Dr Fielder is correct in pointing out that the CRYO-ROP outcome study excluded certain infants at the outset, ie, those with major systemic or ocular congenital anomalies. This exclusion from the study denominator would indeed limit the utility of the data for certain purposes. Specifically, the protocol excluded infants with a clearly lethal and irreparable congenital anomaly. Examples include anencephaly, trisomy 13/15 or 18, or severe cardiopulmonary anomalies. Infants with anomalies that are amenable to treatment... and those compatible with survival, but not affecting the eyes... [were] included in the study.On the other hand, also excluded were those patients with "a major congenital abnormality of one or both eyes... that would potentially affect vision."1Of 9751 registered patients at the nurseries, 44 were excluded because of such anomalies.2 We thank Dr Fielder for contributing this excellent discussion of visual disorders in premature infants.
Palmer EA. The Natural Ocular Outcome of Premature Birth and Retinopathy: Status at 1 Year-Reply. Arch Ophthalmol. 1995;113(7):851. doi:10.1001/archopht.1995.01100070020009