11 Causes of Blurry Vision in One Eye

Dr. Russel Lazarus, March 8, 2022

Are you experiencing blurry vision in just one eye? This could be a sign of a serious eye condition.

While blurry vision is often associated with a need for eyeglasses or a new optical prescription, monocular blurry vision can signal a more serious condition that requires immediate attention.

Blurry vision that comes on suddenly or appears only in one eye can be a sign of a medical emergency and should be evaluated immediately by an eye doctor or another medical professional.

Here are six emergencies that can cause blurry vision in one eye:

1. Stroke

Blurry vision in one or both eyes can occur when a stroke affects the visual areas of the brain. Seek immediate medical attention if you are experiencing any of the following symptoms along with blurry vision:

  • Severe headache
  • Disorientation
  • Difficulty speaking or understanding speech
  • Imbalance or walking issues
  • Numbness or tingling in extremities, especially on one side

2. Retinal detachment

Retinal detachment is an eye emergency that occurs when the retina is pulled away from its normal position on the back wall of the eye.

This sight-threatening condition generally results in a sudden onset of blurred vision, along with:

  • Flashes of light or eye floaters that move across your vision
  • Decreased peripheral vision
  • Appearance of a shadow or curtain in your visual field

3. Brain tumor

Brain tumors can put pressure on the visual processing areas of the brain and cause blurry vision, as well as other visual changes.

Other signs of a brain tumor include:

  • Persistent headaches
  • Confusion or difficulty concentrating
  • Memory loss
  • Trouble speaking
  • Weakness of one side of the body
  • Balance and coordination issues

4. Closed-angle glaucoma

Closed-angle glaucoma is an eye emergency that occurs when ocular fluid cannot drain properly, resulting in a sudden buildup of intraocular pressure. The elevated pressure presses on the optic nerve, causing permanent damage and vision loss, usually in one eye.

Other signs of closed-angle glaucoma include:

  • Headache
  • Severe eye pain
  • Nausea and vomiting
  • Seeing halos around lights

5. Wet macular degeneration

Macular degeneration (AMD) is a sight-threatening eye condition that affects the macula, the center of the retina, responsible for central vision and vision for fine details.

There are two forms of macular degeneration: dry and wet.

In the wet form, one eye may suddenly experience a bleed or leakage of fluid, resulting in an immediate loss of vision in that eye – this is an eye emergency.

One of the first signs of AMD is blurry vision in one or both eyes.

Other signs of AMD include:

  • Appearance of dark or blind spots in your central vision
  • Wavy vision or other visual distortions in your central vision
  • Difficulty reading and driving
  • Trouble with facial recognition
  • Inability to see fine details

6. Diabetic retinopathy

Diabetic retinopathy is a serious eye condition that affects people with diabetes. It develops when elevated blood sugar levels remain high for long periods of time, damaging the tiny blood vessels throughout the body, including in the retina.

When the retinal blood vessels become damaged, they begin to leak fluid, resulting in retinal swelling and blurred vision.

Other signs of diabetic retinopathy include:

  • Double vision
  • Seeing floaters in your field of vision
  • Increasing dark spots in your field of vision
  • Poor night vision

SEE RELATED: Why Is There Excess Fluid in My Eye?

Contact an eye doctor near you if you are experiencing blurry vision or any other visual changes. 

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5 less-urgent causes of blurry vision in one eye:

While the following causes don’t usually require an emergency trip to the eye doctor, treatment is still necessary to prevent any complications.

1. Conjunctivitis (pink eye)

Conjunctivitis, commonly known as pink eye, is an inflammation of the conjunctiva, the thin membrane that covers the white part of the eye and lines the inner eyelids. It can occur in one or both eyes, and while mild cases don’t usually impact vision, more serious cases can result in blurry vision.

Other symptoms of pink eye include:

  • Whites of the eye appear red or pink
  • Itching or burning in the eye
  • Swollen eyelids
  • Gritty sensation in the eye
  • Excessive tearing
  • Discharge from the eye

2. Other eye infections

Many different eye infections can result when bacteria, viruses or fungi enter the eye. Any of these infections can lead to blurry vision.

Common eye infections that result in blurry vision include:

3. Retinal migraine     

A retinal migraine causes blurry vision and temporary blindness in one eye that usually lasts less than one hour. It can precede a headache or appear during, or after a headache.

4. Cataract

A cataract is the clouding of the eye’s naturally transparent lens, resulting in blurry vision in that eye. Although cataracts generally develop in both eyes, the clouding of the lens can occur at different rates, causing a difference in severity of blurred vision between the two eyes.

Other signs of a cataract include:

  • Sensitivity to glare from sunlight, bulbs, headlights
  • Seeing halos around lights
  • Poor night vision
  • Colors appearing less vibrant
  • Double vision

5. Eye strain

Eye strain is often a symptom of excessive screen time or a prolonged near vision activity. Eye strain often leads to other uncomfortable symptoms, including:

  • Blurry vision
  • Headache
  • Eye fatigue
  • Dry eyes
  • Neck and shoulder pain

LEARN MORE: Guide to Eye Health  

If you are experiencing blurry vision, schedule an eye exam to determine the cause and learn about treatment options. 

Blurry vision in one eye is a common symptom with a number of possible causes.

Seek immediate medical attention if you experience a sudden onset of blurry vision or any other symptoms that signal a medical emergency.