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



To study the efficacy and safety of mydriatic microdrops compared with standard drops for retinopathy of prematurity (ROP) screening.

Study design

Preterm infants undergoing ROP screening received microdrops and standard drops of phenylephrine 1.67% and tropicamide 0.33% in a random allocation sequence at two consecutive weekly examinations. Primary outcome was pupil diameter measured by two masked observers at 45 (T45) and 90 (T90) minutes after instillation.


Twenty-five infants were randomized. No differences observed in mean pupil diameter after either administration technique at all time points (T45 Mean Difference: −0.14; 95% Confidence Interval: −0.38, 0.09; p = 0.23). Heart rate values at T120 were lower after microdrop instillation (p = 0.046). Otherwise, adverse events did not differ after either administration technique.


This pilot study provides evidence of microdrops mydriasis efficacy, while justifying a full-scale trial to confirm their non-inferiority compared with standard drops and provide more data about safety.

Trial registration NCT04623684.

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Fig. 1: The microdrop instillation device and the ruler that were used in the present pilot study.
Fig. 2


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Author information




AKS, ML, EG, ABH, and AM contributed to the conception and design of the study. AKS was involved in the assignment of interventions. ML and AM were involved in the recruitment and screening of trial participants and data collection. AKS, PT, ABH, and AM performed data analysis. All authors (AKS, ML, PT, EG, ED, NZ, ABH, and AM) contributed to the interpretation of the data. AKS, PT and AM prepared the initial draft manuscript. All authors (AKS, ML, PT, EG, ED, NZ, ABH, and AM) were involved in the revision and edit of the manuscript. All authors (AKS, ML, PT, EG, ED, NZ, ABH, and AM) approved the final version to be published and are responsible for accuracy and integrity of all aspects of research.

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Correspondence to Asimina Mataftsi.

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Seliniotaki, A.K., Lithoxopoulou, M., Talimtzi, P. et al. Efficacy and safety of mydriatic microdrops for retinopathy of prematurity screening: an external pilot crossover randomized controlled trial. J Perinatol (2021).

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