Development of Anisometropic Amblyopia in Children treated for Type I Retinopathy of Prematurity

Abstract

Purpose :
Children with ROP treated with laser tend to have higher incidence of high myopia compared to individuals treated with intravitreal bevacizumab (IVB); however, the incidence of amblyopia and abnormal binocular vision between these two groups has yet to be established. We examined the progression of refractive error and development of anisometropic amblyopia in children treated for ROP with IVB, laser, or IVB followed by laser treatment.

Methods :
We identified premature infants with ROP treated with IVB at Boston Children’s Hospital from 2011-2020 (n =40). We compared cycloplegic refraction and visual acuity data in these individuals to ROP babies treated with laser during the same time frame (n = 48). A subset of individuals treated with IVB also underwent additional treatment with laser (n = 18). We included cycloplegic refraction and visual acuity from 392 cumulative visits (median 3, range 2-13 per individual) over a median of 3.2 (range 0.5-8.5) years. We used a linear mixed effects model to compare risk factors for amblyopia including anisometropic refractive error, astigmatism, and strabismus between groups to determine differences in amblyopia risk and incidence.

Results :
There was a higher incidence of anisometropic amblyopia, as defined by a >0.1 logMAR difference between eyes, in those treated with both IVB and subsequent laser (P = 0.0243). A secondary analysis accounting for differences in ROP characteristics (zone, stage, and number of clock hours of affected retina) and number of laser spots showed ROP zone had a significant effect on anisometropia, with less anisometropia in individuals with zone 2 ROP. There was no effect on incidence of amblyopia. The number of laser spots used for treatment had no significant effect on anisometropia (P = 0.255) or astigmatism.

Conclusions :
Our data provide evidence that a subset of individuals requiring subsequent laser treatment following IVB therapy are more likely to develop anisometropic amblyopia. There was no effect of ROP zone, stage, and area of affected retina on the development of amblyopia in this sample.

This abstract was presented at the 2022 ARVO Annual Meeting, held in Denver, CO, May 1-4, 2022, and virtually.