Importance of Birth Weight as a Risk Factor for Severe Retinopathy of Prematurity When Gestational Age Is 30 or More Weeks

We read with great interest the recent article by Pierce and associates. They concluded that the occurrence rate of retinopathy of prematurity (ROP) requiring treatment in infants with gestational age (GA) of 30 or more weeks and birth weight (BW) less than 1500 grams is very low, and could indicate the need to revise examination guidelines for this subgroup of infants.

Although the results are interesting, we have a few concerns and comments. There are no details regarding the type and extent of comorbidities in the study population that are known to affect the occurrence and severity of ROP. In the context of multiple examiners with different levels of ROP expertise, as in the current article, photographic documentation of the retinal findings and subsequent analysis by another masked observer (preferably a retina specialist) could have been more meaningful. The authors mention that they screened the babies for the first time at 4–5 weeks of chronological age. However, there is no information as to why a baby born at 32 weeks was screened at 34 weeks (ie, at 2 weeks of chronological age). Except for a description of mild ROP to a certain extent, terminologies such as severe and treatable ROP are not defined by the authors. Of the 9 babies with mild ROP, 5 showed zone III vascularization but there is no mention of what happened to the other 4.

In an attempt to validate the authors’ hypothesis, we retrospectively analyzed our 5-year ROP database in 2 groups. In Group 1, we included babies with criteria set by the American Academy of Pediatrics, similar to the present article (ie, GA ≥30 weeks and BW <1500 grams). In Group 2, we modified the criteria as per our regional standards of screening set by the National Neonatology Forum (NNF), India, and included babies with GA ≥34 weeks and BW <1750 grams. Out of 396 eligible babies in Group 1, 196 had ROP and 30 of them required treatment. There were 179 babies in Group 2, of which 39 showed ROP of a certain degree and 6 required treatment. Interestingly, when we subdivided the Group 2 patients in terms of presence or absence of systemic comorbidities, we found that those who did not have collateral health problems rarely reached a treatable stage (only 1 out of 179), compared to 5 with comorbidities. So we conclude that babies with GA greater than but BW less than the regional standards of screening still have a possibility of treatable ROP in a significant population and cannot be ignored. But in the subgroup with no systemic comorbidities, the chance of developing treatable ROP is very low and probably one can err in reviewing them at a longer interval than the existing standards.

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Jan 8, 2017 | Posted by in OPHTHALMOLOGY | Comments Off on Importance of Birth Weight as a Risk Factor for Severe Retinopathy of Prematurity When Gestational Age Is 30 or More Weeks

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