Efficacy and safety of mydriatic microdrops for retinopathy of prematurity screening: an external pilot crossover randomized controlled trial

An Evaluation of the Efficacy and Safety of Timolol Maleate 0.5% Microdrops Administered with the Nanodropper

PURPOSE

To examine if 12.5 μl timolol maleate 0.5% microdrops dispensed with the Nanodropper Adaptor provide noninferior intraocular pressure (IOP) reduction compared with conventional 28 μl drops in patients with open-angle glaucoma (OAG) and ocular hypertension (OHT).

DESIGN

Prospective, noninferiority, parallel, multicenter, single-masked, active-controlled, randomized trial.

PARTICIPANTS

Treatment-naïve subjects who were recently diagnosed with OAG and OHT at the Aravind Eye Care System.

METHODS

Both eyes of subjects received 1 commercially available drop or both eyes of subjects received 1 microdrop of timolol maleate 0.5%. We measured IOP, resting heart rate (HR), and blood pressure (BP) at baseline and 1, 2, 5, and 8 hours after timolol administration.

MAIN OUTCOME MEASURES

The IOP was the primary outcome measure. Secondary outcomes were resting HR, systolic BP (sBP), and diastolic BP (dBP).

RESULTS

Adaptor-mediated microdrops and conventional drops of timolol significantly decreased IOP compared with baseline at all timepoints. Noninferiority was established at 3 of 4 timepoints. Heart rate decreases with Nanodropper were approximately 3 beats per minute (bpm) less than with conventional drops.

CONCLUSIONS

Timolol microdrops appear to be as effective in ocular hypotensive action as conventional drops with a slightly attenuated effect on resting HR and BP.

FINANCIAL DISCLOSURE(S)

Proprietary or commercial disclosure may be found after the references.

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

OBJECTIVE

To 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).

DESIGN

Multicentre, prospective, randomised controlled, non-inferiority clinical trial.

SETTING

Four neonatal intensive care units in Aotearoa, New Zealand from October 2019 to September 2021.

PATIENTS

Infants with a birth weight less than 1250 g or gestational age less than 30+6 weeks and who required a ROPEE.

INTERVENTIONS

The 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 MEASURES

The primary outcome measure was an ophthalmologist-determined successful ROPEE.

RESULTS

One 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).

CONCLUSION

VLD microdrops enable safe and effective screening for ROPEE in both Māori and non-Māori preterm infants.

TRIAL REGISTRATION NUMBER

ACTRN12619000795190.

Acute drug reaction to phenylephrine and tropicamide collyrium in a late-preterm newborn: a case report

Background

Collyrium administration is a common procedure in the neonatal ward, both in preterm and at term babies. Various molecules are used to induce mydriasis and cycloplegia: among them, phenylephrine and tropicamide are the most popular, and their administration is generally considered safe.

Case presentation

A 35 + 2 weeks-old, 2510 g, well-appearing male newborn required an ophthalmologic evaluation after a doubtful red reflex test. A collyrium with 1% phenylephrine and 0.95% tropicamide was administered prior to the consult, one drop per eye. Two minutes after the administration, the baby developed a severe apnea that required tactile stimulation. Moreover, the area around his eyes became visibly pale. Three minutes later, the baby became severely bradycardic (59 bpm), but remained in good general condition, so that resuscitation maneuvers were not required. Bradycardia lasted for almost three hours and then gradually resolved.

Conclusions

Cardiopulmonary manifestations, such as bradycardia and even cardiopulmonary arrest, are severe complications that can happen after phenylephrine collyrium administration in preterm newborns. However, they have been described in babies below 1500 g or with concurrent respiratory manifestations. Our patient, on the other hand, was late preterm, and never required a ventilatory support prior to the collyrium administration. Practitioners who deal with premature babies, even if late preterm, must be aware of these possible complications and administer phenylephrine collyrium carefully, where cardiopulmonary resuscitation equipment and personnel are available.

Efficacy and safety of Mydriatic Microdrops for Retinopathy Of Prematurity Screening (MyMiROPS): study protocol for a non-inferiority crossover randomized controlled trial

BACKGROUND

Retinopathy of prematurity (ROP) eye examination screening presupposes adequate mydriasis for an informative fundoscopy of preterm infants at risk, on a weekly basis. Systemic absorption of the instilled mydriatic regimens has been associated with various adverse events in this fragile population. This report aims to present the fully developed protocol of a full-scale trial for testing the hypothesis that the reduced mydriatic drop volume achieves adequate mydriasis while minimizing systemic adverse events.

METHODS

A non-inferiority crossover randomized controlled trial will be performed to study the efficacy and safety of combined phenylephrine 1.67% and tropicamide 0.33% microdrops compared with standard drops in a total of 93 preterm infants requiring ROP screening. Primary outcome will be the pupil diameter at 45 (T45) min after instillation. Pupil diameter at T90 and T120 will constitute secondary efficacy endpoints. Mixed-effects linear regression models will be developed, and the 95% confidence interval approach will be used for assessing non-inferiority. Whole blood samples will be analyzed using hydrophilic liquid chromatography-tandem mass spectrometry method (HILIC-MS/MS), for gathering pharmacokinetic (PK) data on the instilled phenylephrine, at nine specific time points within 3 h from mydriasis. Pooled PK data will be used due to ethical restrictions on having a full PK profile per infant. Heart rate, oxygen saturation, blood pressure measurements, and 48-h adverse events will also be recorded.

DISCUSSION

This protocol is designed for a study powered to assess non-inferiority of microdrops compared with standard dilating drops. If our hypothesis is confirmed, microdrops may become a useful tool in ROP screening.

TRIAL REGISTRATION

ClinicalTrials.gov NCT05043077 . Registered on 2 September 2021.