Abstract
Abstract: :
Purpose:To prospectively study the relationship between the severity of retinopathy of prematurity (ROP), ocular growth and the develpoment of refractive error in premature babies before three months postmenstrual age. Methods: Premature infants enrolled in the national ROP screening program were recruited and examined at 32, 36, 40, 44 and 52 weeks' postmenstrual age. Refractive error (RE) was measured with routine cycloplegic refraction. Axial length (AXL), anterior chamber depth (ACD), and lens thickness (LT), were measured on the A–scan biometer. Corneal curvature (CC) was measured using a video–ophthalmophakometer, and stage of retinopathy was recorded according to the International Classification of Retinopathy of Prematurity. Multilevel modelling techniques were used to determine the relationships between all the variables throughout the study period. Results: 136 babies were studied; 67 were unaffected by ROP, 19 developed stage 1, 26 developed stage 2, 12 developed stage 3, and 12 developed threshold disease that required laser treatment. Gestational age (GA) and birth weight (BW) were significantly greater in the stage 0 group compared to all others. As the severity of ROP increased, AXL and ACD decreased. LT showed no significant change over this study period. CC was significantly greater in the babies who developed threshold disease, although the growth rates were similar for all stages of ROP. As stage of ROP incresed, rate of change of RE decreased, such that the group with threshold disease developed the least hyperopia. When the effects of GA and BW were accounted for, differences noted between stages of ROP were reduced, but not totally negated. Conclusions: As the severity of ROP increased, AXL and ACD reduced, and CC increased, resulting in a trend towards less hyperopia. GA and BW had confounding effects on RE and ocular growth, but did not explain all the differences shown. Even during this early period of ocular development, ROP could be seen to be exerting an effect.
Keywords: retinopathy of prematurity • refractive error development