Abstract
Purpose: :
Study rod–mediated visual development in infants with and without a history of ROP. Young infants with a history of ROP are known to have deficits in rod function. To characterize subsequent development, we conducted a study of the maturation of visual thresholds in ROP subjects.
Methods: :
Longitudinal measures of dark–adapted visual thresholds for detecting stimuli (2o diameter, 50 ms duration) presented at 10o (parafoveal) and 30o (peripheral) eccentric sites were obtained using a two–alternative, forced–choice, preferential–looking method. Twenty–three former preterms (GA: 24 to 31 weeks) were tested; 16 had a history of ROP and 7 never had ROP. The course of threshold development in ROP subjects was compared to that of term born infants.
Results: :
In subjects who had ROP, the course of threshold development was delayed at both parafoveal and peripheral sites. Thresholds did not reach adults’ values until 10 (6 to 15) months at the peripheral site and 13 (7 to 18) months at the later maturing parafoveal site, whereas in term born controls, thresholds reached adults’ values by age 6 months. In former preterm infants with no history of ROP, the course of threshold development was indistinguishable from that in term born controls.
Conclusions: :
The prolonged course of maturation of rod–mediated thresholds, which is more marked in the later maturing parafoveal retina, is evidence that ROP alters the development of the rods and neural retina.
Keywords: infant vision • retinopathy of prematurity • visual development: infancy and childhood