You’re feeling a bit blurry, your vision is going in and out of focus… you think you’re getting some double vision… Do you need new glasses? Or could it be that you just had one too many glasses – of wine?
Around the world, about 117 billion gallons of alcoholic beverages are consumed each year. In the US, beer is the drink of choice, followed by spirits and wine. However, while a tipple or two at a party is generally considered socially acceptable, a number of Americans rely on having a bottle in hand for a bit more than just to look cool or to wet their lips. In 2019, the National Survey on Drug Use and Health estimated around 14.5 million US residents were living with an alcohol addiction.
While the full effects of alcoholism are beyond the scope of this particular article, there are some interesting facts to know about the effect alcohol has on eyes.
Here are 6 ways that drinking alcohol affects your eyes:
1. Slows your pupillary reactions
The pupil is the opening in the middle of your iris, which is the colored part at the front of your eye. The iris is a muscle that can dilate the pupil (making it larger) or constrict it (making it smaller). The ability to dilate and constrict is important because it’s your eye’s reflexive way of controlling how much light gets through. Ever had a bright light suddenly shine right into your eyes? It’s not comfortable and you were probably temporarily blinded.
Alcohol consumption causes the iris muscles to relax, resulting in a dilated pupil. It also results in a slowing of your pupil reflexes, which delays your pupils’ ability to constrict in the presence of increased light. Although this may not be too much of an issue in most circumstances, it can cause driving at night to become dangerous as your eyes will not be able to react as quickly when faced with oncoming headlights.
2. Impairs your contrast sensitivity
Contrast sensitivity is the ability to discern differences in shades and patterns. For example, you need better contrast sensitivity when driving on an especially gray and rainy day, trying to pick out the silver sedan with the broken taillights in front of you through sheets of rain. Alcohol intoxication is known to cause impaired contrast sensitivity, making it all the more difficult to see properly in those difficult conditions, such as heavy rain or twilight.
3. May exacerbate dry eye disease (DED)
Different studies report conflicting outcomes on the effects of alcohol on DED. Dry eye disease, or DED, is characterized by inflammation on the surface of the eye and a compromised tear film. It often manifests as the eyes feeling dry (obviously) but is also associated with other symptoms such as gritty or burning eyes, feeling like there’s a foreign particle stuck in your eye, redness, and variable vision.
Many studies have concluded that alcohol consumption can worsen the signs and symptoms of DED. Low levels of alcohol have been detected in the tears for a short period after having a drink and are linked to increased dry eye symptoms. However, a recent study noticed that alcohol was a risk for DED only in females – and in males, alcohol intake actually had a protective effect against dry eye. One explanation for this put forth by the researchers was the effects of differences in sex hormones between men and women, particularly androgens, which are found in higher levels in men.
4. May increase your risk of cataracts
Cataracts are an opacity in the lens of the eye, which hinders the passage of light. Among other symptoms, this results in blurry, foggy vision. The only way to treat a cataract is through surgical removal.
While age-related cataracts happen to the best of us, heavy drinking has been linked to a significant increased risk in their development. In this same study, moderate alcohol consumption was found to be unrelated. Moreover, there is some emerging evidence that moderate drinking may actually help to protect against the development of a cataract requiring surgery. Coming out on top of the list of best beverages for this was red wine (fun fact: almost 25% of red wine consumption in the US is merlot). While the exact causes of age-related cataract formation are still not fully understood, many doctors believe oxidative stress to be a big contributing factor. The skin of grapes found in wine are known to be full of healthy antioxidants, which may serve to protect against the oxidative damage in the eye’s lens. One recent study reported that people who drank 6.5 standard glasses of wine per week were less likely to need cataract surgery.
5. May increase your risk of age-related macular degeneration (AMD)
In the US, age-related macular degeneration, or AMD, is the number 1 leading cause of legal blindness in those of Caucasian descent, the fifth leading cause in African Americans, and the second top cause in those of Hispanic heritage. The macula is a crucial part of the eye essential for your central vision and ability to discern fine details. AMD is a progressive, irreversible deterioration of the macula, resulting in permanent central vision loss.
Although the exact reasons why are unclear, numerous studies have found a link between alcohol consumption and the development of AMD. Having more than two standard drinks per day can increase your likelihood of early AMD by approximately 20%.
6. May increase your risk of glaucoma and elevated eye pressures
Glaucoma is an irreversible disease of the optic nerve, which is crucial for vision. In many cases, glaucoma is associated with high pressures in the eye, known as intraocular pressure (IOP). The symptoms of glaucoma are typically painless and difficult to detect until the disease is already advanced. During glaucoma, progressive optic nerve damage results in gradual and permanent loss of your peripheral vision.
The impact of drinking on IOP is not fully understood, with different studies reporting completely opposite results. Some researchers have noted that drinking alcohol is linked with higher IOP – interestingly, this association was found only in men and not women. Conversely, there are some studies that have found that alcohol can actually temporarily reduce IOP, providing some protection against glaucoma. And then there are the studies that fall somewhere in the middle, reporting that there is no relationship between drinking and IOP.
At this point in time, much more work needs to be done to really figure out whether eyecare practitioners should start recommending for or against alcohol as an accompaniment to meals. In the meantime, you can’t go wrong by following the Centers for Disease Prevention and Control drinking guidelines: you can choose not to drink, otherwise drink in moderation by limiting your daily intake to no more than 2 drinks for men or 1 drink for women. Cheers!
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