Abstract
Abstract: :
Purpose:In former preterms with Mild ROP, determine the developmental course of rod mediated visual thresholds in peripheral and late maturing parafoveal retina. Rod cell involvement has been documented in animal models of ROP and, by electroretinography, in children with ROP. Methods:We used preferential looking in conjunction with a staircase procedure to estimate dark adapted, scotopic visual thresholds for detecting 2° diam, 50 ms duration spots presented at peripheral (30° eccentric) and parafoveal (10° eccentric) retinal sites. Every subject was tested at both sites. Starting at age 10 weeks post term, 12 former preterms (GA 24 to 31 weeks; BW 640 to 2000g), 6 with a history of Mild ROP, 6 with No ROP, were tested longitudinally until at least age 6 months, the age at which term born infants (n=9) have both 10° and 30° thresholds equal to those of adults (Hansen & Fulton, 1999). Results:At age 10 weeks, the troland value and variability of thresholds at both retinal sites did not differ significantly among Mild ROP, No ROP, and term born infants. By age 6 months, the peripheral threshold in Mild ROP, No ROP and term born infants was also indistinguishable. However, at age 6 months every ROP subject had a parafoveal threshold above (sensitivity below) that of any term born infant. Furthermore, the rate at which the parafoveal threshold decreased in ROP was significantly more variable than normal. Conclusion:Mild ROP disturbs the course of maturation of parafoveal retina. Photon capture by parafoveal rod outer segments may be inefficient in Mild ROP.
Keywords: 572 retinopathy of prematurity • 623 visual development: infancy and childhood • 518 photoreceptors: visual performance