Blurry Vision in One Eye

Whether it's gradual or sudden, experiencing blurry vision in one eye can be alarming. And with causes ranging from mild to severe, it's a good idea to have an understanding of what might be behind things looking fuzzy out of one of your eyes.

Causes

Though they may sound similar, there is a difference between "blurry" and "cloudy" vision.

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

Here, we're going to focus on blurry vision: specifically, when it occurs in only one eye.

Along the same lines, there are many conditions that can result in blurry vision in either one or both eyes, and here we'll feature conditions that, in most cases, affect only one eye.

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 a little later on. 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 through 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.

Other than the abnormal pupil size and blurry vision in one eye, other symptoms of Adie's pupil include:

• 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: Either to make a pupil smaller and reduce light sensitivity, as well as to reduce glare while driving at night.

Optic Neuritis

Optic neuritis is the inflammation of the optic nerve, and typically only affects one eye. Though the exact cause is still unknown, it may be caused by an infection. Optic neuritis also affects roughly half of people with multiple sclerosis (MS), a progressive, neurologic disorder, and it is 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 following a hot shower or a workout
• 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 the blurry vision becomes vision loss, it typically peaks within a few days and starts improving within four to 12 weeks.

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

Eye Stroke

Also known as a retinal artery occlusion (RAO), an eye stroke is a blockage in one or more of the arteries of the retina, caused by a clot or a build-up of cholesterol in an artery. There are two types of RAOs:

• 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 considered a form of a stroke in the eye, requiring emergency medical attention.

In addition to sudden, painless, blurry 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

Though there isn't one consistent treatment with high levels of success, some methods that can be helpful 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

More men than women develop this eye disease. 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.

The condition is painless and doesn't usually come with other symptoms.

At this point, there are no effective treatments for leber hereditary optic neuropathy, but antioxidant supplements are sometimes used, and scientists are working on genetic therapy treatments.

When to See a Doctor

Really, anytime you experience blurry vision in one eye (or both eyes), it's time to see an eye doctor. Because it's possible for one eye to 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 out of nowhere—or is accompanied by other symptoms—then you should seek immediate medical attention. Not only is it a safety hazard, given that your vision is limited, it could also be a sign of a more serious condition.