Maximum atropine dose without clinical signs or symptoms

Area of Science:

• Ophthalmology
• Clinical Pharmacology

Background:

• High-dose atropine (1%) effectively slows myopia progression but causes significant side effects like pupil dilation and blurred vision.
• Lower concentrations (0.01% to 0.5%) show promise for myopia control with fewer adverse effects.

Purpose of the Study:

• To identify the maximum atropine concentration that effectively controls myopia without causing significant pupillary mydriasis or accommodative paralysis.

Main Methods:

• A Phase I clinical trial involving 12 subjects.
• Accommodation measured by push-ups; pupillary dilation assessed via photography.
• Comfort criteria: ≥5D accommodation, ≤3mm inter-pupillary difference, minimal near-vision blur/photophobia.

Main Results:

• Atropine 0.02% was the highest concentration without significant clinical symptoms or signs.
• Mean pupillary dilation was 3mm, and mean accommodative amplitude was 8 diopters at 0.02%.
• Reducing concentration from 0.02% to 0.01% did not decrease clinical signs or symptoms.

Conclusions:

• Atropine 0.02% is the highest concentration that avoids significant symptoms of accommodative paresis and pupillary dilation.
• This concentration serves as an optimal starting point for evaluating low-dose atropine in slowing myopia progression.