According to the 2017 National Coffee Drinking Trends report, released at the Coffee Association’s conference in Austin, TX, 62% of the more than 3,000 surveyed participants said that they were daily coffee drinkers— an increase from 57% of respondents in 2016.
The U.S. population is drinking more coffee than ever. So, what is all this caffeine doing to our eyes? Let’s take a look at the findings of some recent studies regarding a few major eye diseases and vision conditions.
According to a study published in the journal “Investigative Ophthalmology and Visual Science”, consuming more than 3 cups of coffee per day, compared to no coffee at all, led to an increased risk for a specific type of Glaucoma called Pseudoexfoliation Glaucoma.
An analysis of several studies by Li, M et al, however, demonstrated a correlation between caffeine consumption and increased eye pressure only in people who were already diagnosed with Glaucoma or Ocular Hypertension. It showed no effect on people without the disease.
A separate study, published by Dove Press, tested the effects of caffeine on the eyes via the administration of caffeinated eye drops, three times per day for one week, to volunteers with Glaucoma or Ocular Hypertension. The study showed no change in eye pressure in any participant.
Based on these studies, while there may be a slight correlation pointing to an increase in Glaucoma risk for people consuming 3 or more cups of coffee per day, there is no conclusive evidence of significantly increased risk.
Chlorogenic Acid (CLA), an ingredient found in coffee at a concentration 8x higher than in caffeine alone, may help to ward off degenerative retinal diseases like age-related Macular Degeneration. A study done at Cornell University showed that mice retinas displayed no oxidative damage when treated with a chemical that created oxidative stress and free radicals if their retinas were first treated with CLA.
A study published in the journal Ophthalmology looked at the effects of caffeine intake on the volume of tears on the surface of the eye. In the study, subjects were given capsules with either placebo or caffeine and then had their tear volume measured. The results showed that there was increased tear production in the participants who were given the caffeine capsules vs the placebo. This could indicate that coffee consumption might have a beneficial effect on Dry Eye symptoms.
For years eye doctors have been taught that one of the primary triggers for a feeling of twitching in your eyelid is too much caffeine intake (along with stress, lack of sleep and dry eyes). I have been unable to find any substantial evidence to support this teaching, so I’m going to have to leave this one as maybe, maybe not.
The End Result
Overall, there seems to be little evidence pointing one way or the other on the effects of coffee consumption on your eyes. There may be a slight positive correlation between drinking a lot of coffee (more than 3 cups per day) and an increased risk of glaucoma, but it might also decrease your risk of macular degeneration or dry eyes.
Since there is no overwhelming positive or negative data, our recommendation is to, as with most things, enjoy your coffee in moderation.