Does Coffee Cause Blindness?

crazy by Editorial Staff | Updated on April 26th, 2023

Have you ever heard the rumor that coffee can cause blindness? It’s an old wives’ tale that has been around for decades, but what is the truth behind this myth?

In this blog post, we will explore whether or not there is any scientific evidence to support this claim. Read on to find out more!

What is glaucoma?

Studies show that glaucoma is an eye condition that causes damage to the optic nerve, often from increased pressure from a buildup of fluid inside the eye. It can cause permanent vision loss or even blindness if left untreated. 

Exfoliation glaucoma is a specific type of glaucoma in which fluid buildup is caused by the release of microscopic fibers from the lens capsule. 

High caffeine consumption and increased risk of blinding eye disease

Recent studies have shown that consuming high amounts of daily caffeine may increase the risk of glaucoma more than three-fold for those with certain genetic risk factors. 

Caffeine and blood pressure

Studies have found caffeine to raise both systolic and diastolic blood pressure. Coffee and other caffeinated beverages have been associated with a slight increase in blood pressure, which can be more pronounced in people who are caffeine sensitive or have a hereditary predisposition to hypertension.

Caffeine and blood sugar levels

Caffeine can affect blood sugar levels in the short and long term. Studies have shown that regular, high caffeine consumption over a four-week period can impair insulin sensitivity in people with type 2 diabetes. 

Caffeine triggers a hormonal response in our bodies and can cause a spike in blood sugar levels. It appears to impair glucose metabolism and insulin response in the short term, but long-term coffee consumption may improve glucose metabolism and insulin response. 

Homocysteine, blood vessels, and eye health

Research suggests that caffeinated coffee consumption may increase homocysteine levels, an amino acid found in the human body. 

High levels of homocysteine can cause damage to blood vessels and other eye structures, leading to vision loss or blindness. It is important to be mindful of caffeine consumption and practice moderation when it comes to drinking coffee.

Caffeine and increase in intraocular pressure

Caffeine can impact your eyes’ intraocular pressure (IOP), so it is important to be mindful of your caffeine intake if you risk developing glaucoma. 

A study found that one cup of caffeinated coffee (182 mg caffeine) statistically increases, but likely does not clinically impact, IOP and OPP in those without glaucoma or ocular hypertension. However, it is important to note that this effect may be enhanced with repeated exposure to caffeine. 

Thus, it is recommended that those with normotensive glaucoma or ocular hypertension limit their intake of caffeinated beverages (>/=180 mg caffeine). 

Tips for managing vision loss

It’s important to take steps to protect your vision and prevent vision loss related to glaucoma and other causes. 

Manage diabetes to reduce the risk of vision loss

Managing diabetes is essential for reducing the risk of vision loss. Diabetes can cause serious eye damage, leading to conditions like diabetic retinopathy, which is the leading cause of blindness in adults aged 20–74. 

To help prevent this, people with diabetes should maintain good blood sugar control and check their blood pressure and cholesterol levels.

Wear sunglasses and hats to protect your eyes from UV rays

Wearing sunglasses and hats are essential in protecting your eyes from the sun’s harmful UV rays. People who wear sunglasses and wide-brimmed hats have a lower risk of developing cataracts, glaucoma, macular degeneration, and other vision-threatening conditions. 

Additionally, it is important to remember that the wrong pair of sunglasses can do more harm than not wearing sunglasses at all. Thus, choosing a pair properly designed with quality lenses and frames is important to protect your eyes from UV rays. 

Visit an eye doctor regularly for check-ups and treatments

By scheduling an appointment with an ophthalmologist, they can detect any changes in intraocular pressure that high levels of caffeine or other factors might cause. 

Patients can also receive advice on monitoring their blood pressure and blood sugar levels, as these can affect their eyes’ health.

Alternatives to caffeine

Several options are available if you’re looking for a healthier alternative to caffeine. 

Green tea

Green tea has been researched for its potential health benefits and is one of the areas where it may be beneficial in eye health. Studies have suggested that green tea could help reduce the risk of developing glaucoma. 

A network meta-analysis also showed that green tea may reduce fasting blood glucose levels compared with a no-tea control group. 

Additionally, green tea is a “super-antioxidant” that can benefit the entire body, including the eyes. 

Herbal tea

Herbal teas are naturally caffeine-free and have a variety of health benefits. They are known to contain polyphenols, which are powerful antioxidants that protect against vision loss and can help manage diabetes. 

Herbal teas can also reduce blood pressure, improve alertness and thinking skills, and help regulate blood sugar levels. It’s important to note that herbal teas have varying levels of caffeine, so it’s important to read the labels carefully before purchasing. 

Decaffeinated coffee

Decaffeinated coffee provides an alternative for those who enjoy coffee’s flavor without caffeine’s effects. In some cases, decaffeinated coffee may help reduce the risk of glaucoma and vision loss. 

Additionally, certain compounds within decaffeinated coffee, like homocysteine, can benefit blood vessels and eye health.

Yerba mate

Yerba mate is a popular alternative to coffee and other caffeinated beverages. It is made from the leaves of the Ilex paraguariensis plant and contains around 80 mg of caffeine per cup. This is comparable to a cup of coffee but with added benefits due to its phytochemical interactions. 

Additionally, some yerba mate enthusiasts believe mateine, one of caffeine’s alternative names, is a unique stimulant found only in yerba mate. 


In conclusion, the relationship between caffeine intake and intraocular pressure (IOP) and ocular perfusion pressure (OPP) is complex and not fully understood. While evidence suggests that high doses of caffeine may increase IOP and decrease OPP, especially in those with glaucoma or ocular hypertension, the clinical significance of these effects remains unclear.

It is important for individuals with elevated risk for these conditions to limit their intake of caffeinated beverages, particularly those containing 180 mg or more of caffeine. Further research is needed to fully understand the mechanisms and implications of caffeine on eye health.

Disclaimer: This article is for informational purposes only and is not a substitute for professional medical advice or treatment. Consult a healthcare professional for medical concerns. The author and publisher are not liable for any actions taken based on this article.

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Disclosure: No compensation or free products were received in exchange for writing this review.


Editorial Staff

The editorial staff at Crazy Coffee Crave is a team of coffee enthusiasts & Baristas who enjoy the one thing we all think about as soon as we get up in the morning. Trusted by thousands of readers worldwide.