title: Early retinal vessel development and iris vessel dilatation as factors in retinopathy of prematurity. Cryotherapy for Retinopathy of Prematurity (CRYO-ROP) Cooperative Group.
abstract: OBJECTIVE
  To determine whether the extent of retinal vessel development present on early screening examinations for retinopathy of prematurity has prognostic value?
  
  
  METHODS
  The prospectively collected data from the Multicenter Trial of Cryotherapy for Retinopathy of Prematurity were used to compare the development of acute retinopathy of prematurity and long-term structural and visual outcomes for eyes with differing extents of retinal vessel development.
  
  
  METHODS
  Study patients had eyes with the following vessel development. In zone I eyes, vessels extended from the disc less than twice the distance from the disc to the macula. In zone II eyes, vessels extended beyond zone I but not to the nasal ora serrata. Transitional eyes had vessels partly in zone I and partly in zone II.
  
  
  RESULTS
  The chance of developing threshold retinopathy of prematurity was inversely related to the early degree of vessel development: 54% for zone I eyes, 25% for transitional eyes, and 8% for zone II eyes. The presence of prominent iris vessels at 34 to 35 weeks of postmenstrual age was associated with increased risk for all three groups; zone I eyes almost always needed treatment (94%). The chance of having an unfavorable anatomic alteration of the posterior fundus, or poor vision at the ages of 1 year and 3 1/2 years, was also inversely related to the degree of early vessel development. Vessel development was an independently important factor even when birth weight, gestational age, and race were considered.
  
  
  CONCLUSIONS
  The degree of early retinal vessel development is a significant predictor of outcome from retinopathy of prematurity. Iris vessel dilatation is an important indication for greater vigilance in following these infants.
authors.affiliation: Department of Ophthalmology, Medical College of Wisconsin, Milwaukee, USA.
authors.forename: J D
authors.initials: JD
authors.lastname: Kivlin
authors.forename: A W
authors.initials: AW
authors.lastname: Biglan
authors.forename: R A
authors.initials: RA
authors.lastname: Gordon
authors.forename: V
authors.initials: V
authors.lastname: Dobson
authors.forename: R A
authors.initials: RA
authors.lastname: Hardy
authors.forename: E A
authors.initials: EA
authors.lastname: Palmer
authors.forename: B
authors.initials: B
authors.lastname: Tung
authors.forename: W
authors.initials: W
authors.lastname: Gilbert
authors.forename: R
authors.initials: R
authors.lastname: Spencer
authors.forename: K P
authors.initials: KP
authors.lastname: Cheng
authors.forename: E
authors.initials: E
authors.lastname: Buckley
mesh_terms: D003452:Cryosurgery; D004108:Dilatation, Pathologic; D005865:Gestational Age; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D007498:Iris / Q000098:blood supply*; D011379:Prognosis; D011446:Prospective Studies; D012044:Regression Analysis; D012171:Retinal Vessels / Q000473:pathology*; D012178:Retinopathy of Prematurity / Q000175:diagnosis* / Q000209:etiology / Q000601:surgery; D012307:Risk Factors