Light and the developing retina
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Retinopathy of prematurity (ROP) has increased in the United States in the past decade. Its resurgence has been attributed to advances in medical care which have increased the survival of infants less than 1000g. Retinal immaturity and exposure to supplementary oxygen are generally accepted as the principal factors associated with ROP, however precocious exposure of the immature retina to light may also contribute. The preterm infant is routinely exposed for the duration of hospital stay to bright continuous light at levels which produce retinal damage in animals. A recent study has provided evidence implicating light in ROP. Preterm infants for whom the light levels were reduced had a lower incidence of ROP, compared to a similar group of preterms exposed to standard levels of nursery light. Given the problems of a non-randomized design, the results must be considered preliminary; however the findings are substantiated by parallel results in both hospitals studied and by an effect of exposure to light within the treatment group. Speculations regarding the mechanisms of light as a contributor to ROP include: alterations of retinal metabolism, cellular damage by phototoxicity, and the generation of free radicals. Mechanisms of phototoxicity are compatible with theories of oxygen toxicity. Light may not be necessary for ROP to occur, but it may increase the risk.
Key wordsretinopathy of prematurity light phototoxicity oxygen
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- 2.Gaiter J, Avery GB, Temple C, Johnson A, White N. Stimulation characteristics of nursery environments for critically ill preterm infants and infant behavior. In Stern D (ed): ‘Intensive Care in the Newborn, 3rd Ed.’ New York, Masson Publishing Co., 1981; pp 389–410.Google Scholar
- 7.Abramov I, Hainline L, Lemerise E, Brown AK. Changes in visual functions of children exposed as infants to prolonged illumination. J Am Optometry Assoc 1985; 56: 614–619.Google Scholar
- 12.Williams T, Baker B (eds). Symposium on Effects of Constant Light on Visual Processes. New York: Plenum Press, 1980.Google Scholar
- 21.Locke JC, Reese AB. Retrolental fibroplasia. Arch Ophthalmol 1952; 48: 44–47.Google Scholar
- 23.Glass P. Role of light toxicity in the developing retinal vasculature. Birth Defects. Vol. 24, No. 1, 103–117.Google Scholar
- 26.Flower RW, McLeod DS, Lutty GA. Postnatal retinal vascular development of the puppy. Invest Ophthal and Visual Sci 1984; 26: 957–968.Google Scholar