Red reflex test at the maternity hospital: results from a tertiary hospital and variables associated with inconclusive test results.

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.