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Retinopathy of prematurity: A systematic review of the literature.

OBJECTIVE
To assist in the diagnosis of retinopathy of prematurity (ROP) to facilitate treatment in a timely manner to help prevent blindness.


DATA SOURCES
Systematic review using MEDLINE including the following key words, "retinopathy of prematurity", "retrolental fibroplasia", "blind", "blindness", "vision screening", "cryotherapy", "cryosurgery", "laser" and "ablative therapy". The bibliographies of the references found using the above techniques were scanned for references missed in the primary search.


DATA SELECTION
Eight population-based studies examining the incidence and severity of ROP were identified. Other studies of ROP were included because they contributed to an understanding of the natural history, treatment or long term outcome of ROP.


DATA EXTRACTION
Data was analyzed cumulatively from the population-based studies to determine the incidence of ROP. For the natural history, treatment and schedule of eye examinations, data was reported from individual studies.


DATA SYNTHESIS
Infants at greatest risk of ROP were 1500 g or less at birth, or 30 weeks gestational age or younger. An inverse relationship existed between the incidence and severity of ROP and birth weight or gestational age. The age of onset of ROP was four to six weeks; however, a few newborns presented with an aggressive form of ROP called 'rush disease' as early as three weeks of age. For those requiring treatment for ROP, the maximum severity was about 11 weeks of age. Long term follow-up for refractive errors was more effective between six and 12 months and again at four years.


CONCLUSION
Very premature or very low birth weight infants are at highest risk of ROP. Based upon published information, an optimal screening schedule is recommended and a long term follow-up strategy is provided.