Cyclopentolate Hydrochloride/Phenylephrine Hydrochloride

Retinopathy of prematurity (ROP) is one of the common anatomic causes of blindness among Filipinos, accounting for 47.7% of the cases. With this retinopathy being preventable and treatable, ROP screening has been proven to be effective in preventing blindness, which is achieved with the usage of mydriatics. Even if the regimen of multiple alternate instillations of 0.5% tropicamide and 2.5% phenylephrine is the one recommended by international guidelines for ROP screening, the mydriatic regimen used by many of the country's institutions is the single instillation of 0.5% tropicamide + 0.5% phenylephrine applied via a cotton wick placed in the inferior fornix (SIW). There have been no studies yet on the safety and efficacy in premature infants of this mydriatic preparation and method, although it is hypothesized that the usage of a cotton wick promotes the possible systemic effects of the mydriatic combination used.
This study then aims to determine the safety and efficacy of different mydriatic regimens in premature infants referred for screening of ROP using (1) multiple alternate instillations of 0.5% cyclopentolate hydrochloride and 2.5% phenylephrine (MAI), (2) single instillation of 0.5% tropicamide + 0.5% phenylephrine (SI), and (3) single instillation of 0.5% tropicamide + 0.5% phenylephrine with a cotton wick placed in the inferior fornix (SIW) in a tertiary Philippine hospital.
This study was designed as a randomized, double blind, clinical study which enrolled sixty preterm infants referred for ROP Screening from January to July 2011. With instillations via MAI, SI, and SIW, systolic blood pressure (SBP), diastolic pressure (DBP), mean arterial pressure (MAP), heart rate, and oxygen saturation were monitored from ten minutes prior to instillation up to forty-five minutes after instillation. Pupil dilations were also measured at the forty-fifth minute.