A Harvard study published in Investigative Ophthalmology & Visual Science found that consumers who drink multiple cups of caffeinated coffee a day are at a higher risk of vision loss and blindness due to exfoliation glaucoma. This is one of the only studies of coffee linked to vision loss.
Do you recall the pressure test given during an annual eye examine. This is measuring the amount of fluid buildup in the eye, an indicator of glaucoma. In a normal eye, there are parts that make fluid and other parts that release it. Sometimes flakes on the lens of the eye will move and block the parts that release the fluid. The accumulated pressure is painless, but with time will damage the optic nerve, causing vision loss or blindness.
The Coffee and Vision Loss Research
The combined study, spanning 28 years, started with over 120,000 glaucoma free men and women. The 40 year old and over participants kept a daily log of the amounts of caffeinated drinks they consumed, including tea, soda, and coffee. Out of the three, only coffee showed a significant link between the disease and coffee consumption. The analysis states three or more cups of coffee a day as the benchmark for a higher risk of getting exfoliation glaucoma disease.
The Risk Factor
Doctors are not recommending a reduction in caffeinated coffee intake yet. More studies are needed to eliminate other common factors between the participants that may also contribute to the disease. However, the study suggests that genetics may play a part in the findings. Women who have a family history of glaucoma and also drink three or more cups of coffee a day are particularly at risk. The study found that women with both indicators are 66% more likely to get exfoliation glaucoma.
The Harvard study of coffee linked to vision loss has prompted more studies, but initial findings suggest that for some people, the benefits of coffee may not outweigh the negative effects of caffeinated coffee.