Astigmatism in the Early Treatment for Retinopathy Of Prematurity Study: findings to 3 years of age

Abstract

Purpose: To examine the prevalence of astigmatism (> or =1.00 diopter [D]) and high astigmatism (> or =2.00 D) at 6 and 9 months corrected age and 2 and 3 years postnatal age, in preterm children with birth weight of less than 1251 g in whom high-risk prethreshold retinopathy of prematurity (ROP) developed and who participated in the Early Treatment for Retinopathy of Prematurity (ETROP) Study.

Design: Randomized, controlled clinical trial.

Participants: Four hundred one infants in whom prethreshold ROP developed in one or both eyes and who were randomized after they were determined to have a high risk (> or =15%) of poor structural outcome without treatment using the Risk Management of Retinopathy of Prematurity (RM-ROP2) program. Refractive error was measured by cycloplegic retinoscopy. Eyes with additional retinal, glaucoma, or cataract surgery were excluded.

Intervention: Eyes were randomized to receive laser photocoagulation at high-risk prethreshold ROP (early treated [ET]) or to be conventionally managed (CM), receiving treatment only if threshold ROP developed.

Main outcome measures: Astigmatism and high astigmatism at each visit. Astigmatism was classified as with-the-rule (WTR; 75 degrees -105 degrees ), against-the-rule (ATR; 0 degrees -15 degrees and 165 degrees -180 degrees ), or oblique (OBL; 16 degrees -74 degrees and 106 degrees -164 degrees ).

Results: The prevalence of astigmatism in ET and CM eyes was similar at each test age. For both groups, there was an increase in prevalence of astigmatism from approximately 32% at 6 months to approximately 42% by 3 years, mostly occurring between 6 and 9 months. Among eyes that could be refracted, astigmatism was not influenced by zone of acute-phase ROP, presence of plus disease, or retinal residua of ROP. Eyes with astigmatism and high astigmatism most often had WTR astigmatism.

Conclusions: By age 3 years, nearly 43% of eyes treated at high-risk prethreshold ROP developed astigmatism of > or =1.00 D and nearly 20% had astigmatism of > or =2.00 D. Presence of astigmatism was not influenced by timing of treatment of acute-phase ROP or by characteristics of acute-phase or cicatricial ROP. These findings reinforce the need for follow-up eye examinations in infants with high-risk prethreshold ROP.

Financial disclosure(s): The author(s) have no proprietary or commercial interest in any materials discussed in this article.

Figure 1

Prevalence of astigmatism (≥ 1.00 diopter (D), Figures 1A and 1B) and high astigmatism (≥ 2.00 D, Figures 1C and 1D) at 6 and 9 months corrected and at 2 and 3 years postnatal age as related to location (zone) of the most severe acute-phase ROP in each eye. Numbers above each bar indicate the number of eyes that provided data at each age.

Figure 2

Prevalence of astigmatism (≥ 1.00 diopter (D), Figures 2A and 2B) and high astigmatism (≥ 2.00 D, Figures 2C and 2D) at 6 and 9 months corrected and at 2 and 3 years postnatal age as related as related to the presence or absence of plus disease at the time of the most severe acute-phase ROP in each eye. Numbers above each bar indicate the number of eyes that provided data at each age.

Figure 3

Distribution of astigmatic refractive errors at four ages in (A) eyes treated at high-risk prethreshold ROP, and (B) eyes with high-risk prethreshold ROP that were managed conventionally.

Figure 4

Prevalence of astigmatism (≥ 1.00 diopter (D), Figures 4A, 4B and 4C) and high astigmatism (≥ 2.00 D, Figures 4D, 4F, and 4G) at 6 and 9 months corrected and at 2 and 3 years postnatal age as related to severity of retinal residua of ROP in each eye. Black bars indicate prevalence in eyes that underwent treatment at high risk prethreshold ROP; gray bars indicate prevalence in eyes with high risk prethreshold ROP that were managed conventionally. Numbers above each bar indicate the number of eyes that provided data at each age.

Figure 5

Axis of astigmatism in eyes with any astigmatism (≥ 1.00 diopter (D), Figure 5A) and in eyes with high astigmatism (≥ 2.00 D, Figure 5B) at 6 and 9 months corrected and at 2 and 3 years postnatal age. Numbers above each bar indicate the number of eyes that provided data at each age. Early Treatment (ET); Conventional Management (CM)