Neosynephrine and tropicamide eyedrops for pupil dilation in premature infants is almost twice as efficient as tropicamide eyedrops alone

Abstract

AbstractPurpose Retinopathy of prematurity screening requires pupil dilation of premature infants. While essential for reliable fundus examination, proper dilatation may sometimes be difficult to achieve in this population. The aim of our study was to compare the efficacy of two mydriatic regimens: one consisting in three drops of tropicamide 0.5% and the other one consisting in two drops of tropicamide 0.5% with one drop of phenylephrine 5%.Methods Thirty premature infants were enrolled and each infant was dilated with one regimen in one eye and the other regimen in the other eye. The side of each regimen was determined by randomization. A photograph of each eye was taken. The photographs were anonymised and randomly presented to two independant readers. The effect of the two regimens was determined by calculating the ratio of pupil diameter divided by cornea diameter. Assuming that pupil and cornea are circle‐shaped, we calculated the ratio of pupil surface area relative to cornea surface area for both regimens.Results The pupil to cornea diameters ratio was 46.7% (+/‐8.8) with tropicamide alone and 65.2%(+/‐6.0) with tropicamide‐phenylephrine combination. The ratio of pupil to cornea surface areas was 21.8% with tropicamide alone and 42.6% with tropicamide‐phenylephrine combination. In other words, the pupil surface area was 1.95 fold greater with tropicamide‐phenylephrine combination than with tropicamide alone.Conclusion The use of a combination of two drops of tropicamide 0.5% with one drop of phenylephrine 5% is far more efficient than tropicamide alone to achieve proper pupil in premature infants.