Why Is Your Vision Blurry?
You Need Glasses
When your eyeball is shaped more like an egg than round, or your cornea or your lens isn't curved just so, light can't focus in the right spot. That can lead to seeing clearly only at certain distances (nearsighted and farsighted) and distorted vision (astigmatism). You can often correct these "refractive errors" with eyeglasses, contact lenses, or minor surgery.
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Your Eyes May Be Tired
Have you been staring at a screen or page or focusing on a task for a long time? People tend to blink less often when they're concentrating like that. And each time you blink, you're spreading tears across the surface of your eye to keep it lubricated, clean, and refreshed. You may need to remind yourself to blink more often, take breaks, and look around to prevent vision fatigue.
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You Have Diabetes
When your blood sugar isn't well-controlled, fluid may seep into the lens of your eye and make it swell. This can happen before you're diagnosed or if you're changing your treatment, like starting insulin. As your glucose level gets back to normal, the lens should, too. People with diabetes are more likely to get retinopathy and other eye problems, which your eye doctor will check for at your yearly exam.
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Your Eye Is Inflamed
Eye tissue may swell because it's been bruised or something bad was splashed in it. The herpes virus from a cold sore could move to your eye. Sleeping in your contacts, not cleaning them correctly, or not throwing them away when you should can also lead to infections. Immune system diseases that affect other parts of your body, like psoriasis, IBS, and rheumatoid arthritis, can also cause inflammation in your eye.
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Your Blood Pressure Is Low
Feeling weak and dizzy, too? Your blood pressure might be too low because you're dehydrated -- maybe from too much activity in the hot sun. Things like some medications, heart problems, poor nutrition, and hormone imbalances could also cause low blood pressure and related blurry vision.
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Fluid Is Building Up in Your Eye
That can put pressure on the optic nerve and damage it. If you're also seeing halos around lights, your eyes are very red and hurt a lot, and you feel queasy, you may have acute angle glaucoma. It develops very quickly, and you could lose your vision within a day if it's not treated. Open-angle glaucoma is more common, but it doesn't usually affect your vision at first.
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A Migraine Is Starting
About 1/4 of people who have migraines get visual auras, usually before the pain and for less than an hour. These range from shimmering zig-zag lines, sparkles, and flashes to blind spots and tunnel vision. It may seem like you're looking through water or cracked glass. (You could also have vision symptoms without or after the headache.) If it happens only in one eye, see your doctor in case it's a serious problem.
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You Have a Cataract
That's a cloudy area in the normally clear lens of the eye. They grow slowly, usually in both eyes, after age 55. But younger people, even kids, can get them, too. Colors may seem faded, it may be harder to see at night, and you may be more sensitive to glare. Special glasses and lens coatings can help you see. Surgery can replace the cloudy lens with a man-made one.
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You're Getting Older
Starting around 40, you'll notice it's harder to focus on up-close tasks like reading. The clear lens inside your eye isn't as flexible as younger people's. It's a normal part of aging. Your eye doctor can help you with reading glasses, contacts, or surgery.
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You Scratched Your Cornea
Typically, this feels like you've got a big, rough chunk in your eye. A corneal abrasion might be from an injury, but it's more likely from a bit of dust or sand. Try flushing your eye with clean water or eye wash. You can blink several times to make more tears, but don't rub or touch your eyeball. That could make it worse. See your eye doctor ASAP.
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It's Something in Your Brain
A concussion or brain injury could disrupt how information from your eyes gets processed. Depending where and how big it is, a brain tumor may affect your sight. Double vision can be one of many symptoms of brain swelling or of the membrane that surrounds it (encephalitis or meningitis), often because of infection. While it's not a symptom people usually think of, blurry vision can warn of a stroke.
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Your Retina Is Damaged
The retina (which includes your macula) is the back part of your eye where light gets focused, like a movie screen. If something happens to that surface, like swelling or tearing, the picture can be distorted or lost. Poor diet, smoking, previous eye injuries or disease, and health issues such as high blood pressure, high cholesterol, and diabetes can raise the odds of problems like macular edema and a detached retina.
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You May Have Multiple Sclerosis
Signals going from your eye to your brain have a harder time traveling through a swollen or damaged optic nerve. Doctors don't know for sure what causes optic neuritis. But about half of people who have this condition will develop multiple sclerosis within 15 years. Vision trouble is often the first symptom of MS.
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There's Trouble With Your Pregnancy
Blurry vision along with headaches, shortness of breath, or feeling like throwing up may signal a serious complication called preeclampsia. It happens when blood vessels in your placenta are too narrow and don't work right. (Higher blood pressure after 20 weeks is usually the first sign.) See your doctor right away. Without treatment, it can cause life-threatening problems. Medications and rest until you deliver can help.
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Sources Medically Reviewed on 02/09/2018 Reviewed by Arefa Cassoobhoy, MD, MPH on February 09, 2018
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SOURCES:
American Optometric Association: "Myopia (Nearsightedness)," "Hyperopia (Farsightedness)," "Astigmatism," "Dry Eye," "Glaucoma," "Cataract."
Victoria State Government, Better Health Channel: "Eyes - common problems."
Joslin Diabetes Center: "Diseases of the Eye."
American Academy of Ophthalmology: "Diabetes and Eye Health," "Herpes Keratitis," "Uveitis," "Presbyopia," "Corneal Abrasion," "Optic Neuritis."
Ophthalmology: "Risk factors for moderate and severe microbial keratitis in daily wear contact lens users."
Mayo Clinic: "Keratitis," "Low blood pressure (hypotension)," "Ocular migraine: When to seek help," "Corneal abrasion (scratch): First aid," "Brain tumor," "Retinal detachment," "Preeclampsia."
National Eye Institute: "Facts About Uveitis," "Facts About Age-Related Macular Degeneration," "Facts About Diabetic Eye Disease."
American Heart Association: "Low Blood Pressure - When Blood Pressure Is Too Low."
American Migraine Foundation: "Visual Disturbances: Related to Migraine or Not?" "Understanding Ocular Migraine."
VisionAware: "I've Had a Concussion or Traumatic Brain Injury: What Do I Ask My Eye Doctor?"
ASCO Cancer.net: "Brain Tumor: Symptoms and Signs."
National Institute of Neurological Disorders: "Meningitis and Encephalitis Fact Sheet."
Harvard Health Publishing: "Recognizing the most common warning signs of a stroke."
Archives of Neurology: " Multiple Sclerosis Risk after Optic Neuritis: Final Optic Neuritis Treatment Trial Follow-Up."
National Multiple Sclerosis Society: "Vision Problems."
Reviewed by Arefa Cassoobhoy, MD, MPH on February 09, 2018
This tool does not provide medical advice. See additional information.
THIS TOOL DOES NOT PROVIDE MEDICAL ADVICE. It is intended for general informational purposes only and does not address individual circumstances. It is not a substitute for professional medical advice, diagnosis or treatment and should not be relied on to make decisions about your health. Never ignore professional medical advice in seeking treatment because of something you have read on the WebMD Site. If you think you may have a medical emergency, immediately call your doctor or dial 911.
