Abstract
Abstract: :
Purpose: Study cone cell function in children with retinopathy of prematurity (ROP). Rod cells are involved in the ROP disease process (Fulton et al, Arch Ophthalmol, 119:499, 2001), but cone function has yet to be studied. Methods: ERG responses to a range of red full– field flashes (0.6 to +2.6 log phot td sec) on a rod saturating white background were recorded from infants and children with a history of mild ROP (N=10), and preterm birth but no ROP (N=5). Cone cell sensitivity (SCONE) and saturated amplitude (RCONE) were calculated by fit of a model of the activation of phototransduction to the ERG a–wave. In a similar fashion, rod cell sensitivity (SROD) and saturated amplitude (RROD) were studied in each subject. Photoresponse parameters were expressed as percent of normal for age, and also compared to the 95% prediction interval of normal for age. Results: Every ROP subject had SCONE within the 95% PI for normal. Values of SCONE were distributed about the normal mean for age, and were, on average, 89% (SD= 32%). On the other hand, SROD was below the normal mean in all but one subject (Average 76%; SD=24% of normal for age), although only one had SROD below the 95% prediction limit. The cone and rod response parameters of preterm subjects with no ROP were indistinguishable from normal. Conclusions: Cone cell function of children with a history of mild ROP is only minimally altered even if rod function is compromised. Thus the cones, which are relatively more mature than rods at ages when ROP is active (Hansen & Fulton, ARVO, 2000), may be less involved in the ROP disease process.
Keywords: retinopathy of prematurity • visual development: infancy and childhood • photoreceptors