Low dose or very low dose phenylephrine and cyclopentolate microdrops for retinopathy of prematurity eye examinations (The Little Eye Drop Study): a randomised controlled non-inferiority trial

ObjectiveTo determine if very low dose (VLD, 0.5% phenylephrine, 0.1% cyclopentolate) mydriatic microdrop (approximately 7 μL) administration (up to three doses) is non-inferior to low dose (LD, 1% phenylephrine, 0.2% cyclopentolate) mydriatic microdrop administration for ophthalmologist-determined successful retinopathy of prematurity eye examination (ROPEE).DesignMulticentre, prospective, randomised controlled, non-inferiority clinical trial.SettingFour neonatal intensive care units in Aotearoa, New Zealand from October 2019 to September 2021.PatientsInfants with a birth weight less than 1250 g or gestational age less than 30+6 weeks and who required a ROPEE.InterventionsThe intervention: microdrop (approximately 7 μL) of VLD (0.5% phenylephrine and 0.1% cyclopentolate) to both eyes, or the comparison: microdrop of LD (1% phenylephrine and 0.2% cyclopentolate) to both eyes. Up to three doses could be administered.Main outcome measuresThe primary outcome measure was an ophthalmologist-determined successful ROPEE.ResultsOne hundred and fifty preterm infants (LD mean GA=27.4±1.8 weeks, mean birth weight=1011±290 g, VLD mean GA=27.5±1.9 weeks, mean birth weight=1049±281 g,) were randomised. Non-inferiority for successful ROPEE was demonstrated for the VLD group compared with the LD group (VLD successful ROPEE=100%, LD successful ROPEE=100%, 95% CI no continuity correction −0.05 to 0.05) and for Māori (95% CI no continuity correction −0.02 to 0.19).ConclusionVLD microdrops enable safe and effective screening for ROPEE in both Māori and non-Māori preterm infants.Trial registration numberACTRN12619000795190.