RESUMO
OBJECTIVES: Describe the results of the red reflex test in full-term newborns, as well as identify factors associated with red reflex test outcome and compare hospital length of stay between patients with inconclusive and normal red reflex test results. METHODS: Descriptive cross-sectional study of the results of the red reflex test performed in a tertiary hospital maternity unit between 2014 and 2018. A nested case-control study was also performed to search for anthropometric, gestational, and neonatal variables associated with the outcome of the red reflex test. RESULTS: There were121 identified cases of inconclusive red reflex test in 11,833 newborns. Sixteen alterations were confirmed, four considered severe: two cases of congenital glaucoma, one of cataract, and one of coloboma. Mean birth weight (p=0.04), length (p=0.03), and head circumference (p=0.02) were lower in patients with inconclusive red reflex test; however without a relevant effect size (d=-0.21, -0.22, and -0.25, respectively).The proportion of white, mixed-race, and black patients was significantly different between the groups (p<0.001), with a higher chance of inconclusive results in mixed-race (OR=2.22) and black (OR=3.37) patients when compared to whites. An inconclusive red reflex test led to an increase in hospital length of stay from 62 to 82hours (p<0.001). CONCLUSIONS: The red reflex test was able to identify four severe alterations in 11,833 newborns (0.03%). In the 121 newborns in which the red reflex test was classified as inconclusive, there was a 20-hour increase in the hospital length of stay, but a severe alteration was confirmed in only 3.3% of them. Differences in red reflex between white, mixed-race, and black patients should be considered.