A pilot prospective randomized crossover clinical trial is conducted for assessing the mydriatic efficacy and safety of microdrops (6-7 μL) compared with standard drops (28-34 μL) for retinopathy of prematurity screening. A random number table was used to allocate participants into either a) receiving standard drop on their first and microdrop on their second screening examination a week later, or b) receiving microdrop first and standard drop a week later. The mydriatic agent contains phenylephrine 1.67% and tropicamide 0.33%, which derives from compounding the commercial phenylephrine 5% with the commercial tropicamide 0.5% in volume ratio 1:2.
The purpose is to assess whether the use of microdrop instillation of phenylephrine 1.67% and tropicamide 0.33% maintains mydriatic efficacy while presents an improved safety profile compared with standard drops of phenylephrine 1.67% and tropicamide 0.33%, which is routine care for pupil dilation during retinopathy of prematurity (ROP) screening in our neonatal intensive care unit.