Retinopathy of Prematurity (ROP)

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Indication for screening

  • Birth < 31+0 weeks or birth weight < 1250g 1
  • Premature infants (< 37+0) at risk for ROP development:
    • Oxygen therapy of more than 5 days
    • Relevant concomitant diseases (e.g. severe necrotising enterocolitis, bronchopulmonary dysplasia, sepsis, anaemia requiring transfusion)

Timing of screening examinations

  • Initial screening: 4 weeks after birth but not before 31+0 postmenstrual age 1
  • Follow-up examinations
    • 2-weekly normally
    • weekly or more closely if:
      • Vascularisation border in zone I or posterior zone II.
      • Vascularisation border in anterior zone II in stage 2 or 3 ROP
      • in any ROP with Plus disease
    • 3-weekly if vascularisation border in zone III without any ROP
    • Extend follow-up intervals by 1 week if
      • repeated improved findings
      • Calculated date of birth exceeded
  • Finish screening of patients without therapy if
    • Peripheral retina completely vascularised
    • after the calculated date of birth if there is a clear regression of ROP findings

Stages and Zones (ICROP)

  • Overview Zones, Stages, Plus Disease, Aggressive ROP (A-ROP) 2,
  • Stage 1 3: Demarcation line (thin, flat, whitish line between the normally vascularised retina and the avascular peripheral retina).
  • Stage 2 3: Visible ridge (with height and widtgh, extending beyond retinal level)
  • Stage 3 3: Prominent ridge with blood vessels and extraretinal fibrovascular proliferations (extending from ridge into vitreous)
  • Stage 4 3: Partial retinal detachment
    • 4A: extrafoveal
    • 4B: foveal
  • Stage 5: Total retinal detachment
  • Plus disease 3 = tendency to progression, poor prognostic sign
    • dilated veins and tortuous arteries in at least two quadrants
    • no pupil dilation
    • massively congested iris vessels
    • vitreous opacity
    • increasing pre-retinal and vitreous haemorrhages
  • “Pre-plus”: is defined by abnormal dilatation and tortuous vessels, not yet sufficient to be called plus disease
    • Weekly follow-up necessary until regression or progression to threshold disease
  • Threshold disease:
    • Blindness in 50% without therapy
    • 5 continuous or 8 non-continuous clock hours of extraretinal neovascularisation (stage 3) in zone 1 or 2 associated with plus disease
    • Therapy required: laser therapy of avascular immature retina within 48-72h
  • Aggressive (posterior) ROP (A-ROP) 3:
    • Posterior location in zone I or posterior zone II, plus disease, ill-defined nature of the retinopathy, rapidly progressing
    • If untreated, usually leads to stage 5


  • usually both eyes are treated (unless the opposite eye has minimal/no ROP)
  • should be done within 48-72h
  • Laser therapy in type 1, watch & wait in type 2 (according to ETROP study)
    • Type 1 (laser therapy)
      • Zone 1, all stages with plus disease
      • Zone 1, stage 3 without plus disease
      • Zone 2, stage 2+3 with plus disease
      • A-ROP
    • Type 2 (watch & wait)
      • Zone 1, stage 1+2 without plus disease
      • Zone 2, stage 3 without plus disease
    • Technique: treat the entire avascular area anterior to the demarcation line, avoid the fovea, burns near confluent / max. 0.5 burn-width apart, cloud grey appearance
  • anti-VEGF therapy (Ranibizumab 0.2mg) as an alternative
    • for zone I and posterior zone II
      • for zone II/III (except posterior II) laser therapy recommended
    • avoid if any sign of pericular infection!
    • Technique: under anaesthesia, 30g needle, 0.02ml syringe, 1-1.5mm from limbus, caution: needle not too anteriorly because of large cristalline lens; examine fundus with dilated pupils after injection for adverse effects

Follow-up (without therapy)

  • 6 months (optional)
  • 12 months (mandatory)
  • every 6 months in the 2nd year of life
  • annually from 3 – 6 years of age
  • from 6 years on if any ocular problems

Follow-up (after laser therapy)

  • Local therapy: e.g. Dexafree UD (Dexamethason) 4x/d + Mydriaticum gtt (Tropicamid) 2x/d for 1 week
  • After approx. 1 week: Examine anterior segments for adverse effects, disease regression?
  • after 2 weeks: Disease regression?
    • if not and laser incomplete: repeat laser treatment
    • if not and laser complete: consider rescue treatment with anti-VEGF
  • after 3-4 weeks: disease regression?
  • after 2-3 months, 6 months: Retinal examination
  • 12, 18, 24 months, thereafter annually until at least 5 years: orthoptic evaluation (visual acuity, strabismus, refraction in cycloplegia), examination of retina

Follow-up (after anti-VEGF)

  • after 1-2 days and 5-7 days: Examine anterior segments for adverse effects, disease regression?
  • then screening for disease reactivation (new Plus, new extraretinal vessels)
    • 1x/week for 4 weeks
    • 2-weekly for 12 weeks
    • 4-weekly for 8-16 weeks, (longer for A-ROP)
    • thereafter at 12, 18, 24 months, then annually until at least 5 years: orthoptic evaluation (visual acuity, strabismus, refraction in cycloplegia), examination of retina
  • If no regression <1-2 weeks or reactivation during the course: laser therapy recommended (alternatively, repetition of anti-VEGF possible).


  • Risk of ROP requiring treatment based on gestational age (weeks) 4: 24 (14.5%), 25 (7.3%), 26 (2.7%), 27 (1.1%), 28 (0.5%), 29-31 (0.06%), total 1.2%.
  • Spontaneous regression occurs in approx. 80% of ROP patients
  • Significantly increased risk (approx. 2/3 of all treated patients) of ocular problems: Myopia (with laser approx. 1/3 of patients with approx. -5dpt.), strabismus, reduction in visual acuity.
  • Average visual acuity (after successful retinal surgery) at stage 4: >0.1 to light perception, at stage 5: light perception to no light perception


  • AWMF Leitlinie Augenärztliche Screening-Untersuchung bei Frühgeborenen
  • EyeWiki Retinopathy of Prematurity
  • The Wills Eye Manual: Office and Emergency Room Diagnosis and Treatment of Eye Disease; Nika Bagheri MD, Brynn Wajda MD, et al; Lippincott Williams&Wilkins; 7th Edition (2016)
  • Kanski’s Clinical Ophthalmology: A Systematic Approach; Jack J. Kanski MD, Brad Bowling MD; Saunders Ltd.; 8th Edition (2015)
  • Good WV; Early Treatment for Retinopathy of Prematurity Cooperative Group. Final results of the Early Treatment for Retinopathy of Prematurity (ETROP) randomized trial. Trans Am Ophthalmol Soc. 2004;102:233-250.
  • Treating Retinopathy of Prematurity in the UK, Clinical Guidelines 2022, The Royal College of Ophthalmologists
  • 1 translated from © Luzerner Kantonsspital,, Authors: Dr. med. M. Fontana, Dr. med. Christoph Amstutz, Dr. med. Maria Helfenstein, Valentina Da Crosta
  • 2 © 2020 London School of Hygiene & Tropical Medicine (CC-BY-NC-SA 4.0)
  • 3 Molinari A, Weaver D, Jalali S. Classifying retinopathy of prematurity. Community Eye Health. 2017;30(99):55-56. PMID: 29434438; PMCID: PMC5806220. © 2017 Andrea Molinari, Dan Weaver and Subhadra Jalali, Creative Commons Attribution Non-Commercial License
  • 4 Gerull R et al. Incidence of retinopathy of prematurity (ROP) and ROP treatment in Switzerland 2006-2015: a population-based analysis. Arch Dis Child Fetal Neonatal Ed. 2018 Jul;103(4):F337-F342. doi: 10.1136/archdischild-2017-313574