Waking up with blurry vision in the morning is a common occurrence, though if it’s consistent, it may have you curious as to the cause. Rest assured, temporary blurry vision in the morning is usually harmless and can be attributed to the environment and several ordinary habits.

While it doesn’t usually take long for your vision to adjust back to normal, morning blurriness can be caused by eye allergies, sleeping in contact lenses or even certain medications.

Why you may be waking up with blurry vision

If you’ve woken up with blurry vision in one or both eyes, chances are one of the following sources is to blame. Fortunately, each one is fairly simple to avoid or manage.

Eye allergies

Eyes typically react to allergens by watering, itching, swelling or drying out. Dry eyes can cause blurred vision, especially when it’s first thing in the morning.

If you only experience eye allergy symptoms in the morning, the allergens may be in your room. Common household allergens include dust mites, pet dander and certain laundry detergents.

Sleeping with a fan on

Whether it’s the fan on your bedside stand or the one on the ceiling, sleeping with it on throughout the night can wreak havoc on your eyes and skin.

Though your eyes are closed when you sleep, fans can make them dry, irritated and itchy, leading to blurred vision in the morning.

Specific medications

Many people take specific medications at bedtime, which can lead to lower tear production throughout the night. The most common medications with this side effect include cold medicine, blood pressure medicine, sleep aids and antihistamines (the active ingredient in many over-the-counter sleep aids in an antihistamine).

Unless specifically suggested otherwise by your doctor, try taking these medications at a different time of day, when you’re able to fend off dry eye symptoms with artificial tears.

Tears that have dried overnight

Your eyes are constantly producing tears — even when you’re sleeping — to keep the eyes moist, nourished and clean.

If you wake up with blurry vision, it’s possible that tears dried on the surface of your eyes while you slept. Don’t worry, blinking a few times once you’re awake should break up the buildup on your corneas and restore clear vision.

Sleeping in contact lenses

Unless you’ve been prescribed extended-wear contacts by your eye doctor, sleeping in your contact lenses is not recommended.

Wearing contacts overnight raises your risk of various eye infections and reduces the level of oxygen supplied to your eyes. The lack of oxygen dries out the eyes, resulting in blurry vision when you wake.

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Fuchs’ corneal dystrophy

Seen most commonly in women over age 50, Fuchs’ corneal dystrophy causes swelling of the corneas (the clear outer layer of the eye) during sleep. This swelling effect creates blurred vision in the morning, though it usually improves during the course of the day.

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Diabetes

Blood sugar levels associated with diabetes can cause vision fluctuations. It’s common for diabetics to wake up with blurry vision if their blood sugar is too high or too low. Blurry vision related to diabetes may be accompanied by other symptoms, including weakness or dizziness.

Sleeping on your face

Sleeping face down is not only bad for your neck and skin, it can affect your eyes as well. This sleeping position can cause floppy eyelid syndrome — a condition that diminishes the elasticity in the upper eyelid.

Floppy eyelid syndrome can result in burning eyes, tearing up and blurred vision in the mornings. Though the condition is most common among men who are overweight, it can affect anyone.

Problems with your oil glands

Meibomian glands, which are tiny oil glands around the inside of your eyelids, produce oil and water-based tears to keep the eyes moist. If the glands produce too little oil, it could result in dry eyes, not just while you sleep, but also during the day.

Dry eye testing called the Schirmer's test is available to determine whether the glands are producing enough lubrication for the eyes.

Alcohol consumption near bedtime

You may notice blurred vision the morning after a night out. In this case, blurry vision is likely caused by dry eyes, a result of being dehydrated.

Alcohol is a known dehydrator. So, even enjoying a glass of wine before bed can dry out your eyes, leading to blurry vision in the morning.

When to see an eye doctor

Blurry vision is usually temporary and does not require medical attention. However, if your blurred vision persists or has additional symptoms with it, it’s wise to see an eye doctor.

Suffering a head injury near bedtime — especially one severe enough to cause a concussion — can cause blurry vision in the morning. In this case, blurry vision may also be accompanied by other symptoms, including:

• Dizziness

• Nausea

• Headache

• Ringing in the ears

• Lack of coordination

Waking up with blurred vision can also be a sign of stroke, a life-threatening event involving a blood clot in the brain. If any of the following symptoms are detected, it’s critical that you seek medical attention immediately.

• Numbness or tingling, especially on one side of your body

• Difficulty speaking

• Headache

• Dizziness

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