What It Really Means When Your Vision Is Blurry

Blurry vision may come on suddenly or it may develop slowly over a period of time. In most instances, this common eyesight problem is nothing to worry about, but it definitely can be annoying. When you can't see clearly, it's difficult to do daily tasks, such as working on a computer or reading. And of course, it can be dangerous to attempt some things, like driving, when your vision is compromised.

Finding out the cause of the blurriness will not only help you get your vision back to normal more quickly, but it will help identify a cause that needs immediate treatment before your eyesight worsens or you develop further complications. The message is never to ignore or downplay blurry vision.

"Sight is such a valued sense, but there are still a lot of problems that fall through the cracks," Rajiv Shah, M.D., assistant professor of ophthalmology at Wake Forest Baptist Medical Center, told Health. Whether blurry vision comes on suddenly or has slowly snuck up on you, you should know what the possible causes are.

One of the most common reasons for blurry vision is the need for glasses or a new prescription (per Health). If you're having trouble seeing things clearly that are 20 feet away, you're probably nearsighted (aka myopic). If you see things in the distance with clarity, but closer objects appear fuzzy, you're likely farsighted (aka hyperopic). Both problems can be fixed with the proper prescription for glasses or contact lenses. Most people after the age of 40 develop presbyopia, when reading becomes difficult. If you have to hold a book farther away from your face to see the words clearly, you probably need reading glasses.

Other causes of blurry vision are related to aging. Cataracts, which affect about half of all Americans over 75, develop when the lens at the front of the eye becomes cloudy and blocks light from reaching the retina. This condition can take a long period of time to be noticed, until vision at any distance becomes cloudy or foggy. Open-angle glaucoma, which is the result of damage to the optic nerve (per Mayo Clinic) from high pressure in the eye, is the leading cause of blindness in those over 60. The degradation of vision is so gradual it may not be addressed until the glaucoma is advanced.

Another cause of fuzziness that may not be noticeable at first is sleeping with your contacts in. When contacts move, they create tiny scratches on the eye, which can become infected, blurring vision. Be sure to give your eyes a break nightly.

Sudden blurriness can be due to something serious — or not. Here are a few possibilities. 

If you wake up one morning and you can't see clearly in one eye, it may be due to a vein occlusion, which is a mini-stroke in the eye (per Health). The likely cause is high blood pressure. To be effective, treatment has to begin quickly, so this is one case when you should contact your doctor ASAP.

Other reasons for calling the doctor right away include a detached retina. Symptoms consist of seeing floating black specks, shadows on the sides or in the middle of your field of vision, or flashes of light in one or both eyes, according to Medical News Today. A stroke can also cause sudden blurry vision. Other symptoms include numbness, weakness, confusion, dizziness, and severe headache. In case of stroke, call 911 or head to the ER. There are a variety of conditions that lead to eye inflammation and must be addressed as soon as possible. When blurry vision is accompanied by severe eye pain, immediate treatment is needed.

Blurry vision can also come on suddenly in other not-so-dire circumstances, such as when you've been focusing on a computer screen for an extended period with no break or when you're under a lot of stress. In this case, however, blurry vision should be mild and temporary, according to All About Eyes. Finally, tears that dry on your eyes at night, not on your pillow, can cause morning blurriness (per Healthline). Blinking a few times will help.