If you’re experiencing blurry vision, it could be a sign of uncorrected or under corrected refractive error such as myopia (nearsightedness) or hyperopia (farsightedness). This could also be a sign astigmatism has worsened and you need new eyeglasses or contact lenses. In some instances, persistent blurry vision can signal the presence of an eye disease. The following summary can help you differentiate potential causes of blurry or hazy vision.
Refractive errors: As already mentioned, nearsightedness, farsightedness, or astigmatism can cause blurry or out-of-focus vision. In addition to not seeing clearly, uncorrected refractive errors can cause eye strain, headaches, double vision, glare or halos around bright lights, and squinting. Refractive errors can be easily corrected with glasses or other interventions, yet half of all cases worldwide remain undetected or untreated. Uncorrected refractive error is responsible for 43% of global vision impairment.
Presbyopia: If you are age 40 or older and experiencing blurry vision, you may have this common eye problem. The clear lens inside the eye behind the colored iris changes shape to focus light onto the retina so people can see clearly. In younger people, the lens is soft and flexible, therefore it easily changes shape. This enables a person to focus on both near and far away objects. After age 40, the lens becomes more rigid so the ease of the lens changing shape diminishes. This makes it harder to read, thread a needle, or do other close-up tasks.
Chronic dry eye: When a person suffers from dry eye syndrome, this can cause blurry vision unrelated to refractive errors. Artificial tears (lubricating eye drops) can help alleviate dryness and blurry vision. In more advanced cases, prescription medications or punctal plugs may be warranted to keep eyes healthy and lubricated.
Temporary Causes of Blurry Vision
Ocular migraines/migraine attacks: Regular migraine attacks can cause vision problems, called an aura. This can involve flashing lights and blind spots, which typically impact both eyes. Unlike other underlying causes, blurry vision associated with migraines is fleeting. It usually results in vision loss or blindness in one eye for less than an hour.
Eye floaters: These little “cobwebs” or specks float about in one’s field of vision and can induce the sensation of blurred vision temporarily. They are small, dark, shadowy shapes resembling spots, thread-like strands, or squiggly lines. They move as your eyes move and seem to dart away when you try to look at them directly. Floaters are caused by deposits or condensation in the vitreous (also called vitreous humor, vitreous fluid, or vitreous gel), the material that fills the back part of the eye. In some instances, floaters can be a sign of a retinal detachment, which is considered a medical emergency.
LASIK surgery: Immediately following LASIK surgery, vision may be blurry. This typically improves within a couple of days, however, it may take several weeks for vision to stabilize completely.
Blurry Vision Related to Eye Disease
Eye conditions and diseases: If you are age 60 or older and experience the sudden onset of blurry vision in one eye, this could be caused by a macular hole in the part of the retina where fine focusing occurs. Blurry vision can also be a sign of a detached retina, eye herpes, or optic neuritis (inflammation of the optic nerve).
Diabetic retinopathy: A complication of diabetes, this serious eye disease causes progressive damage to blood vessels in the retina. The tiny blood vessels leak blood and other fluids, causing the retinal tissue to swell, resulting in cloudy or blurred vision.
Cataracts: When a cataract grows large enough, it clouds an extensive surface area of the lens. The clouded area distorts light that passes through the lens, eventually causing clouded, blurred, or dim vision. Other symptoms include increasing difficulty with night vision, sensitivity to light, glare or halos around bright lights, frequent changes in eyeglass or contact lens prescriptions, fading or yellowing of colors, and double vision in a single eye.
Glaucoma: Although this serious eye disease often causes no symptoms early on, it can result in a gradual or sometimes sudden narrowing of one’s field of vision accompanied by blurred peripheral vision. Once vision has been lost, it cannot be restored, however, treatment can reduce or slow additional vision impairment.
Age-related macular degeneration: This age-related eye disease causes damage to the macula, a small spot near the center of the retina. The primary function of the macula is to provide sharp, central vision. As AMD progresses, most people experience a blurred area near the center of vision. The blurred area may grow larger or people may develop blank spots in their central vision. Objects also may not appear as bright as they used to be.
If you are experiencing chronic blurry vision, schedule an appointment with an eye doctor as soon as possible.