Eye size in threshold retinopathy of prematurity, based on a Danish preterm infant series: early axial eye growth, pre- and postnatal aspects

To validate a hypothesis of restricted postnatal ocular growth associated with advanced retinopathy of prematurity (ROP), with a view also to preceding intrauterine growth retardation. A clinically uniform sample of 28 preterm neonates was examined under general anesthesia from 1997 to 2002 for threshold retinopathy of prematurity (T-ROP), axial ultrasound oculometry being part of the evaluation (valid data in 53 eyes). Median values for gestational age at delivery (GA) and birth weight (BW) 27 weeks and 855 g, respectively, ranges 24.7-30.9 weeks and 480-1594 g. Median postconceptional age (PCA) at exam was 36.2 weeks (32.2-41.4 weeks) and median postnatal age was 9 weeks (5.8-14 weeks). "Small for gestational age" (SGA) at delivery was given by an individual birth weight standard deviation score. Compared with a previous Danish preterm series with less ROP, age-adjusted axial lengths (AL) in the T-ROP eyes were roughly 1 mm shorter and anterior chambers shallower. A higher GA was found to coincide with lower AL values; this appeared due to a subpopulation of infants loaded by SGA. The literature has no other uniform oculometry series of preterms of a similar advanced ROP degree. The present Danish results add to the composite picture drawn by neonatal reports from other investigators. There is evidence of postnatal ocular growth restriction in preterms associated with severe ROP. Some kind of latency is probable, from the immediate delivery-related biological effects until the appearance of macroscopic evidence. Statistics further suggested SGA as an apparently independent prenatal predictor of subsequent ocular growth restriction.