Blurry Vision in One Eye

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Blurry Vision in One Eye: Causes and What to Do

There are many reasons you might experience blurred vision in just one eye. Oftentimes, blurry vision indicates the need for eyeglasses or a stronger lens prescription. However, it can also signal an underlying condition that requires prompt medical attention.

Most causes of blurred vision aren’t life-threatening. But when blurry vision appears suddenly or only affects one eye, it can be a warning sign of a medical emergency. Notify your doctor anytime you experience sudden or persistent blurry vision.

When is Blurry Vision a Medical Emergency?

Sometimes, blurred vision in one eye can signify a serious condition that needs emergency treatment. It’s important to be aware of the signs of these conditions so you know when to seek medical care.

Call 911 or your local emergency number if you or anyone else experiences blurry vision with any of the following symptoms:

  • Severe headache that comes on quickly
  • A headache that follows a blow to the head 
  • Loss of consciousness
  • Difficulty staying awake
  • Numbness, drooping, or weakness on one side of the face or body
  • Slurred speech
  • Difficulty raising one or both arms

People with diabetes should seek immediate medical care if they experience:

  • Sudden changes in vision, such as flashes of light
  • An unusual increase in eye floaters
  • Sudden vision loss, especially after coughing or sneezing
  • Seeing shadows, curtains, or cobwebs in your field of vision

What Causes Blurry Vision In One Eye?

Blurred vision can result from many conditions. Most causes aren’t serious, but some can lead to permanent vision loss or even death.

Serious Causes of Blurred Vision in One Eye

Stroke

Blurry vision can occur when a stroke affects the brain regions associated with vision. A stroke happens when something reduces or blocks the blood flow to part of your brain.

Remembering the acronym FAST can help you identify the symptoms of a stroke. FAST stands for:

  • Face drooping
  • Arm weakness
  • Speech difficulty
  • Time to call 911

Sudden changes in vision, difficulty walking and speaking, and severe headaches can also be stroke symptoms.

Transient Ischemic Attack

A transient ischemic attack (TIA) involves temporary stroke symptoms. A TIA is sometimes called a mini-stroke, but that doesn’t mean it isn’t serious. A TIA can be a warning sign of an impending stroke.

Brain Tumor

Blurred or double vision can be due to a brain tumor in the occipital lobe, temporal lobe, or brain stem. Other symptoms of a brain tumor include:

  • Memory loss
  • Difficulty speaking
  • Persistent headaches
  • Trouble concentrating
  • Balance and coordination problems
  • Weakness on one side of the body

Retinal Detachment

A detached retina can lead to blurry vision in one eye. The retina is the light-sensitive tissue at the back of your eye.

Increased light flashes and floaters can be early symptoms of retinal detachment. However, this condition can happen suddenly and without other symptoms.

Wet Macular Degeneration

There are two types of age-related macular degeneration (AMD): wet and dry. Both conditions can cause blurred vision that starts in one eye and progresses to the other. Both types cause blurriness and vision loss in the middle of your visual field (central vision).

Unlike the dry type, wet AMD starts suddenly and worsens rapidly. Although dry AMD progresses gradually, it can turn into the wet type and cause sudden symptoms.

Closed-Angle Glaucoma

Closed-angle glaucoma occurs when the fluid in your eyes can’t drain properly. This causes a buildup of intraocular pressure. The increased pressure can damage the optic nerve and cause vision loss.

Closed-angle glaucoma usually affects one eye. Other symptoms include:

  • Headache
  • Intense eye pain
  • Nausea and vomiting
  • The appearance of halos around lights

Endophthalmitis

Endophthalmitis is an ocular fluid infection that can cause severe inflammation. It’s a serious medical emergency that can occur after surgery. Symptoms include:

  • Blurry vision
  • Swollen eyelids
  • Pus draining from the eyes

Diabetic Retinopathy

People with diabetes should be aware of a serious condition called diabetic retinopathy. High blood sugar levels can damage the blood vessels in the retina, causing blurred vision. Other symptoms of diabetic retinopathy include:

  • Double vision
  • An increase in floaters and dark spots
  • Poor night vision

Eye or Head Injury

Blurry vision that follows an injury to the eye or head can indicate a medical emergency. Call your doctor right away if vision changes occur after an injury.

Non-Emergency Causes of Blurry Vision in One Eye

Most eye conditions that cause blurry vision aren’t life-threatening. However, you should still see your doctor for an evaluation and diagnosis.

Refractive Errors

Refractive errors are among the most common eye problems that cause blurred vision. Different types of refractive errors include:

Aside from blurry vision, common symptoms of refractive errors include:

  • Eye strain
  • Headaches
  • Hazy vision
  • Double vision
  • Seeing halos around lights

Refractive errors are treatable with glasses, contact lenses, or refractive surgery.

Migraines

Migraines are severe, pounding headaches that usually involve other symptoms. Some people experience a period of visual disturbances before a migraine attack. 

This is known as the aura, and it can cause the following visual symptoms:

  • Blurry vision
  • Temporary vision loss
  • Seeing squiggly lines or shapes

Cataracts

Cataracts cause cloudy vision in one or both eyes. This condition is common in older adults. Symptoms of cataracts include:

  • Blurry or hazy vision
  • Colors that look less vivid
  • Difficulty reading
  • Trouble seeing at night
  • Double vision
  • Seeing halos around lights

Cataract surgery is the only way to treat cataracts.

Eye Infections

Eye infections that can lead to blurry vision include:

  • Conjunctivitis. Also called pink eye, this is an infection of the clear membrane outside your eye.
  • Keratitis. This is corneal inflammation that’s usually due to an infection. Wearing the same pair of contacts for too long, reusing dirty contacts, and sleeping in contacts can cause keratitis.
  • Uveitis. Uveitis is inflammation of the colored parts of the eye, including the iris. It can be caused by an infection or an autoimmune response.

Optic Neuritis From Multiple Sclerosis

Multiple sclerosis (MS) can cause inflammation around the optic nerve (optic neuritis). Symptoms of optic neuritis include:

  • Blurred vision
  • Loss of color vision
  • Eye pain when moving the eyes

These symptoms usually affect only one eye.

Other Causes

Other causes of blurry vision in one eye include:

  • Corneal abrasion
  • Certain medications
  • Dry eye
  • Eye strain
  • Preeclampsia (high blood pressure during pregnancy)
  • Psoriasis

Risks & Complications of Blurry Vision In One Eye

In rare circumstances, blurry vision can be due to a serious disease or condition. If left untreated, this can lead to vision-threatening or life-threatening complications, including

  • Vision loss
  • Brain damage
  • Spread of cancer
  • Spread of infection
  • Unconsciousness

Blurry Vision Treatment

Blurry vision treatment depends on the cause. Eyeglasses or contact lenses can treat refractive errors, and eye drops can treat dry eyes.

Medical conditions, such as stroke, must be treated by a doctor. Some conditions may require eye surgery, like LASIK, to fix blurry vision.

If you have blurry vision in one eye, contact your eye doctor to assess your condition's underlying cause. You may have to take an eye exam to determine the cause of your vision problems. If necessary, your doctor will prescribe you treatment to help.

Summary

  • Blurry vision usually isn’t caused by a life-threatening condition
  • Sudden blurry vision in one eye may be due to a serious eye condition or other health problem that requires emergency medical care
  • Serious health conditions that can cause blurry vision include stroke and diabetic retinopathy
  • Refractive errors are the most common causes of blurry vision
11 Cited Research Articles
  1. Vision problems.” MedlinePlus, 2020.
  2. Corneal abrasion.” Harvard Health Publishing, 2019.
  3. Conjunctivitis (pink eye).” Centers for Disease Control and Prevention, 2019.
  4. Cataracts.” National Eye Institute, 2019.
  5. Fredrick, D R. “Myopia.” BMJ, 2002.
  6. Presbyopia.” National Eye Institute, n.d.
  7. Age-related macular degeneration.” National Eye Institute, 2021.
  8. Preeclampsia.” MedlinePlus, 2020.
  9. Srinivasan, M et al., “Distinguishing infective versus non infective keratitis.” Indian journal of ophthalmology, 2008.
  10. Eye strain.” Health Direct, 2021.
  11. 7 Warning Signs Of A Brain Tumor You Should Know.” Weill Cornell Medicine, 2016.
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The information provided on VisionCenter.org should not be used in place of actual information provided by a doctor or a specialist.

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