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Effects of caffeine intake on visual performance of the eye among normal healthy adults

8 May 2018


Purpose: The purpose of this study is to examine the effects of caffeine on visual performance of the eye among normal healthy adults.

Methods: This two-visit randomized placebo-controlled crossover study included 49 normal healthy adults aged 18 years and above who received either 200mg of caffeine or placebo capsules. Choroidal thickness, tear break-up time, accommodative power, pupil size and reading performance were assessed at baseline, 1 hour and 2 hours.

Results:Consumption of caffeine showed an increased effect on reading rate (p < 0.05), average span of recognition and tear break up time (p=0.05) at 1 hour. There was no significant difference seen between the caffeine and placebo group in choroidal thickness (p=0.547), pupil size (p=0.137) and accommodative power (p=0.860). All the aforementioned metrics were not significant at 2 hours. Average span of recognition has a good correlation (r=0.855, p < 0.01) with reading rate that was significant at 1 hour among the caffeine group.

Conclusion: Caffeine consumption has some effect on visual performance of the eye by increasing reading rate and tear film quality. This transient effect peaks at the 1 hour mark and can potentially help an individual have better quality of vision to improve their visual performance for near tasks.


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