Abstract
Purpose: :
To investigate age-related changes in rod photoreceptor and postreceptor function in former preterms with and without a history of ROP.
Methods: :
Following a cross-sectional design, ERG responses to full-field stimuli were recorded from 65 subjects with a history of preterm birth. Subjects were tested as infants (age at test 2 to 8 months post term; n = 36) or at older ages (5 to 23 years; n = 29). Subjects were categorized by maximum severity of acute-phase ROP: mild ROP that regressed spontaneously (n = 38), severe ROP that required treatment (n = 10), or no ROP (n = 17). After 30 minutes of dark-adaptation, responses to a > 4 log unit range of blue flashes were recorded. Rod photoreceptor sensitivity (SROD) and saturated amplitude (RROD) were derived from the a-wave, and postreceptor sensitivity (log σ) and saturated amplitude (VMAX) were calculated from the b-wave stimulus-response function. Each ERG parameter was compared to normal for age. A 2x3 ANOVA was used to evaluate effects of age (younger, older) and ROP severity (mild, severe, no ROP) on ERG response parameters.
Results: :
In both age groups, ~75% of those with a history of any ROP had sensitivity (SROD; log σ) and amplitude (RROD; VMAX) parameters below the 50th percentile of normal for age. Effects of age and ROP severity on SROD and log σ were significant (p < .01). An interaction between age and ROP severity for log σ (p < .03) indicated that in those with severe ROP, postreceptor sensitivity was relatively lower in the older than in the younger group. The effect of age on the amplitude parameters (RROD; VMAX) was consistent with a developmental increment (p < .01). In both age groups, amplitude parameters were smallest in those with severe ROP. Data from subjects in the no ROP group were similar to those in term born controls.
Conclusions: :
Mild but significant deficits in rod and rod-driven retinal activity are common in ROP. Older subjects with a history of severe ROP may be at risk for progressive compromise of neural retinal function.
Keywords: retinopathy of prematurity • electroretinography: non-clinical • retina