Purpose: Midgestation is a critical period in the formation of the foveal avascular zone. The authors evaluated the effects of preterm birth on foveal structure in children with regressed retinopathy of prematurity.
Methods: Children with regressed retinopathy of prematurity with normal-appearing posterior poles (n = 26) and full-term control children (n = 56) were investigated. Frequency-domain optical coherence tomography 9-mm line scans across the fovea were obtained from right eyes. Using a customized segmentation program in MATLAB, total retinal thickness and the thickness of individual retinal layer regions were measured at the fovea (0°) and throughout ± 8°.
Results: Total thickness of the fovea in the retinopathy of prematurity group (287.7 ± 47.6 μm) was greater than that in the control group (230.1 ± 18.2 μm). Bilinear fitting was performed to examine the relationship between total thickness and gestational age. Before 28 weeks, foveal thickness decreased with gestational age (14.3 μm/week); after 28 weeks, foveal thickness decreased only slightly (2.73 μm/week). Inner retinal layers contributed to the difference in thickness between groups more than outer layers. Foveal thickness was correlated with gestational age at birth but not with visual acuity or refractive error.
Conclusion: Preterm birth before 28 weeks of gestational age was associated with a failure of the inner retinal layers to migrate away from the fovea, resulting in increased foveal thickness.