Medically reviewed by< Carla Ericksen, O.D.

The number one symptom related to sight that sends people to their primary health care provider? Blurry vision, according to the Cleveland Clinic. But what is it exactly? And more importantly, what causes it?

“There can be hundreds of causes of blurry vision,” says Carla Ericksen, O.D., an optometrist with America’s Best Contacts & Eyeglasses in Lincoln, Nebraska.

Read on to see what could be triggering your blurry vision, plus how to get your crystal clear eyesight back.

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What is blurry vision?

To understand blurry vision, it helps to understand how your eyes and brain work together to see. “Light travels through multiple layers of tissues and cells as it passes to reach your retina,” says Dr. Ericksen. The retina makes sense of light and images and relays this information to your brain.

If something disrupts the light as it travels — such as the shape of your eye or leaky veins — it can cause the light to scatter before it reaches your retina. The result is blurred vision. At its most basic, blurry vision just means you can’t see things sharply.

Blurry vision can come on suddenly or get worse over time. If it comes on suddenly and you have a pain in your eye or lose sight in one or both eyes, that’s an emergency. Call 911 or head to your closest emergency room, as blur combined with vision loss could signal a stroke, a concussion, or a dangerous rise in blood pressure.

But most cases of blurry vision come on gradually, sometimes without you even noticing right away. You may also find yourself squinting or blinking more often to get rid of the blur, says Dr. Ericksen.

What are signs of blurry vision?

“Everybody describes blur differently,” says Dr. Ericksen. “Some people will describe it as fuzzy. Some will say that colors are melding together or that they have a harder time reading or recognizing someone.”

Another sign? Blinking more often than usual, says Dr. Ericksen.

Does blurry vision mean I need new glasses?

Maybe. Two common causes of blurry vision are changes to your eyesight, like becoming more nearsighted or farsighted. Those refractive errors could be corrected by new eyeglasses.

But that’s not true for all cases, says Dr. Ericksen. If an underlying eye condition is behind your blur, a stronger prescription won’t necessarily help you see better. In fact, “too much power can cause headaches and light sensitivity if prescribed incorrectly,” she says.

One tip-off? If you’re older than 26 and your eyeglass prescription is still changing often, it may mean that your health or lifestyle is affecting your eyesight, says Dr. Ericksen. Keep reading to learn about the many blurry vision culprits, all of which can make your world look out of focus.

What causes blurry vision?

When you discuss your symptoms with your eye doctor, they’ll look at these common issues:

Vision changes. Changes to your eyesight are the leading cause of blurry vision. Luckily, these refractive errors can be easily corrected with eyeglasses or contacts. Here are some of the vision changes that could be behind your blur:

• Myopia: (nearsightedness): When the shape of your eye is too long, light doesn’t reach the retina, says Dr. Ericksen. That causes faraway objects to appear blurred.
• Hyperopia[link to HUB, which posts 9/13]: (farsightedness): When the eye is too short, light goes past the retina. So, it’s tougher to read or see things that are nearby.
• Presbyopia: As people age, the lens that lets light through to the retina becomes stiffer with age. A less flexible lens makes it harder to focus on close-up things, such as a recipe or text message. It’s a natural part of aging that starts around age 45.
• Astigmatism: When the cornea is a different shape than normal, the light entering your eye scatters before it can hit the retina, says Dr. Ericksen. That can make things look wavy, or you might see halos or starbursts.

Focusing issues. Sometimes it’s the way the eyes work together that’s causing things to appear blurry. These types of issues include:

• Accommodative dysfunction. It’s when your eyesight becomes blurry as you shift your focus from one near object to another faraway object, or vice versa — for example, looking from your laptop screen to a car out the window. The blurriness might not last long, but it can cause headaches and eyestrain.
• Binocular dysfunction. This means your eyes aren’t working well together, says Dr. Ericksen. You might see shadows around images or words might jump around on the page, she notes. This can happen after a concussion or even a viral illness, she adds.

Dry eye. Dry eye affects millions of Americans every year, according to the National Eye Institute. If you’re one of them, your eyes might feel like you’ve got grit in them, or they may sting because you’re not producing enough tears.

Another sign of dry eyes? “People will notice an increase in blur at all ranges that may fluctuate or be described as foggy,” says Dr. Ericksen.

Dry eye syndrome, or chronic dry eye, is becoming more common. One possible cause is working at a screen and not blinking enough, says Dr. Ericksen. Other culprits include age (people over 50 tend to develop it), poor sleep, and some medications, says Dr. Ericksen.

Eye strain. People use their near vision a lot more now than they used to, notes Dr. Ericksen, particularly when they focus on a computer or device for long periods of time. “We have a very visually demanding world,” she adds. That resulting strain on your eyes can make it harder to focus, so things look blurrier.

Medication side effects. Some medications can affect your eyesight. Certain antidepressants and antianxiety medications can reduce focusing ability and lead to people needing reading glasses when they didn’t need them before, says Dr. Ericksen. So too can antihistamines, she adds. Those can affect focus and trigger dry eyes.

Medications for high blood pressure can also affect your eye muscles and cause double vision, which might make things appear out of focus. “Because the eye muscles are so small, they can be affected by medications first,” says Dr. Ericksen.

Since there are multiple drugs that can cause blurry vision, talk to the pharmacist to check if the one you’re taking has that side effect, Dr. Ericksen recommends.

Hormones. Hormones change during pregnancy and menopause. And taking birth control pills can cause levels of estrogen and progesterone to fluctuate, which affects your eyes. Even stress, which releases the hormone cortisol, can mess with your vision.

Hormone shifts can change the shape or thickness of your cornea, which affects the way light travels through it. They can also affect your tear glands, so your eyes become dryer. Both trigger blurry vision.

Usually, your blurry vision clears up when hormone levels stabilize. But if your eyesight is still fuzzy, it’s worth a trip to the eye doctor to rule out something more serious, such as diabetes.

Swelling. “Many people are unaware that swelling of the cornea, the lens, retina, or nerve can all cause blur,” says Dr. Ericksen. Many things trigger this type of swelling, she adds, including:

• Getting something in your eye, such as dirt or an eyelash
• A trauma, such as a head injury or eye injury
• A virus that spikes inflammation throughout the body, such as the flu

When your optic nerve becomes inflamed, that’s called optic neuritis. It can be caused by viruses, bacteria, or autoimmune disorders such as multiple sclerosis.

Eye conditions. Some eye conditions can cause foggy, hazy, or blurry vision. You might not notice it at first, as it happens gradually.

The most common ones include:

• Glaucoma, a group of diseases that damage the optic nerve, usually from a buildup of fluid in the eye. You gradually lose your side, or peripheral, vision. But if your blurry vision comes on suddenly, you could have angle-closure glaucoma, which requires emergency treatment.
• Cataracts, which affect adults over 60 as proteins in the eye’s lenses clump together, leading to cloudy vision.
• Macular degeneration, another age-related disease that affects a part of the retina. The signs include seeing wavy lines or blurs when looking at things straight-ahead.
• Diabetic retinopathy, which is a complication of diabetes and affects blood vessels in the retina. If you have diabetic retinopathy, the blur might come and go.

There are other chronic conditions that can cause blurry vision, including high blood pressure. That’s why getting regular eye exams is so important, since early detection — and action — leads to the best outcomes.

“There are around 300 different diseases that can be seen just through the eye,” says Dr. Ericksen. “The eye is the only place where optometrists can see the structure of the arteries and veins and the health of the nerve without making an incision.”

How will my eye doctor diagnose blurry vision?

“We can kind of tell by how you describe your blur what part of the eye may be causing the problem,” says Dr. Ericksen.

But because they still need to figure out the cause, you’ll get a comprehensive eye exam, she adds. Your optometrist will:

• Test how sharp your vision is at 16 inches and at 20 feet.
• Measure your depth perception, “which tells us how well your eyes are working together and how well you judge how far away something is,” says Dr. Ericksen.
• Test eye movement, or how well you track objects in motion.
• Look at the overall health of your eye, to check for conditions like diabetes or glaucoma.

They may also recommend a visual field test, which is not part of a regular eye exam. This assessment lets your eye doctor see how the light travels through each part of your eye and look at the whole structure of your eye.

“All along the way, we’re taking information and that tells us where to look then in the eye,” says Dr. Ericksen.

How is blurry vision treated?

Treatment for blurry vision depends on the cause, says Dr. Ericksen. “The goal is help relieve blur and make images sharper for people to see at all distances.”

Your optometrist may recommend some of the following treatments:

• Lubricating eye drops, or artificial tears, to soothe dry eyes.
• Medicated drops can reduce the swelling in the cornea causing astigmatism, as well as help lower the pressure in the eye that’s causing glaucoma.
• New eyeglasses or contact lenses, to correct refractive errors such as myopia.
• Vision therapy, to help with things such as accommodative or binocular dysfunction.
• Prism lenses, to fix double vision and eyestrain.
• Surgery for cataracts and sometimes glaucoma.

Can you prevent blurry vision?

Most of the time, yes. And it’s as simple as going to the eye doctor for a yearly eye exam.

Dr. Ericksen goes even further. “I https://www.americasbest.com/blog/article/caring-for-your-eyes/6-things-eye-exam-can-do-you-even-if-you-have-2020-visionhttps://www.americasbest.com/blog/article/caring-for-your-eyes/6-things-eye-exam-can-do-you-even-if-you-have-2020-vision before people start any new activities, like a new job, hobby or class,” she says. That’s another way to catch a change in your vision before it becomes a problem.

There are also lifestyle changes that can go a long way toward keeping your eyes healthy. “Your cornea is like a windshield,” says Dr. Ericksen. “We want to keep it nice and clear and healthy. The healthier the cells in your eyes are, the better your vision.”

Here’s what she recommends to her patients:

• Eat plenty of fresh fruits and vegetables, which are rich in antioxidants that help your eyes stay healthy.
• Get good sleep. “It allows your eyes a chance to reboot,” explains Dr. Ericksen.
• Give your eyes a break when you work on the computer or look at your devices. Try the 20-20-20 rule: Look away from your screen every 20 minutes for 20 seconds to focus on something 20 feet away.
• For families with a history of myopia, make sure the kids are playing outdoors for a couple of hours a day, as sunlight may slow down the rate of progression of myopia, says Dr. Ericksen.
• Don’t smoke cigarettes, or take steps to quit if you do smoke. “That is good for all parts of your body, but especially your eyes,” says Dr. Ericksen. Tobacco use raises your risk for certain eye conditions and interferes with the comfort of your vision.

See our sources:
Blurred vision overview: Cleveland Clinic
Dry eye overview: National Eye Institute
>How hormones affect vision: American Academy of Ophthalmology
Pregnancy and blurry vision: Cleveland Clinic
Optic neuritis overview: MedlinePlus
Glaucoma overview: National Eye Institute
Diabetic retinopathy overview: National Eye Institute