Abstract
Abstract: :
Purpose: Conduct a longitudinal investigation of rod photoreceptor and post–receptoral function in rats with oxygen induced retinopathy ("ROP rats"), a model of human retinopathy of prematurity. Methods: Retinopathy was induced using the oxygen exposures recommended by Penn. Starting at age 16 days, and thereafter at approximately weekly intervals, ERG responses to a 6+ log unit range of full–field stimuli were recorded from dark adapted, lightly anesthetized rats. Rod cell sensitivity (SROD) and saturated response amplitude (RROD) were calculated by fit of a model of the activation of phototransduction to the ERG a–wave. Postreceptoral responses were evaluated by analysis of ERG b–wave stimulus/response functions; saturated b–wave amplitude (Vmax) and b–wave sensitivity (1/σ) were calculated. Results: In ROP rats, SROD and RROD were lower than in controls at all ages, but showed modest developmental increases; the deficits in SROD predict deficits in post receptoral sensitivity. In control rats, both receptoral and post receptoral response parameters showed developmental increases. Conclusions: In contrast to the resolution of the vascular abnormalities (Falk et al.), retinal dysfunction persists long after the ROP inducing exposure, and is present in mature retina just as in children with mild ROP. In ROP rats, as in human ROP subjects, rod function predicts post–receptoral function
Keywords: electroretinography: non–clinical • retinopathy of prematurity • photoreceptors