New study links caffeinated coffee to vision loss

A new study suggests caffeinated coffee drinkers should limit their intake to reduce their chances of developing vision loss or blindness. According to a scientific paper in Investigative Ophthalmology & Visual Science, heavy caffeinated coffee consumption is associated with an increased risk of developing exfoliation glaucoma, the leading cause of secondary glaucoma worldwide. The study, The Relation between Caffeine and Coffee Consumption and Exfoliation Glaucoma or Glaucoma Suspect: A Prospective Study in Two Cohorts, is the first to examine the link between caffeinated coffee and exfoliation glaucoma in a U.S. -based population.

"Scandinavian populations have the highest frequencies of exfoliation syndrome and glaucoma," said author, Jae Hee Kang, ScD, of Channing Division of Network Medicine at Brigham and Women's Hospital in Boston, Mass. "Because Scandinavian populations also have the highest consumption of caffeinated coffee in the world, and our research group has previously found that greater caffeinated coffee intake was associated with increased risk of primary open-angle glaucoma, we conducted this study to evaluate whether the risk of exfoliation glaucoma or glaucoma suspect may be different by coffee consumption."

The study was composed of two cohorts: 78,977 women from the Nurses' Health Study (NHS) and 41,202 men from the Health Professionals Follow-up Study (HPFS) who were at least 40 years of age, did not have glaucoma and reported undergoing eye examinations from 1980 (for NHS participants) and 1986 (for HPFS participants) to 2008. The research team used questionnaires to obtain and validate the consumption of beverages containing caffeine and reviewed medical records to determine incident cases of exfoliation glaucoma, which contributes to elevated pressure sufficient enough to damage the optic nerve, or exfoliation glaucoma suspect that have milder or only suspect optic nerve damage.

A meta-analysis of the two cohorts showed that, compared to abstainers, participants who drank three cups or more of caffeinated coffee daily were at an increased risk of developing exfoliation glaucoma or glaucoma suspect. The researchers did not find associations with consumption of other caffeinated products, such as soda, tea, chocolate or decaffeinated coffee. The results also showed that women with a family history of glaucoma were at an increased risk.

Kang, along with his colleagues, report that this study represents a much needed effort to better understand the causes of exfoliation glaucoma, which are largely unknown.

"Because this is the first study to evaluate the association between caffeinated coffee and exfoliation glaucoma in a U.S. population, confirmation of these results in other populations would be needed to lend more credence to the possibility that caffeinated coffee might be a modifiable risk factor for glaucoma," said Kang. "It may also lead to research into other dietary or lifestyle factors as risk factors.