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Randomised controlled pilot trial comparing low dose and very low- dose microdrop administration of phenylephrine and cyclopentolate for retinopathy of prematurity eye examinations in neonates


Aims To determine if

  • Very low dose mydriatic eye microdrop regimen sufficiently dilates the pupil (above 4.1 mm) compared with the currently used low dose mydriatic eye microdrop regimen.

  • Cardiovascular, gastrointestinal and respiratory adverse effects occur following eye drop instillation.

Methods Seventeen premature infants were recruited into this prospective, randomised controlled pilot trial in January 2017 to November 2018. Data were collected from the single-centre Neonatal Intensive Care Unit, Dunedin Hospital, New Zealand. The inclusion criteria were birth weight less than 1500 g or gestational age less than 31 weeks, or any premature infant requiring red reflex testing. Infants were randomised to receive either phenylephrine 1% or 0.5% and cyclopentolate 0.2% or 0.1%, 1 microdrop in both eyes. Efficacy outcome measures were pupil size at retinopathy of prematurity eye examination (ROPEE) and ophthalmologist rating of ease of screen.

Results All participants had sufficient pupillary dilation for a successful ROPEE. Ophthalmologists rated the ROPEE as easy for 90% of all examinations. Pupil dilation measurements at the time of examination, mean±SD, 4.8±0.2 (95% CI 4.5 to 5.2) mm for treatment A and 5±0.2 (95%CI 4.6 to 5.4) mm for treatment B (p=0.61). There were no statistically significant differences between the groups for safety data.

Conclusions Very low dose microdrop administration of phenylephrine and cyclopentolate appears to be effective at sufficiently dilating the neonatal pupil for ROPEEs. Low dose and very low dose microdrop mydriatic regimens may also reduce the risk of unwanted adverse effects associated with these medicines.

Trial registration number Australian New Zealand Clinical Trials Registry (reference ACTRN12616001266459p).

  • neonatology
  • ophthalmology
  • phenylephrine
  • cyclopentolate
  • retinopathy of prematurity

Data availability statement

Data are available on reasonable request. IPD and related data dictionaries are available. All non-­identifiable data; individual participant data underlying published results only. Data will be available immediately following publication and until 31 December 2021. Data are available only to researchers who provide a methodologically sound proposal, on a case­-by-case basis, at the discretion of this study's PI. Data will be provided for any type of analyses, only to achieve the aims in the approved proposal, for IPD meta-analyses, as deemed fit by this study's PI. Data can be obtained by access subject to approvals by this study's Principal Investigator, with a requirement to sign a data access agreement. The study protocol, informed consent form and ethical approval are also available if needed.

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