RT Journal Article SR Electronic T1 Myopia, genetics, and ambient lighting at night in a UK sample JF British Journal of Ophthalmology JO Br J Ophthalmol FD BMJ Publishing Group Ltd. SP 580 OP 582 DO 10.1136/bjo.87.5.580 VO 87 IS 5 A1 J A Guggenheim A1 C Hill A1 T-F Yam YR 2003 UL http://bjo.bmj.com/content/87/5/580.abstract AB Background: It has been reported that exposure to artificial lighting at night during the first 2 years of life was very strongly associated with subsequent myopia development. Methods: The strength of this association was tested in a UK sample for the first time. The study population comprised 122 university students. Results: Myopia occurred with approximately equal frequency in those who slept with and without light exposure at night. In contrast, two largely genetic factors, parental myopia and race, were both significantly associated with myopia development, as has been found previously. Conclusion: This study provides further support for the view that night-time light exposure during infancy is not a major risk factor for myopia development in most population groups. In a subset of this cohort for which spectacle prescriptions were available for both parents (49 trios), the heritability of ocular refraction was estimated to be 0.31.