Early Treatment for Retinopathy of Prematurity (ETROP) trial

A US trial from the National Eye Institute that asked whether treating retinopathy of prematurity earlier gives better visual and structural results than conventional treatment. In babies with both eyes affected, one eye was treated early and the other managed conventionally. Early treatment lowered the share of unfavourable outcomes at 9 months, and the further analysis led the authors to modify the recommendations for treating eyes with ROP.

Study
In this atlas

Overview

Design: Randomised trial in infants with high-risk prethreshold ROP. Bilateral cases: one eye randomised to early treatment (ablation of the avascular retina) and the fellow eye managed conventionally. Asymmetric cases: the one eye with high-risk prethreshold ROP randomised to early treatment or conventional management.
Phase: Phase 2/3
Enrolled: 317 infants with bilateral high-risk prethreshold ROP (one eye randomised) (randomized count) (Revised indications for the treatment of retinopathy of prematurity: results of the early treatment for retinopathy of prematurity randomized trial, retrieved 2026-10-15)
84 cases of asymmetric ROP (the one eye with high-risk prethreshold ROP randomised) (randomized count) (Revised indications for the treatment of retinopathy of prematurity: results of the early treatment for retinopathy of prematurity randomized trial, retrieved 2026-10-15)
Sponsor: Not recorded
Funder: Not recorded
Registry: Not reported
Started: 2001-10 (The Early Treatment for Retinopathy of Prematurity Study (ETROP), retrieved 2026-10-15)
Primary completion: Not reported
Completion: Not reported
Countries: United States (The Early Treatment for Retinopathy of Prematurity Study (ETROP), retrieved 2026-10-15)
Care setting: Not reported
Registry status: “UNKNOWN” (U.S. National Library of Medicine (ClinicalTrials.gov), retrieved 2026-10-15)

Technical summary

Registry NCT00027222 (phases 2 and 3, status UNKNOWN, last update posted 2005-06-24, lead sponsor the National Eye Institute) and the 2003 report (PubMed abstract only). The registry gives no enrolment count, no completion dates and no results. The abstract gives 317 infants with bilateral disease and 84 asymmetric cases; no total is stated and none is computed here. The registry lists eligibility as infants under 1251 g birth weight born at participating centres and/or examined by 42 days of life, and a maximum age of 42 days.

Arms

Early treatment

Intervention None named

Eye randomised to early treatment by ablation of the avascular retina in high-risk prethreshold ROP.
Conventional management

Intervention None named

Control eye: the fellow eye managed conventionally (bilateral cases), or the eye randomised to conventional management (asymmetric cases).

Findings

No findings are published for this study.

Claims and evidence

Context Infants with high-risk prethreshold retinopathy of prematurity (ETROP trial)

Recipient: Newborn
Population: Infants with bilateral high-risk prethreshold ROP (317) had one eye randomised to early treatment and the other eye managed conventionally; in asymmetric cases (84) the one eye with high-risk prethreshold ROP was randomised to early treatment or conventional management. High risk was decided with a model built on the natural history cohort of an earlier cryotherapy trial. The outcomes are counted per eye. Under the registry, infants of birth weight under 1251 g, born at participating centres and/or examined by 42 days of life, were eligible, and the early treatment trial required prethreshold ROP.
Care setting: Not stated in the abstract
Geography: United States (ClinicalTrials.gov locations)
Life stage: Infants with high-risk prethreshold retinopathy of prematurity, followed to a corrected age of 9 months
Gestational age: Not reported
Postnatal age: Not reported
Follow-up: Visual acuity was assessed at a corrected age of 9 months by masked testers using Teller acuity cards; eyes were examined for structural outcome at corrected ages of 6 and 9 months.

Eligibility: 2 inclusion criteria; exclusion criteria not stated

Included: Infants with bilateral high-risk prethreshold ROP, or asymmetric ROP in which one eye had high-risk prethreshold ROP
Birth weight under 1251 g, born at participating centres and/or examined by 42 days of life (registry)
Excluded: None stated

Effect Interventional Certainty not assessed

In ETROP, early treatment of high-risk prethreshold retinopathy of prematurity (ablation of the avascular retina) was compared with conventional management. In infants with both eyes affected, one eye was randomised to early treatment and the fellow eye was managed conventionally; in asymmetric cases the one eye with high-risk prethreshold ROP was randomised to early treatment or to conventional management. With earlier treatment, unfavourable grating visual acuity at a corrected age of 9 months fell from 19.5% to 14.5% (P=.01) and unfavourable structural outcomes at 9 months fell from 15.6% to 9.1% (P<.001). Further analysis supported retinal ablation for type 1 ROP (zone I, any stage with plus disease; zone I, stage 3 without plus disease; or zone II, stage 2 or 3 with plus disease) and a wait-and-watch approach for type 2 ROP (zone I, stage 1 or 2 without plus disease; or zone II, stage 3 without plus disease), which should be considered for treatment only if it progresses to type 1 or threshold ROP. The authors say early treatment significantly reduced unfavourable outcomes to a clinically important degree.
Applies to Newborn
- Infants with bilateral high-risk prethreshold ROP (317) had one eye randomised to early treatment and the other eye managed conventionally; in asymmetric cases (84) the one eye with high-risk prethreshold ROP was randomised to early treatment or conventional management. High risk was decided with a model built on the natural history cohort of an earlier cryotherapy trial. The outcomes are counted per eye. Under the registry, infants of birth weight under 1251 g, born at participating centres and/or examined by 42 days of life, were eligible, and the early treatment trial required prethreshold ROP.
- Not stated in the abstract
- United States (ClinicalTrials.gov locations)
- Infants with high-risk prethreshold retinopathy of prematurity, followed to a corrected age of 9 months
- Gestational age Not reported
- Postnatal age Not reported
Follow-up Visual acuity was assessed at a corrected age of 9 months by masked testers using Teller acuity cards; eyes were examined for structural outcome at corrected ages of 6 and 9 months.
Certainty method
Not assessed

Limitations
Only the abstract was read. The analysis combines bilateral and asymmetric cases and counts eyes, not infants. Follow-up in this paper ends at a corrected age of 9 months; the authors say long-term follow-up was being conducted. The grouping into type 1 and type 2 ROP comes from further analysis that led to modified treatment recommendations; it is not a separate trial. The abstract does not give how many eyes were in each group.

Last checked
2026-10-15

Next evidence check due
Not scheduled
Sources and citations (2)
1. Supports Revised indications for the treatment of retinopathy of prematurity: results of the early treatment for retinopathy of prematurity randomized trial
  
  Publication · Archives of ophthalmology (Chicago, Ill. : 1960) · Edition PubMed record (abstract and bibliographic data) from NCBI E-utilities. The full text and the version of record were not fetched. · DOI: 10.1001/archopht.121.12.1684 · PMID: 14662586
  
  Locator
  Abstract, RESULTS sentences 1 to 5 and CONCLUSIONS sentence 1
  
  How it applies
  Visual acuity, structural outcome and the type 1 and type 2 findings.
  
  Retrieved
  2026-10-15T13:49:23Z
  
  Source effective date
  Not reported
  
  Source state
  Current
  
  Snapshot hash
  3a686b6dbcc138d824b4b8b24d3c68588e1ddb859742bee2667f7a5038c7e31c
  
  Reuse basis
  PubMed record fetched through NCBI E-utilities. Only the hash of the bytes is kept, because publisher copyright may apply to the abstract (https://pubmed.ncbi.nlm.nih.gov/disclaimer/). Short factual quotations under 25 words, with the citation.
2. Background Revised indications for the treatment of retinopathy of prematurity: results of the early treatment for retinopathy of prematurity randomized trial
  
  Publication · Archives of ophthalmology (Chicago, Ill. : 1960) · Edition PubMed record (abstract and bibliographic data) from NCBI E-utilities. The full text and the version of record were not fetched. · DOI: 10.1001/archopht.121.12.1684 · PMID: 14662586
  
  Locator
  Abstract, OBJECTIVE, METHODS and CONCLUSIONS sentence 3
  
  How it applies
  Design, groups, outcome assessment and follow-up.
  
  Retrieved
  2026-10-15T13:49:23Z
  
  Source effective date
  Not reported
  
  Source state
  Current
  
  Snapshot hash
  3a686b6dbcc138d824b4b8b24d3c68588e1ddb859742bee2667f7a5038c7e31c
  
  Reuse basis
  PubMed record fetched through NCBI E-utilities. Only the hash of the bytes is kept, because publisher copyright may apply to the abstract (https://pubmed.ncbi.nlm.nih.gov/disclaimer/). Short factual quotations under 25 words, with the citation.

Record details

Record id: maternal:etrop-trial
Content hash: 181227d1af01716c888bb1def9dc1cfb525bc0a93e3bca0ed8971c2f4119293f