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For many people, a cup of coffee in the morning is a must-have. In fact, some say they don’t even open their eyes until they have that first sip. However, there can be too much of a good thing. Excessive caffeine can negatively impact your vision in the short term, and over time, can even cause more serious damage. Keeping your caffeine intake down can be an important part of your overall eye care strategy.

Common Eye Conditions after Short-Term Caffeine Use:

When you drink too much coffee or overindulge in caffeinated energy drinks, you may experience sudden fluctuations in your blood sugar levels. This quickly translates into blurred vision, along with nausea, changes in appetite and rapid heart rate. Too much caffeine is also directly linked to involuntary twitches in the eyes or eyelids, which is known as myokymia. Though this condition isn’t painful or dangerous, it can be disruptive to daily activities.

Effects of Caffeine on Vision

Some individuals find that consuming large amounts of caffeine in a short period of time reduces tear production, causing dry eyes. Short-term, this condition brings some discomfort, including a burning or gritty sensation. Over time, if dry eyes are not corrected through decreased use of caffeine or medical intervention, chronic dry eyes can lead to a greater risk of eye infections, inflammation of the eyes, corneal abrasions and difficulty performing focus-intensive activities such as reading.

Eye Diseases Related to Long-Term Caffeine Use:

In addition to the temporary short-term impact on vision, there can be permanent consequences to long-term overuse of caffeine. For example, one study found that the risk of developing the degenerative eye disease glaucoma is greater in individuals who drink three or more cups of coffee per day. It causes an increase in eye pressure, which can endanger patients already suffering from glaucoma.

The research on relationships between caffeine and glaucoma is incomplete, and additional studies are needed to understand what level of consumption is safe. In the meantime, occasional caffeinated beverages are unlikely to cause long term damage, but individuals already at risk for glaucoma may wish to limit their intake.

Signs of Caffeine Overdose:

Though caffeine is found in medications, foods, and beverages that people consume on a daily basis, it should still be treated with the same caution as any other drug. Overuse does come with health risks, and in extreme cases, overdoses can be dangerous. General recommendations suggest no more than 400 milligrams (mg) of caffeine per day for healthy adults. However, you should speak with your physician for information specific to your situation. Four cups of coffee, two energy shots or ten cans of soda equal approximately 400 mg of caffeine, but bear in mind that you can unintentionally exceed this amount if you combine medication containing caffeine with caffeinated foods or drinks.

Many people suffering from caffeine overdose report seeing flashes of light. Other symptoms include trouble breathing, convulsions, dizziness, fever, increased thirst, hallucinations and rapid or irregular heartbeat. If you experience these symptoms, seek emergency care immediately.

Cutting caffeine out of diets completely is a deal-breaker for coffee connoisseurs. Fortunately, for most people, this drastic step is not necessary for keeping your eyes healthy. The most common eye problems related to caffeine are brought on by excessive use – not drinking a cup or two of coffee to start your day. However, if you experience changes in your vision, it is important make an appointment with your ophthalmologist right away.

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  1. Paul Andrews says:

    I’m a coffee freak and this information is pretty interesting for me. Thank you so much for sharing this!

  2. garland graham says:

    drinking carrot juice is helpful in obtaining better vision. TRUE OR FALSE? IF IT S NOT. THEN WHAT FOOD OR DRINK IS APPROPIATE FOR BETTER VISION. THANK YOU.

    • Sandy says:

      It’s supposedly false, but since I was diagnosed with diabetes, I have been snacking on carrots quite often and my vision has improved. It’s still bad,but not as bad as it was.

  3. Peter Abimbola says:

    For sometimes now like two years plus have been drinking coffee with other beverages. I am diabetic but my wife died and the stress of taking care of my son and the church wear me down that I lost some weight.
    I have been on antibiotics, multivitamins, blood purifier and diabetes drugs but my vision got blurred can’t see clearly but still driving.

  4. Steve Wilson says:

    I’m reading this (or trying, though blurred vision and bright spots) after switching to a new brand of coffee that, turns out, is exponentially stronger than my old brand. One cup of this new stuff and I’m non-mission capable at a job that requires looking at spreadsheets and data all day. I can’t read right now, so …Is this article legit? Maybe. I’ll tell you after I stop seeing all 144 hertz in my monitor’s refresh rate, my co-worker’s skeleton’s and the future,

    • Hands down the funniest comment we’ve received to date. Although it is unfortunate that you’re experiencing blurred vision and bright spots … that part isn’t funny at all. So sorry we didn’t see your note sooner, but hopefully the caffeine has worn off by now. If you’re still having vision trouble, please call our office … viewing the world at 144 hertz seems like a bad idea.

  5. Karen says:

    After drinking coffee in the morning my wife gets a pain in her left eye & she also experiences a dullness in her eye. Is this linked to coffee intake or is there something else going on?

  6. Ken says:

    Recently diagnosed with borderline Diabetes, I have been enjoying eating my way through the Keto Diet recipes and losing weight has been easy and enjoyable. One of the suggested breakfasts is a strong, iced coffee with cream. Yippee I shouted and also started to drink refreshing diet drinks since the Keto philosophy is minimum carbs and sugar but no problem with protein and fats.
    I have just realised that the extra coffee and Diet Cola drinks have signalled to me that I have an intolerance to so much Caffeine.
    Within minutes, my vision is disturbed by floating clear bubbles and I become disorientated. Thankfully it only lasts about 15 minutes but I am now unfortunately looking for other beverages…I can’t even replace them with high-carb beer.

    • Vika says:

      I always had unpleasant scenario with consuption of caffeine but never had such desperate episode as drinking a can of Red Bull. My eyes got so dry and I was wearing contacts and I was lubricating constantly with saline solution. Well after remove the lens that was hard to remove my eyes got completely smokey vision. I was in shock when I realized. After that I closed my eyes and rested and so my vision was restored after a long sleep. But I cant deny the caffeine made my whole body felt like dry and desperate for water

  7. laurel Neth says:

    I have, over the last month or two, cut my caffeine by 1/2 by only using 1/2 the amount of grounds in my coffee maker. I usually have two weak cups in the morning and this morning I had my 2 cups, went shopping and on the way home got a Starbucks coffee (delicious!). About 1 hour after drinking the Starbucks, I noticed my vision was quite a bit blurrier than it had been earlier. Curious whether drinking caffeinated coffee could cause blurry vision, I Googled that question. Yes! It is possible. So now I will cut the caffeine and drink non-caffeinated coffees. Glad to have this information.

  8. Marjorie Miller says:

    I have always had blurred vision after drinking coffee. Yesterday, I tried coffee from one of those pod type coffee makers. Soon after having jut one cup, I felt light headed and a little off balance while on my feet. Several hours later, I suddenly lost all focus in my right eye while walking through a nursery. If you have ever had one corrective lens of your glasses fall out while wearing them, it was similar to that experience but worse. It was horrible, had to sit down, could not focus. I thought I was having a stroke! No more of that coffee for me! As a retired nurse practitioner, I would love to learn the physiology behind this.

  9. Travis says:

    Within 30 minutes of drinking coffee I get blurred vision. This is been going on for 15 years. I seldom drink coffee of course, but every once in awhile I’ll have a cup and sure enough here comes the blurred vision. So I basically given up coffee and other types of caffeine such as green tea. I can drink decaf anything and not have the problem. Doctors can’t figure it out.

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