title: Astigmatism in the Early Treatment for Retinopathy Of Prematurity Study: findings to 3 years of age.
abstract: OBJECTIVE
  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.
  
  
  METHODS
  Randomized, controlled clinical trial.
  
  
  METHODS
  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.
  
  
  METHODS
  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.
  
  
  METHODS
  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.
  
  
  BACKGROUND
  The author(s) have no proprietary or commercial interest in any materials discussed in this article.
authors.affiliation: Department of Ophthalmology, Cardinal Glennon Children's Medical Center, Saint Louis University School of Medicine, St. Louis, Missouri 63104, USA. davittb@slu.edu
authors.forename: Bradley V
authors.initials: BV
authors.lastname: Davitt
authors.forename: Velma
authors.initials: V
authors.lastname: Dobson
authors.forename: Graham E
authors.initials: GE
authors.lastname: Quinn
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Hardy
authors.forename: Betty
authors.initials: B
authors.lastname: Tung
authors.forename: William V
authors.initials: WV
authors.lastname: Good
mesh_terms: D000367:Age Factors; D001251:Astigmatism / Q000453:epidemiology / Q000209:etiology* / Q000503:physiopathology; D002675:Child, Preschool; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D007234:Infant, Premature; D019102:Infant, Very Low Birth Weight; D017075:Laser Coagulation; D011183:Postoperative Complications; D015995:Prevalence; D012178:Retinopathy of Prematurity / Q000503:physiopathology / Q000601:surgery*; D042262:Retinoscopy; D013997:Time Factors