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Incidence, timing and risk factors of type 1 retinopathy of prematurity in a North American cohort
  1. Yinxi Yu1,
  2. Lauren A Tomlinson2,
  3. Gil Binenbaum2,
  4. Gui-shuang Ying1
  5. the G-Rop Study Group
  1. 1 Center for Preventive Ophthalmology and Biostatistics, Scheie Eye Institute, Department of Ophthalmology, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania, USA
  2. 2 The Children’s Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
  1. Correspondence to Gui-shuang Ying, 3711 Market Street, Suite 801, Philadelphia, PA 19104, USA; gsying{at}


Background/Aims Early detection and timely treatment of type 1 retinopathy of prematurity (ROP) can reduce the risk of blindness. To evaluate the incidence, timing and risk factors of type 1 ROP in a large, broad-risk cohort of premature infants.

Methods Secondary analysis of data from the two Postnatal Growth and Retinopathy of Prematurity studies. Main outcomes are the incidence and timing of type 1 ROP.

Results Among 11 463 infants (mean birth weight (BW), 1095 g; mean gestational age (GA), 28 weeks), 677 (5.9%, 95% CI 5.5% to 6.3%) developed type 1 ROP. Rate of type 1 ROP decreased with larger GA (28.8% for GA ≤23 weeks, 0.2% for GA of 31–32 weeks) and no infants with GA >32 weeks developed type 1 ROP. Type 1 ROP was first diagnosed at a median postmenstrual age (PMA) of 36 weeks (range 30–46 weeks) or postnatal age (PNA) of 11 weeks (range 5–21 weeks). The mean PMA at diagnosis of type 1 ROP increased with GA (35 weeks for GA of 22–24 weeks, 41 weeks for GA of 29–30 weeks), but the mean PNA at diagnosis of type 1 ROP was similar (11–13 weeks) across GA of 22–29 weeks. GA and BW dominate the association (area under the receiver operating characteristic curve=0.87, 95% CI 0.86 to 0.88).

Conclusions Type 1 ROP developed in about 6% of premature infants over wide time windows in terms of both PMA and PNA. BW and GA are the dominant risk factors for type 1 ROP, while other prenatal factors add minimal predictive power for type 1 ROP.

  • Child health (paediatrics)
  • Epidemiology
  • Retina
  • Vision

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  • Portions of this data were presented at ARVO and 146th Scheie Eye Institute Anniversary Meeting in May 2020.

  • Contributors YY and G-SY had full access to study data and take responsibility for the integrity of the data and accuracy of the analysis. YY, GB and G-SY participated in study design, manuscript writing and critically reviewing the manuscript. LAT participated in study design and critically reviewing the manuscript. YY performed the statistical analysis. All authors approved the final manuscript.

  • Funding This work was supported by National Institutes of Health (grants 1R01EY021137-01A1 and 1R21EY029776-01). The Children’s Hospital of Philadelphia was the study headquarters and the Children’s Hospital of Philadelphia’s IRB protocol numbers are IRB 12-009727 (G-ROP-1) and IRB 15-012258 (G-ROP-2). All participating hospitals in the multicenter G-ROP were approved as well.

  • Competing interests None declared.

  • Provenance and peer review Not commissioned; externally peer reviewed.

  • Data availability statement No data are available.

  • Supplemental material This content has been supplied by the author(s). It has not been vetted by BMJ Publishing Group Limited (BMJ) and may not have been peer-reviewed. Any opinions or recommendations discussed are solely those of the author(s) and are not endorsed by BMJ. BMJ disclaims all liability and responsibility arising from any reliance placed on the content. Where the content includes any translated material, BMJ does not warrant the accuracy and reliability of the translations (including but not limited to local regulations, clinical guidelines, terminology, drug names and drug dosages), and is not responsible for any error and/or omissions arising from translation and adaptation or otherwise.

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