title: Evidence-based screening criteria for retinopathy of prematurity: natural history data from the CRYO-ROP and LIGHT-ROP studies.
abstract: BACKGROUND
  The Multicenter Trial of Cryotherapy for Retinopathy of Prematurity (CRYO-ROP) demonstrated the efficacy of treatment for threshold ROP and indicated the need for worldwide ROP screening. Previous guidelines for ROP screening have been largely based on clinical impression; we can now develop evidence-based screening recommendations.
  
  
  OBJECTIVE
  To define the appropriate ages and retinal ophthalmoscopic signs that determine when to commence and conclude acute phase ROP screening.
  
  
  METHODS
  Analysis of data from 2 prospective randomized controlled trials: CRYO-ROP (January 1, 1986, to November 30, 1987) and Light Reduction in ROP (LIGHT-ROP) (July 1, 1995, to March 31, 1997).
  
  
  METHODS
  Neonatal intensive care units in 23 study centers in the United States for CRYO-ROP and 3 centers for LIGHT-ROP.
  
  
  METHODS
  Eyes were examined sequentially in 4099 infants with birth weight less than 1251 g (CRYO-ROP study) and in 361 infants with birth weight less than 1251 g and gestational age less than 31 weeks (LIGHT-ROP study).
  
  
  RESULTS
  In 99% of infants, retinal conditions indicating a risk of poor outcome were not observed before 31 weeks' postmenstrual age or 4 weeks' chronologic age. Signs indicating that the risk of visual loss from ROP was minimal or had passed were the infant's attainment of 45 weeks' postmenstrual age without the development of prethreshold ROP or worse, progression of retinal vascularization into zone III without previous zone II ROP, and full vascularization.
  
  
  CONCLUSIONS
  The initial eye examination should be conducted by 31 weeks' postmenstrual age or 4 weeks' chronologic age, whichever is later. Acute phase ROP screening can be discontinued when any of the 3 signs is present, indicating that the risk of visual loss from ROP is minimal or passed.
authors.affiliation: Department of Ophthalmology, University at Buffalo, 219 Bryant St, Buffalo, NY 14222, USA.
authors.forename: James D
authors.initials: JD
authors.lastname: Reynolds
authors.forename: Velma
authors.initials: V
authors.lastname: Dobson
authors.forename: Graham E
authors.initials: GE
authors.lastname: Quinn
authors.forename: Alistair R
authors.initials: AR
authors.lastname: Fielder
authors.forename: Earl A
authors.initials: EA
authors.lastname: Palmer
authors.forename: Richard A
authors.initials: RA
authors.lastname: Saunders
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Hardy
authors.forename: Dale L
authors.initials: DL
authors.lastname: Phelps
authors.forename: John D
authors.initials: JD
authors.lastname: Baker
authors.forename: Michael T
authors.initials: MT
authors.lastname: Trese
authors.forename: David
authors.initials: D
authors.lastname: Schaffer
authors.forename: Betty
authors.initials: B
authors.lastname: Tung
mesh_terms: D000367:Age Factors; D003452:Cryosurgery; D019317:Evidence-Based Medicine; D005865:Gestational Age; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008028:Light Coagulation; D015337:Multicenter Studies as Topic; D009887:Ophthalmoscopy; D017410:Practice Guidelines as Topic / Q000592:standards*; D011446:Prospective Studies; D016032:Randomized Controlled Trials as Topic; D012178:Retinopathy of Prematurity / Q000175:diagnosis* / Q000601:surgery; D012307:Risk Factors; D013997:Time Factors