Effect of caffeine and low intensity endurance exercise on intraocular pressure
Reviewed by Ivan Yip

This placebo controlled, double blind, balanced crossover study reports in healthy individuals that 30 minutes of cycling caused a maximum of 2.7mmHg lowering of IOP. A caffeine dose of 4mg/kg 30 minutes prior to cycling negated this effect. The conclusion of this study is that patients who do exercise to lower their IOP should avoid taking caffeine prior. Eighteen participants took part in the study. They exercised three times over three days; the first time to assess suitability and maximum power. The second and third times were placebo or caffeine. They exercised over 30 minutes with a 10 minute recovery at the end. IOP was taken using iCare. The study methodology seems sound. However, any IOP reduction was minimal barely changing from baseline. There were no glaucoma patients included and the average age of participants was 23.3 years. The extent that exercise influences overall IOP in glaucoma patients seems short-lived.

Effects of caffeine consumption on intraocular pressure during low‐intensity endurance exercise: A placebo‐controlled, double‐blind, balanced crossover study.
Vera J, Redondo B, Bardón A, et al.
CLINICAL & EXPERIMENTAL OPHTHALMOLOGY
2020;48:602-9.