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Retinopathy of prematurity (ROP)
In retinopathy of prematurity the retinal vessels, which have not finished growing to the periphery, continue to grow abnormally after preterm birth; at-risk infants are screened with repeated fundus examinations, and when type 1 ROP is reached laser or anti-VEGF is given within 72 hours to prevent retinal detachment and blindness.
Why it matters in the exam
Screening criteria (AAP 2018): birth weight of 1500 grams or less, or gestational age of 30 weeks or less, and also heavier or more mature infants with an unstable course at the neonatologist's discretion. The first examination: at a postmenstrual age of 31 weeks or 4 weeks after birth — whichever is later. Risk factors: low gestational age, low birth weight, oxygen exposure and fluctuating saturation, sepsis and poor weight gain.
The classification (ICROP3): zone I — a circle around the disc with a radius twice the disc–fovea distance, zone II to the nasal ora serrata, zone III — the remaining temporal crescent. Stages: 1 — demarcation line; 2 — ridge; 3 — extraretinal fibrovascular proliferation; 4 — partial detachment (4A sparing the fovea, 4B involving the fovea); 5 — total detachment. Plus disease — dilation and tortuosity of the posterior vessels, a sign of activity. A-ROP — an aggressive form that progresses fast without passing through the stages, mainly in zone I.
According to ETROP, type 1 ROP requires treatment: zone I any stage with plus; zone I stage 3 even without plus; zone II stage 2 or 3 with plus. Type 2 ROP — close follow-up. Treatment: laser to the avascular retina, or anti-VEGF injection (bevacizumab, ranibizumab) — an advantage in zone I, but with a risk of late recurrence and therefore longer follow-up. Later in life: high myopia, strabismus, amblyopia and retinal detachment, so eye follow-up continues through childhood.
Key points
- Immature vessels continue to grow abnormally.
- Screening: up to 1500 grams or up to 30 weeks.
- First examination: 31 weeks postmenstrual or 4 weeks after birth.
- Type 1 ROP → laser or anti-VEGF within 72 hours.
- Childhood follow-up: myopia, strabismus, amblyopia.
Summary table
| Term | Definition | Significance |
|---|---|---|
| Zone I | Posterior circle around the disc | The most severe |
| Stage 3 | Extraretinal proliferation | A stage that may need treatment |
| Plus disease | Dilated tortuous posterior vessels | Sign of activity; decisive for treatment |
| Type 1 ROP | Zone I with plus or stage 3; zone II stage 2–3 with plus | Treat within 72 hours |
| Type 2 ROP | Less than type 1 | Close follow-up |
| A-ROP | Rapid progression in a posterior zone | Immediate treatment |
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Sources
- American Academy of Pediatrics / AAO / AAPOS: Screening Examination of Premature Infants for Retinopathy of Prematurity, 2018 — Screening criteria and timing
- International Classification of Retinopathy of Prematurity, Third Edition (ICROP3), 2021 — Zones, stages, plus disease and A-ROP
- Early Treatment for Retinopathy of Prematurity (ETROP) Cooperative Group, 2003 — Type 1 and type 2 ROP
Sources are given for further reading; the text is written afresh and not copied from them.
Reviewed by the Examqo AI Professor · 2026-11-06. The text may contain errors; when in doubt, check the source.