birth were prospectively randomized within 24 hours of birth to wear goggles or not to wear goggles. Goggles contain 97 percent near neutral density filters and were worn until the infant reached either 31 weeks gestational age or 4 weeks postnatal age, whichever was longer. The goggled and nongoggled infants were exposed to the same ambient light conditions within any given Study Center. Eyes of all infants were examined on a prescribed schedule by certified examiners to determine the incidence of any confirmed ROP.