Prevalence of Myopia Between 6 Months and 3 Years of Age in Children Participating in the Early Treatment of Retinopathy of Prematurity (ETROP) Trial

Abstract

Purpose:: Determine the prevalence of myopia and high myopia, at 6 and 9 months post term and 2 and 3 years postnatal in preterm children with birth weights <1251g who developed high-risk prethreshold retinopathy of prematurity (ROP) in the neonatal period and participated in the Early Treatment for ROP (ETROP) Study.

Methods:: ETROP trial enrolled 401 infants with prethreshold ROP in one or both eyes and were determined to have ≥15% risk of poor structural outcomes without treatment, using the RM-ROP2 risk management program. Eyes were randomized to receive laser photocoagulation at high-risk prethreshold ROP or to be conventionally managed, with treatment occurring only if threshold ROP developed. Children underwent cycloplegic retinoscopy at 6 and 9 months corrected age and at 2 and 3 years old. Excluded were eyes with vitrectomy, scleral buckling, iridectomy or eyes with glaucoma or cataract surgery.

Results:: Prevalence of myopia (sph eq ≥0.25 D) was similar in eyes that underwent treatment when they developed high-risk prethreshold ROP, compared to eyes with high-risk prethreshold disease that were managed conventionally, showing an increase from approximately 58% to 68% between 6 and 9 months, with little change thereafter to age 3 years. Both early treated and conventionally managed eyes showed an increasing prevalence of high myopia (≥5.00 D), beginning at approximately 19% at 6 months and increasing 4% to 8% at each successive examination. Zone of acute-phase ROP and the presence or absence of plus disease had little effect on prevalence of myopia or high myopia between ages 6 months and 3 years. However, eyes with retinal residua of ROP (straightened temporal retinal vessels or macular heterotopia) showed a higher prevalence of myopia and high myopia than did eyes with no retinal residua.

Conclusions:: Timing of treatment of high-risk prethreshold ROP did not influence refractive error development. Although prevalence of myopia increased between 6 and 9 months and remained stable thereafter, prevalence of high myopia increased over time, with most of the increase occurring in eyes with myopia ≥8 D. Presence of myopia and high myopia was related more to severity of retinal residua of ROP than to severity (zone, presence of plus disease) of acute-phase ROP.

Clinical Trial:: www.clinicaltrials.gov NCT00027222

Keywords: retinopathy of prematurity • myopia • refractive error development