Screening guidelines for retinopathy of prematurity: the need for revision in extremely low birth weight infants.

OBJECTIVE: To determine whether significant retinopathy of prematurity (ROP) can be detected before 31 to 33 weeks' postmenstrual age (PMA) in extremely low birth weight (ELBW) infants.

METHODS: Medical records of all ELBW infants (<1000 g at birth) admitted to our regional perinatal center between April 1995 and January 1999 were reviewed retrospectively. Screening examinations for ROP were routinely performed at 4 to 6 weeks' chronological age (CA) from birth and followed at least every other week. Data were collected for infants who developed ROP. We determined the PMA at which the first screening eye examination demonstrated prethreshold disease and the subsequent examination that showed threshold disease (if it occurred). The percentages of infants who developed prethreshold ROP diagnosed at </=31 weeks' PMA and of those who progressed to threshold ROP before 34 weeks' PMA were determined.

RESULTS: All 258 ELBW infants were screened for ROP. Seventy-eight infants (30%) were diagnosed with prethreshold ROP. Twenty-seven of these infants (35%) progressed to threshold ROP. Ten infants who progressed to threshold ROP were <34 weeks' PMA at the time of this diagnosis. Of these 10 infants, 3 were diagnosed at 31 weeks' PMA, 4 at 32 weeks', and 3 at 33 weeks'.

CONCLUSION: More than 80% of ELBW infants who developed prethreshold disease in this cohort were </=33 weeks' PMA. The joint statement screening option of independently using 31 to 33 weeks' PMA for the first eye examination would have led to a diagnosis of threshold ROP on first examination in as many as 13% (10/78) of our patients. Early identification of prethreshold ROP is important for providing timely intervention in this rapidly progressive disease. Therefore, ELBW infants should receive initial ROP screening using the CA guideline of 4 to 6 weeks rather than the 31- to 33-week postconceptional age guideline.