This cross-sectional study investigated the relationship between different lighting conditions experienced during sleep in the first -two years of life and development of myopia after age two as reported retrospectively by parents in a total of 469 individuals, including 252 children aged 2-16 yr., and 217 adults aged 17-40 yr. There were no significant differences in incidence of myopia in children who had slept from 0-2 yr. in darkness, with a night light, room light, or hall light. Adults who were reported by their parents to have slept with a night light on from 0-2 yr. were significantly more likely to be myopic than those who were reported to have slept from 0-2 yr. in any other lighting condition.