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Short-term effects of caffeine intake on binocular accommodative facility: a quantitative and qualitative analysis
Beatriz Redondo1, Jesús Vera1, George-Alex Koulieris2
1CLARO (Clinical and Laboratory Applications of Research in Optometry) Research Group, Department of Optics, Faculty of Sciences, University of Granada, Granada, Spain.
Clinical & Experimental Optometry
|June 17, 2021
Summary
Caffeine intake significantly improved the speed of visual accommodation, enhancing the number of cycles per minute. However, it did not affect the accuracy or precision of focusing for near and distant objects.
Area of Science:
- Ophthalmology and visual neuroscience.
- Human physiology and pharmacology.
Background:
- Caffeine is known to affect physiological functions.
- Its impact on visual functions, specifically accommodation, requires further investigation.
- Understanding caffeine's effects on accommodation is clinically relevant for visual performance.
Purpose of the Study:
- To evaluate the acute effects of caffeine on binocular accommodative facility.
- To assess changes in the frequency and precision of accommodation after caffeine ingestion.
Main Methods:
- A placebo-controlled, double-blind, balanced crossover study.
- Twenty university students received caffeine (4 mg/kg) or placebo.
- Binocular accommodative facility was measured using an open-field autorefractometer.
Main Results:
- Caffeine ingestion increased the number of accommodative cycles per minute (p=0.023).
- No significant effects were observed on the magnitude of accommodative change or the accuracy of accommodation.
- Perceived activation levels were slightly higher in the caffeine condition (p=0.059).
Conclusions:
- Caffeine enhances the speed (quantitative measures) of accommodative facility.
- It does not improve the accuracy or precision (qualitative measures) of accommodation.
- Caffeine's ergogenic effect may benefit visual performance in specific applied situations.
