The purpose is to test the hypothesis that microdrop instillation of cyclopentolate 1% is non-inferior to standard of care, i.e., standard drop instillation of cyclopentolate 1%. Comparison, also, will be made to the subsequent adverse events.

A non-inferiority, crossover, randomized controlled trial will be conducted for this purpose. Participants will be randomly assigned to receive either a) microdrops on their first and standard drops on their second screening examination a week later (M/S group), or b) standard drops first and microdrops a week later (S/M group). Microdrops will be instilled using the Nanodropper® device, while standard drops will be instilled directly through the commercially available plastic multidose mydriatic dropper bottle. For all participants, the eyedrop will be firstly instilled in the right eye and this will be the eye that will be used for the analyses. Written informed consent will be obtained from the parents/guardians for the children's enrollment.

Inclusion Criteria:

Children aged 4-16 years old, who require cycloplegic refraction measurements in the context of regular ophthalmological examination as outpatients in the 2nd Department of Ophthalmology of AUTh at a tertiary center in Northern Greece.

Exclusion Criteria:

1. Inability for the child to cooperate with autorefractometer
2. Difficulties for the family to attend the follow-up visit
3. Known allergic reaction to cyclopentolate or to any of the other ingredients of this solution
4. Presence of any contraindication for the child to receive cyclopentolate eyedrops (e.g. neurological disease of concern)