For all the coffee lovers who drink as much coffee as I do each day, this one’s for you. Recently, a press release from the Icahn School of Medicine at Mount Sinai (“Mount Sinai”) shared the results of an international study exploring the relationship between caffeine intake, intraocular pressure (IOP), and glaucoma. Currently, glaucoma is the top cause of blindness within the U.S. Through their research, researchers determined that a high caffeine intake can triple the glaucoma risk for those genetically predisposed to higher IOP. Interested in learning more? The full findings are published here in Ophthalmology.
To begin, what exactly is caffeine? According to Healthline, caffeine is:
a natural stimulant most commonly found in tea, coffee, and cacao plants. It works by stimulating the brain and central nervous system, helping you stay alert and prevent the onset of tiredness.
In the past, researchers have linked high caffeine intake with an increased risk of glaucoma in patients with a family history of glaucoma or similar conditions. Now, researchers wanted to understand how caffeine intake impacted patients with high IOP. In the past, high IOP has been considered a risk factor for glaucoma.
To begin, researchers sourced data from over 120,000 patients within the UK Biobank; the data spanned over a 4-year period. Patient ages spanned between 39-73. In addition to providing health records, patients also provided:
- DNA samples
- Vision-related information
- Note: This information was both broad (general information regarding their vision) as well as specific in some areas. For example, patients reported on a family history of ophthalmologic conditions, including glaucoma.
- Dietary information, including portion sizes and caffeinated food/beverage intakes
Approximately 3 years later, researchers sourced additional patient data. Those who participated later provided eye measurements and IOP levels. Next, researchers ran a number of analyses regarding glaucoma, caffeine, and IOP. Additionally, researchers developed an IOP genetic risk score which was given to each study participant. Ultimately, researchers found:
- Overall, high caffeine consumption was not linked to a higher risk of glaucoma or IOP.
- But while it was not linked overall, patients who were genetically predisposed to high IOP, and who also consumed a lot of caffeine, had worse IOP and more incidences of glaucoma.
- In particular, patients in this category who had over 321 mg caffeine each day (around 3 cups of coffee) had 3.9x the prevalence of glaucoma cases.
While many coffee drinkers do not want to give up their daily cup(s), researchers believe doing so could benefit these patients. In terms of quality-of-life (QOL), patients with glaucoma – or elevated IOP – can improve and protect their vision by making this change.
Glaucoma consists of a group of ophthalmologic conditions which progressively damage the optic nerve. Normally, the optic nerve, which connects the eye to the brain, transmits electric impulses from the retina to the brain. The brain then reads these impulses and interprets them as vision. As the optic nerve becomes damaged, vision is interrupted and lost. Typically, glaucoma results from pressure buildup within the eye. Glaucoma is often painless and vision loss is gradual. A comprehensive eye examination is beneficial for early diagnosis and intervention. Altogether, glaucoma most often affects those over age 60.
Symptoms vary. But common glaucoma-related symptoms include:
- Peripheral vision loss
- “Halos” around lights
- Tunnel vision
- Nausea and vomiting
- Eye redness
- Blurred vision
- Eye pain
Learn more about glaucoma.