Why is Your Vision Blurry?

Learn what to do when one or both eyes are cloudy

Vision changes throughout your lifetime are common — and blurry vision can have many causes. When you’re younger, your vision might change due to nearsightedness, farsightedness or astigmatism. These are easily treated with glasses, contact lenses or other methods. Children and teens who notice vision changes can get help from an optometrist.

But some acute medical conditions can lead to vision changes, too, especially sudden ones. Being aware of these conditions means you’ll know when to seek more urgent attention.

“Maintaining good eye health requires a full examination other than just getting glasses,” says William Ensor, DO, a specialist in comprehensive ophthalmology with Geisinger Healthplex State College. “It’s also about finding and treating medical conditions to prevent damage while optimizing your best quality of vision throughout your lifetime.”

So regular eye checks are smart. If your healthcare provider does diagnose an eye disease, you often have a chance to slow its progress and safeguard your vision for years to come.

What causes blurry vision?

Identifying the source is the first step in finding the right treatment for your vision changes.

Stroke

A stroke or transient ischemic attack (TIA or "mini-stroke") can cause blurry vision. This happens if the stroke affects the part of your brain involved with vision or if the stroke activity is occurring in your eye. A sudden painless loss of vision or blurring of your eyesight may be one of the first signs of this serious medical condition.

"Be especially vigilant if a vision change is accompanied by other classic stroke symptoms," says Dr. Ensor. "They include numbness, confusion, trouble with balance, severe headache, face drooping, arm weakness and speech difficulty.” If you have any of these issues, call 911.

Floaters

So-called “floaters” in your eyesight come in many varieties. Typically, these small specks in your vision are more of a nuisance than a concern, and happen with aging. However, in other settings they can signify a warning sign of serious problems occurring in your retina — the sensitive tissue lining the back of the eye that’s responsible for good vision.

“If you experience a sudden onset of many new floaters, flashes of light in the eyes and also notice a loss of vision like a curtain coming up or down, you need to be evaluated by an eye specialist in 24 hours,” says Dr. Ensor. “These signs can be concerning for a retinal tear or detachment, which, if not treated in a timely fashion, can lead to lasting vision loss.”

Floaters can also be a sign of diabetes or an inflammatory eye condition. When in doubt, call your doctor’s office.

Diabetes

Having diabetes can do damage your eyes — especially if your blood glucose is uncontrolled. If your blood sugar spikes, fluid can leak into the lens of your eye, changing your vision sharpness suddenly.

“Blurry vision can be a first sign of diabetes,” says Dr. Ensor. “If you’re an adult who has rapidly become dependent on glasses for better vision in a matter of weeks, you should have your blood glucose checked.”

Blood sugar that remains uncontrolled can damage your retinas. Because the damage happens slowly at first, you may not notice it for a long time. Regular eye exams are the only way to monitor it. Other vision changes you may notice with diabetes are:

Spots or dark shapes in your vision
Dark or empty areas in your field of view
Trouble seeing colors

Trauma

Head or eye trauma, such as from a car accident, a recent fall or a direct injury to the eye should prompt an urgent eye exam. While the shape of the bones surrounding your eye are designed to protect it, concussive or direct forces can cause significant vision problems. Have your eyes evaluated by an ophthalmologist if you notice changes in your eyesight after an injury.

“If you seek medical care and treatment early, you give your eyes the best chance for recovery in these situations,” says Dr. Ensor.

Eye infection

Viruses, bacteria or fungi can cause infections that lead to blurry or hazy vision in 1 or both eyes. Some eye infections are extremely contagious. You’ll probably have some or all of the following symptoms:

Sensitivity to light
Pink or red appearance
Mucus or crust when you wake up
Swollen eyelids
More tears than normal
Burning sensation or pain

“Any sudden, severe, red painful eye should be evaluated to rule out infection or other serious eye conditions,” says Dr. Ensor. “Schedule an urgent visit if you wear contact lenses, as this is a major risk factor for an eye infection, especially if your contact lens hygiene isn’t adequate.”

Pregnancy

Blurry vision is common when you’re pregnant, particularly in the later trimesters of pregnancy. Hormonal changes can lead to dry eye or changes in the shape of the cornea, causing your vision to be out of focus. You may see an increase in floaters. But vision changes can also be a sign of pre-eclampsia, a life-threatening condition. Contact your health provider immediately or go to the emergency room if you suddenly:

See flashing lights or auras
Have light sensitivity
Have blurry vision or see spots

Other signs of preeclampsia include high blood pressure, headaches, stomach pain, nausea, swelling in the hands and face and gaining more than 5 pounds in a week.

Cataracts

When the lenses in your eyes get cloudy, often with age, they’re known as cataracts. The lens sits just behind your pupil and channels light into your retina. When the lens is cloudy, it’s like looking through a filmy, dirty window. Your vision might be blurry or hazy, and colors might not be as vibrant. You may have a hard time seeing — especially at night, with bothersome glare and halos.

“Cataract surgery can replace the blurry lens with a new, artificial lens in an outpatient setting. This is done commonly to improve your vision,” says Dr. Ensor.

Migraines with aura

Migraines are more than a headache. They’re a neurological condition causing symptoms across the body — including the eyes. A quarter to a third of people who get migraines have vision changes called an “aura.” This is not an emergency. It’s thought to happen because electrical and chemical signals go across your brain and start the migraine, but they also disrupt the visual centers in your brain.

You may notice:

A spot in your vision
A shimmering or sparkly area
Flashes of light, zigzag patterns or blind spots

They usually last 20 to 60 minutes and may or may not be followed by a headache. “If this is your first aura, it lasts longer than an hour or you’re pregnant, contact your healthcare provider,” says Dr. Ensor.

Dry eye

Your tears protect your eyes by keeping them moist. They’re made from oil, mucus, water, salt and substances that fight infection. In dry climates and as you age, your eyes make fewer tears and of less quality. This causes a condition called dry eye, especially common in people over age 40. Common symptoms include blurriness or change in vision. These changes tend to fluctuate throughout the day and are not constant. Other symptoms include:

Tearing
Burning or stinging
Feeling like there’s something in your eye
Stringy mucus, especially when you wake up in the morning
Light sensitivity
Difficulty driving at night
Difficulty wearing contact lenses

You can treat dry eye with over-the-counter lubrication drops from reputable brands. Spending less time on screens or wearing contacts will help, too. Be sure to tell your eyecare provider about your dry eye symptoms in case you need other treatment.

Could blurry vision be an emergency?

Sudden vision changes should always raise a red flag. Seek care right away if you have an abrupt change in your vision, especially if you’ve had recent trauma, are pregnant or have other symptoms. Certain conditions require evaluation by an ophthalmologist — and in some cases, a trip to the ER.

"Any sudden change in your eyesight, especially an unusual change, should be considered urgent," says Dr. Ensor. "Once you’ve identified the cause, you and your doctor can work together to treat the underlying issue creating your vision problems. This could be a simple, one-time visit or it could lead to a diagnosis that will need monitoring for the rest of your life."

Either way, you’ll have a better outlook on your health.