For many Americans, drinking coffee is the best way to start the morning. The caffeine is known to stimulate the brain and keep you alert and awake – something that’s definitely needed on most mornings! And while there are many health benefits to coffee, there are some risks as well. Over-consumption of coffee can have a negative effect on your eye health, both in the short- and long-term.

Let’s learn more about how your caffeine intake might be impacting your vision and how much caffeine is considered safe.

Short-Term Effects of Caffeine on the Eyes

While we focus mainly on coffee because this is where most Americans get their caffeine intake from, don’t forget that many other beverages and some chocolates contain caffeine. When you combine them with coffee, it’s possible that you’re getting more caffeine than you should.

Most ophthalmologist doctors in New York agree that caffeine in moderation is fine. But an excessive amount of coffee or caffeinated beverages can suddenly increase blood sugar levels, leading to blurred vision or sudden spasms of the eyelids. Drinking too much caffeine can also cause the eyes to tingle and burn, a sensation that’s certainly not comfortable, especially during your workday.

Long-Term Effects of Caffeine on the Eyes

Research shows that there is a direct correlation between people who drink three or more cups of coffee per day and their chance for developing glaucoma. This eye disease is characterized by high pressure on the optic nerve, which can reduce the field of vision.

There are a couple of theories for why this may happen. First, an accumulation of deposits form on the eyes and can increase the risk for glaucoma. Second, caffeinated beverages increase blood pressure and pressure in the eyes. We still have more to understand about this study, but it is something to think about if you’re a big coffee drinker.

How Much Caffeine is Safe to Drink?

According to Mayo Clinic, up to 400 milligrams of caffeine per day appears to be safe for most healthy adults. Depending on the brand and type of coffee you’re drinking, this could allow you up to four cups of coffee (or two energy drinks or 10 cans of cola) a day.

If you’re concerned about your risk for developing glaucoma, or if you’re already experiencing symptoms like dry eye, muscle spasms or blurred vision, cut back on the caffeine and see if your symptoms improve. If they don’t, schedule an appointment with your eye specialist to find out what is impacting your vision.