Objective: A prospective study design was used to investigate the association between different degrees of fundus pigmentation and the indicence of retinopathy of prematurity (ROP) among very low birth weight infants in a large neonatal intensive care unit.
Methods: The study group consisted of 161 infants weighing 1500 g or less at birth and included all infants born from 1988 to 1990 who survived at least 10 weeks. Presence or lack of any acute stage ROP was determined by weekly ophthalmological examination from the age of 4 weeks. The degree of fundus pigmentation was recorded for each infant during the first examination.
Results: Infants with dark fundus pigmentation were found to be at half the risk of developing ROP as compared with infants having light/medium fundus pigmentation (relative risk = 0.5; 95% confidence interval = 0.2-1.1). When controlled for birth weight, gestational age, length of oxygen therapy, and ethnic group in multivariate analysis, dark pigmentation was an independent and statistically significant protective factor (odds ration = 0.09, 95% confidence interval = 0.02-0.06). None of the infants with Stage III ROP or higher had dark pigmentation.
Conclusion: We speculate that large amounts of melanin in the retinal pigment epithelium or choroid may protect the dark-pigmented very low birth weight infant from developing ROP.