Timing of First ROP Screening Examination in Newborns
The first retinopathy of prematurity (ROP) screening examination should be performed at the later of either 31-33 weeks postmenstrual age or 4 weeks chronological age. 1
Screening Criteria Based on Gestational Age and Birth Weight
- Infants requiring ROP screening include those with gestational ages of 30 6/7 weeks or less (regardless of birth weight) and birth weights of 1250 g or less (regardless of gestational age) 2
- Some centers may choose to extend birth weight screening criteria to 1500 g based on local factors 2
- Infants with more than 37 weeks of gestation at birth do not need to be screened 1
- Infants between 29 and 37 weeks may not need screening if they had a "medically stable" course (no supplemental oxygen requirement) 1
- A more conservative approach is to screen all infants with less than 32 weeks of gestation at birth, even if medically stable 1
Timing of Initial Examination
- For infants with gestational ages of 26 6/7 weeks or less at birth: Initial screening should be performed at 31 weeks postmenstrual age 2
- For infants with gestational ages of 27 weeks or more at birth: Initial screening should be performed at 4 weeks chronological age 2
- The examination should be conducted by an ophthalmologist experienced in the evaluation of ROP in premature infants 1
Evidence Supporting These Recommendations
- Analysis of data from the CRYO-ROP study showed that in 99% of infants, retinal conditions indicating risk of poor outcome were not observed before 31 weeks postmenstrual age or 4 weeks chronological age 3
- A recent study of extremely preterm infants (<27 weeks gestation) found that no infants required laser therapy for ROP prior to 32 weeks PMA, supporting the recommendation to initiate screening at 31 weeks PMA 4
- Earlier studies had suggested that extremely low birth weight infants (<1000g) might benefit from earlier screening using the chronological age guideline of 4-6 weeks rather than waiting until 31-33 weeks postmenstrual age 5
- However, more recent evidence confirms that even in extremely preterm infants, severe ROP requiring treatment does not develop before 31 weeks PMA 4, 6
Follow-up Examinations
- Subsequent examinations are based on the findings at the first screening and should follow the ophthalmologist's recommendation 2
- The mean interval between examinations is approximately 7-9 days 6
- Screening can be discontinued when any of these signs is present 3:
- Infant attains 45 weeks postmenstrual age without development of prethreshold ROP or worse
- Progression of retinal vascularization into zone III without previous zone II ROP
- Complete retinal vascularization
Special Considerations for Infants with Chronic Lung Disease
- Infants with chronic lung disease of infancy (CLDI) rarely have a "medically stable" course during initial hospital weeks and should be screened even if between 29-37 weeks gestation 1
- For infants with unresolved ROP and CLDI being discharged home, careful coordination of follow-up ophthalmology appointments is crucial 1
- ROP that is regressing with vessels that have passed into Zone 3 on at least two sequential examinations is extremely unlikely to progress to threshold ROP 1
- Infants whose vessels and/or ROP are still in Zone 1 or Zone 2 are at higher risk for progression to threshold and require ophthalmology visits every 1-2 weeks 1
Importance of Timely Screening
- Early identification of prethreshold ROP is critical for providing timely intervention in this rapidly progressive disease 5
- Peripheral ablation for threshold ROP has proven effective in reducing blindness from ROP 1
- Missing follow-up appointments for infants still at risk for ROP progression can lead to missed opportunities for treatment and potentially preventable vision loss 1