Is Blurred Vision in One Eye Serious?

It can be alarming to experience blurry vision, whether it's gradual or sudden. With causes ranging from mild to severe, it's can help to understand what might be behind things looking fuzzy out of one of your eyes.

The most common cause of blurred vision is a refractive error. This can cause near-sightedness or far-sightedness. This cause isn't an emergency, but blurred vision in one eye could be due to glaucoma, a detached retina, an "eye stroke," and other causes. Particularly if symptoms come on suddenly, you should seek medical attention right away.

Many conditions can result in blurry vision in either one or both eyes. This article will feature conditions that affect only one eye.

What Causes Blurry Vision in One Eye?

They may sound similar, but there's a difference between blurry and cloudy vision:

• Blurry vision means what you're seeing is out of focus.
• Cloudy vision feels like you're looking at everything through a fog or a haze.
  

Amblyopia

Also known as "lazy eye," amblyopia causes blurry vision in only the affected eye.

Other symptoms include:

• Lacking depth perception
• Squinting
• Shutting one eye
• Tilting the head to one side

Some children are born with amblyopia, while others develop the condition later. It's the most common cause of vision loss in kids.

Treatment for amblyopia involves re-training the brain and forcing it to use the weaker eye. This is typically done by wearing an eye patch or putting blurring eye drops in the dominant eye.

Adie's Pupil

Adie's pupil is a neurological disorder where one pupil doesn't react normally to light. The affected pupil is typically larger than normal and doesn't get smaller in the presence of bright light.

When the following symptoms accompany the abnormal pupil size and blurred vision in one eye, it is known as Adie's syndrome:

• A general sensitivity to light
• Difficulty reading
• Excessive sweating
• Not having a knee-jerk reflex

While there's no cure for the condition, it can be treated using:

• Eyeglasses: To improve reading or near vision
• Sunglasses: To reduce light sensitivity
• Eye drops: To make a pupil smaller, reduce light sensitivity, and reduce glare while driving at night

Optic Neuritis

Optic neuritis is optic nerve inflammation and typically only affects one eye. The exact cause of this is unknown.

Optic neuritis also affects about half of people with multiple sclerosis (MS), a progressive neurologic disorder. It's frequently the first symptom of the condition.

In addition to blurry vision in one eye, other symptoms of optic neuritis may include:

• Trouble distinguishing colors or
• Noticing that colors aren't as vibrant as usual
• Blurriness that worsens after your body temperature has risen, like after a workout or hot shower
• Inability to see out of one eye
• Abnormal reaction of the pupil when exposed to bright light
• Pain in the eye, especially when you move it

The symptoms can vary significantly, depending on the extent of the inflammation of the optic nerve. If blurry vision becomes vision loss, it typically peaks within a few days and starts improving within 4 weeks to 12 weeks.

In some cases, a doctor may prescribe steroids (usually injected into a vein) to treat optic neuritis. However, the condition will often go away on its own without treatment.

Eye Stroke

A retinal artery occlusion (RAO) is also called an eye stroke. It's a blockage in one or more arteries of the retina. An eye stroke is caused by a clot or cholesterol build-up in an artery.

The two types of RAOs are:

• Branch retinal artery occlusion (BRAO): This blocks the small arteries in the retina.
• Central retinal artery occlusion (CRAO): This is a blockage in the central artery in the retina and is considered a form of a stroke in the eye that requires emergency medical attention.

In addition to sudden, painless, blurred vision in one eye, an eye stroke can also result in sudden vision loss. This can occur in all or part of one eye.

Other symptoms can include:

• A loss of peripheral vision
• Distorted vision
• Blind spots

There is no effective treatment for this condition. The most important thing is to make sure you don't develop a cerebral artery infarction or a stroke.

If discovered early enough, helpful methods include:

• Breathing in a carbon dioxide-oxygen mixture that causes the arteries of the retina to dilate
• Removing some liquid from the eye to allow the clot to move away from the retina
• A clot-busting drug

Leber Hereditary Optic Neuropathy

Leber hereditary optic neuropathy typically begins when young adults experience blurriness or the loss of central vision in one eye, followed months or years later by vision loss in the other eye.

More men than women develop this eye disease. The condition is painless and doesn't usually come with other symptoms.

There are currently no effective treatments for Leber hereditary optic neuropathy, but antioxidant supplements are sometimes used. Scientists are working on genetic therapy treatments.

When to See a Doctor

Anytime you experience blurred vision in one eye (or both eyes), it's time to see an eye doctor.

One eye can develop nearsightedness or farsightedness while the other retains its full vision. Sometimes, blurry vision in one eye can be diagnosed with an eye exam and corrected using glasses, contact lenses, or refractive surgery.

A Word From Verywell

As a general rule, don't mess around when it comes to your eyesight. This includes experiencing blurry vision in one eye.

If the blurry vision becomes noticeable gradually, it's likely a normal change in vision that would require some type of corrective or treatment.

But when the blurry vision in one eye comes on suddenly, out of nowhere—or is accompanied by other symptoms—then you should seek immediate medical attention. It's a safety hazard since your vision is limited, but it could also be a sign of a more serious condition.