Blurred vision is loss of vision sharpness in one or both eyes. It may affect your entire field of vision, your periphery (side) vision, or only parts of your vision.

When you have blurry eyes, the world no longer appears in focus, and you may have difficulties working, reading, or performing everyday tasks.

In this post, we’ll review some of the most common causes of blurry vision. While some are harmless, others can be a sign of a serious disease.

So it’s important to pay attention to when you have blurry eyes and what other symptoms may accompany them.

1. Refractive Errors

Refractive errors cause images not to be focused exactly on the retina, resulting in blurry eyesight.

  • If you are nearsighted (myopia), objects in the distance will appear blurred.
  • If you are farsighted (hyperopia), close-up objects will be blurry, though distant ones may also appear blurred.
  • Having an irregularly shaped cornea (astigmatism) causes blurry vision at all distances.
  • Presbyopia, or age-related vision decline that usually occurs after 40, may also blur your vision.

When it’s caused by refractive errors, blurry vision doesn’t go away. You can correct refractive errors with eyeglasses, contact lenses, or surgery.

blurry image of man holding a pair of eyeglasses

2. Eye Drops and Certain Medication

Eye drops are often used to treat eye conditions. But they may cause blurred vision, irritation, and other symptoms. The main culprits are eye drops that contain preservatives.

Other medication may also cause temporary vision changes, including allergy pills, sleeping aids, high blood pressure medication, and antihistamines.

3. Eye Allergies

Common triggers for eye allergies are pollen, pet dander, dust mites, perfume, makeup, detergent, and other chemicals. Eye allergies can cause a variety of symptoms, including blurry eyes.

4. Eye Strain

Mild blurry vision that lasts only a short while can be due to eye strain. Some of the common causes of eye strain are working for hours at a computer, studying intensely, or using devices with screens for long periods.

Tip: We've written a post on how to reduce computer eye strain.

5. Overexposure to Sunlight

Bright, intense sunlight and the glare that comes with it can cause temporary blurry vision. UV light from the sun can damage your eyes. So it’s a good idea to grab a pair of sunglasses with good UV protection each time you head out into the sun.

sun glare behind a man with eyeglasses facing the viewer

6. Eye Floaters

Eye floaters occur when microscopic fibers within the jelly-like substance that fills the eyeballs clump together and cast shadows on the retina. This process typically occurs with age.

Eye floaters may cause temporary blurriness in the eye. A sudden increase in eye floaters can indicate a serious problem with the retina. If you experience that, it’s important to see a doctor.

7. Sleeping Face Down

If you’re wondering, “Why is my vision blurry in the morning?” the surprising answer may be the position in which you sleep.

Sleeping on your face may reduce the elasticity of the upper eyelid, a condition known as floppy eyelid syndrome. This condition may cause blurred vision after waking.

8. Pregnancy

During pregnancy, hormonal changes alter the cornea and may cause blurred vision. Tell your doctor about any vision changes you experience during pregnancy.

In addition to hormonal changes, other underlying causes of blurry vision while you’re pregnant may include dry eyes, high blood pressure, or gestational diabetes.

9. Migraines

Some migraines begin with vision disturbances that may include temporary blurry vision. Migraines with aura are a common example.

Understanding your migraine triggers may help you avoid them. If your migraines are severe or reoccurring, you want to discuss them with a doctor.

woman lying on mattress with arm to her head having a migraine

10. Eye Diseases

A variety of eye diseases may cause blurred vision, some of them more serious than others.

  • Cataracts is the clouding of the lens of the eye, typically occurring in people over 60.
  • Age-related macular degeneration affects the macula at the center of the retina responsible for detailed vision. It also occurs predominantly in the elderly and may cause blurry sight alongside visual distortions.
  • Diabetic retinopathy is a diabetes complication that damages the blood vessels in the retina. Fluid leaks from these, causing the retina to swell and leading to blurry vision and other symptoms.
  • Glaucoma damages the optic nerve connecting the eye to the brain, and is often the result of high pressure in the eye. Blurred vision may be a symptom of glaucoma.

When blurry vision keeps reoccurring or doesn’t go away, it can be a sign of these and other serious eye diseases. Seeing a doctor is very important to get prompt treatment that can help you preserve your vision.

11. Eye Surgery

You may also experience blurry vision after refractive eye surgery such as LASIK. In some cases, the blurred vision lasts longer than a few days. But your vision gradually stabilizes as your eyes adjust to the changes in the cornea.

Good to know: Dry eyes after eye surgery are also common.

12. Wearing Contact Lenses for Too Long

If you find yourself thinking, "My vision is blurry while wearing contact lenses...I wonder why?" it could be because of your contact lenses.

Debris from the tear film that lubricates the eye may build on the lenses. Usually, this happens if you wear the contacts beyond the prescribed date.

13. Diabetes and Blood Sugar Imbalances

Blurred vision may also be a sign of fluctuating blood sugar levels. High blood sugar levels make the lens of the eye retain water and swell, blurring your vision. This typically occurs in people with diabetes.

hand putting sweetener into coffee cup while the other hand holds the saucer

Blurred vision may also be a sign of undiagnosed diabetes, so you don’t want to neglect it if it reoccurs.

14. Stroke and Other Serious Diseases

Sudden blurry vision can be a sign of a stroke or another medical emergency. Other serious health conditions may cause blurry vision, including cardiovascular disease, diabetes, multiple sclerosis, and certain types of cancer.

15. Chronic Dry Eyes

Dry eye disease is one of the leading causes of blurred vision in the digital age. The blurriness may come and go and affect different parts of your eyes.

The underlying cause is insufficient tear production or imbalances in the tear film that lubricates your eyes.

Chronic dry eyes may make it harder for you to read, drive, or use a computer or smartphone. Left untreated, it may cause eye infections and damage the surface of your cornea.

Do you think you may have dry eyes? Our quick online test can help you find out.

Take the Dry Eye Test.

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