Abstract
Purpose :
To investigate the development of rod-mediated dark-adapted thresholds (DATs) at 10° and 30° eccentricities in children with a history of retinopathy of prematurity (ROP) treated by ablation of the peripheral avascular retina.
Methods :
To date, 144 subjects have contributed one or more DATs. Age at test ranged from 10 weeks post-term through adulthood. Sixteen subjects had ROP that required ablative therapy (Severe). The remaining preterm subjects are stratified into two groups: 32 who never developed ROP (None) and 68 who had ROP that resolved without treatment (Mild). Twenty-eight term-born subjects serve as controls (Term). An additional 3 subjects who were treated for severe ROP using anti-VEGF (bevacizumab) therapy are presented for comparison. Thresholds for detection of 2° diameter, 50 ms, blue spots, at both 10° and 30°, were estimated using a two-alternative, forced-choice, transformed up-down staircase. To quantify the developmental timecourse for each group, thresholds are expressed as the proportion of adult normal for corrected age; the group data at each eccentricity are then fit to logistic growth curves with asymptote 1, exponent shared across group and eccentricity, and age-at-half-maximum free to vary. The curves are then evaluated for significant differences. To determine the relative determinants of DAT of group (Severe, Mild, None), birth weight (BW), and gestational age at birth (GA), each threshold is re-expressed as the respective delta from the normal 10° threshold for age and fit by a fixed effects linear model with these three aforementioned factors.
Results :
In ROP (Severe, Mild) DAT development at 10° is significantly (P<0.01) delayed compared with normal (None, Term); the Severe and Mild groups are statistically indistinguishable. Normal DAT development is only minimally delayed at 10° relative to 30°, and at 30° there are no significant intergroup differences. In the linear model, ROP severity is a significant determinant of DAT, but BW and GA are not. Notably, at both retinal eccentricities, sensitivity in those treated with anti-VEGF exceeds sensitivity in the other groups.
Conclusions :
At 10°, ROP—whether Mild or Severe (and treated with ablative therapy)—is associated with significant delays in DAT development. This result adds to the accumulating evidence that the late-maturing central (i.e., 10°) retinal rods are particularly vulnerable to ROP.
This is a 2020 ARVO Annual Meeting abstract.