FOR DECADES, conscientious parents have attempted to provide a bit of light in the rooms of their children to facilitate walking about without injuring toes and to reassure older children that no alien beings have joined them in the room. In the May 13, 1999, issue of Nature, a group from the University of Pennsylvania raised the alarm that the use of a night light in the rooms of infants may be a factor in the development of a myopic refractive error.1 Because of the limited understanding of the etiology of myopia, and some suggestion that eye growth in chicks is influenced by light exposure, Quinn et al1 considered that the amount of light exposure before a child has reached age 2 years, when the eye is undergoing rapid growth, might influence the ultimate length of the eye and thus the refractive error. In their analysis of 479 questionnaires completed by the parents of children aged 2 to 16 years, with eyes not having amblyopia, cataract, glaucoma, or retinopathy of prematurity, who were seen in a university pediatric ophthalmology clinic, the authors report that the prevalence of myopia at the time of the examinations (median age, 8 years) was 10% in the children sleeping in darkness, 34% in children sleeping with a night light, and 55% in children sleeping with the room lights turned on.
Appen RE, Mares-Perlman J. Are the Sky and Night Lights Falling?. Arch Ophthalmol. 2000;118(5):701-702. doi:10.1001/archopht.118.5.701