Blurry, unclear, unfocused vision is the most common eyesight problem, and usually it isn’t anything major to worry about it. Blurriness could just be a sign that your glasses or contacts prescription needs updating. Every once in a while though, fuzzy vision signals something more serious.
Always investigate what’s causing your blurry vision. Knowing the reason behind it can be the difference between experiencing the world in all its dimensions or not. “Sight is such a valued sense, but there are still a lot of problems that fall through the cracks,” says Rajiv Shah, MD, assistant professor of ophthalmology at Wake Forest Baptist Medical Center.
Here are some of the causes of blurry eyes and what to do about them.
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You need prescription glasses
Or you need a new prescription.
Nearsightedness (myopia), farsightedness (hyperopia), and astigmatism are refractive errors and are the most common causes of blurry vision. They happen when the curve of the eye gets in the way of light focusing directly on the retina. The retina processes light rays into signals the brain can read.
In addition to being widespread, refractive errors may also be the easiest to fix. In most cases, all you need is a prescription from an optometrist or ophthalmologist for glasses or contact lenses. LASIK laser surgery can permanently change the shape of the cornea to correct the problem in some people.
Presbyopia is also a refractive error but one that strikes most people after the age of 40. It means you have trouble focusing on things that are close up, like reading material. If you find you need to hold magazines, books, and menus farther away from your face in order to read them, presbyopia could be causing your blurry vision.
As with other refractive errors, eyeglasses, contact lenses, and surgery can help you see better if you develop presbyopia. If you aren’t farsighted or nearsighted and you don’t have astigmatism, simple reading glasses from the drug store may be enough, says Dr. Shah.
If you do have one of those other refractive errors, think about switching to bifocals, trifocals, or progressive lenses.
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You caught conjunctivitis
Conjunctivitis or pink eye is usually caused by adenoviruses, pesky viruses that can cause the common cold, bronchitis, and sore throats. Although not usually serious, conjunctivitis can spread like wildfire in schools and other crowded venues. “Virus particles on surfaces can stay alive for about two weeks,” says Kim Le, MD, a pediatric ophthalmologist with the Henry Ford Health System in Detroit.
Conjunctivitis usually goes away in one to two weeks without treatment, but if you have severe symptoms, talk to your doctor about antibiotic or antiviral medications. In the meantime, try cool compresses to alleviate itchiness, warm compresses to relieve swelling, or over-the-counter eye drops to help with irritation, says Dr. Le.
Wash your sheets (especially your pillowcases) and your hands often to prevent the spread of the germs.
Contact lenses can fix your vision without encumbering your face, but if you don’t use them properly, they can also cause sight-robbing infections.
Contact lenses move across the eye every time you blink, creating micro-scratches on the surface of your eye. Infection-causing microorganisms can get caught under the lens and get into the scratches.
Sleeping with your contacts in, Dr. Le says, “is a perfect petri dish to grow those organisms and cause corneal ulcers,” open sores on the cornea that can blur vision. “Always, always take [contact lenses] out at night,” adds Dr. Shah, or toss disposable lenses at the end of the day.
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You have an eye infection
You don’t have to wear contact lenses to get eye infections that damage the cornea.
Herpes keratitis is an infection in the eye caused by the herpes virus. You can get it just by touching a cold sore on your lips then touching your eyes. Bacteria and fungi that muscle their way in after an eye injury can also cause infection.
Treatments like eye drops and medications (such as antibiotics for bacterial infections) usually help, but the best method of protection from eye infections is prevention. Your cornea will do a lot of that work for you. “The cornea is an amazing structure,” says Bibiana Reiser, MD, assistant professor of ophthalmology at the Keck School of Medicine, University of Southern California and director of cornea and glaucoma services at Children’s Hospital of Los Angeles. “It has a lot of [antibodies] that kill things directly on contact.”
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You're developing cataracts
Cataracts are one of several eye problems that come with aging. About half of all Americans have cataracts by age 75. This is when the lens in the front of the eye becomes blurry and blocks light trying to reach the retina.
Cataracts usually take time to develop and don’t cause any pain or other symptoms. Some stay small and cause few problems. Those that do grow and interfere with vision are often treated with surgery to remove the damaged lens and replace it with a clear plastic one. “That is one of the most successful surgeries in all of medicine,” Dr. Shah says.
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Glaucoma, another age-related vision condition, is caused by extra pressure in the eye, which damages the optic nerve. Like cataracts, glaucoma is usually slow to develop.
“Patients with glaucoma don’t even know it because the vision loss happens over decades,” Dr. Shah says. “There’s really no way to suspect other than regular eye evaluations.”
Once a diagnosis is made, prescription medications, laser treatment, and surgery can help.
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You have age-related macular degeneration
As you age, and especially after you pass 60, you have a higher risk of damage to the macula, an area near the center of the retina that helps you see details and objects directly in front of you. Age-related macular degeneration or AMD results in a loss of central vision, which can make everyday activities like driving and reading understandably challenging.
There is no treatment for early AMD, although high doses of certain vitamins and minerals can slow the damage in intermediate and late AMD, according to the National Eye Institute.
You can lower your risk for AMD by exercising, keeping your blood pressure and cholesterol at healthy levels, not smoking, and eating a lot of green, leafy veggies and fish.
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If you have undiagnosed type 1 or type 2 diabetes, or diabetes that has been diagnosed but is uncontrolled, you’re at risk for diabetic retinopathy. This is when damaged blood vessels leak or extra blood vessels grow in the back of the eye and start bleeding.
If you know there’s a problem, injections and laser surgery can help save your vision, but “unfortunately, this is the sneak thief of vision,” Dr. Shah says. “You can lose your vision from diabetes and not know you have diabetes.”
Controlling your blood sugar can prevent diabetic retinopathy. If you have diabetes, make sure you get regular eye exams.
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You have high blood sugar
Even before the long-term complications of diabetes settle in, high blood sugar can cause your vision to blur. “Really high sugars can lead to swelling of one’s lens,” says Dr. Shah. The swelling changes the shape of the eye and how it focuses, but the issue usually only lasts for a couple of hours or days.
If you suspect you might have high blood sugar, get checked right away. You’re at risk for type 2 diabetes if you are obese or have a family history of the disorder. Other symptoms include frequent urination and excessive thirst.
You probably know that high blood pressure can lead to stroke and heart disease. What you may not know is that it can also cause a mini stroke of the eye called vein occlusion. “These patients feel no pain,” says Dr. Shah. “They will wake up and their vision is blurry.” Blurry vision due to vein occlusion usually strikes just one eye, he adds.
Treatments for vein occlusion, including clot-busting medication, need to be given right away in order to be effective. Even then, you may lose some of your sight. To protect against vein occlusion, if you’re over 50 and have high blood pressure, Dr. Shah recommends getting regular eye exams.