Lifestyle

Sudden Blurry or Lost Vision in One Eye Can Be an Eye Stroke. Signs That Need Care Right Away

By Mike Harper · November 1, 2026

Vision that blurs or goes dark in one eye in a matter of moments, often with no pain at all, is not something to wait out.

That sudden change can be a retinal artery occlusion, often called an eye stroke. The American Academy of Ophthalmology describes it as blood flow to the eye’s retina being blocked. The retina needs a constant supply of blood to see, so a blockage can cause temporary or permanent loss of vision. The academy says cholesterol, platelets or calcium building up inside the arteries that carry blood from the heart to the eye can cause the blockage.

Cleveland Clinic estimates eye strokes affect about 1 to 2 per 100,000 people each year, and the academy says they are most commonly found in people in their sixties, especially men.

These are the warning signs described by the academy, Cleveland Clinic and MedlinePlus.

Sudden, painless vision loss. The academy calls this the most common symptom. Vision may go in all of one eye or in part of it.

Blurred vision. MedlinePlus describes sudden blurring or loss of vision in all or part of one eye.

Blind spots or darkness. Cleveland Clinic and the academy both list blind spots, and Cleveland Clinic adds darkness in the vision.

Loss of side vision. The academy lists a sudden loss of peripheral, or side, vision.

Distorted vision. The academy says things may suddenly look wavy or out of shape.

Floaters and flashes. Cleveland Clinic includes them among the changes in one eye, along with vision changes that start out small but get worse over time.

Vision that comes back. MedlinePlus says an occlusion may last only a few seconds or minutes, or it may be permanent. Cleveland Clinic says to seek medical help even if your vision loss is temporary, because it can be caused by a “mini-stroke” in the eye.

Time matters for two reasons. The academy says certain studies have shown that an untreated occlusion lasting just over an hour and a half can lead to permanent vision loss. It also says people who have one are at risk for a brain stroke, and that the risk is very high right after and up to four weeks afterward. MedlinePlus adds that a clot in the eye may be a warning sign of clots elsewhere.

For those reasons, the academy’s advice is direct: anyone with these symptoms should go to a hospital emergency department or an ophthalmologist right away. It says quick diagnosis and treatment can help prevent a brain stroke and may help save vision.

Along with a dilated eye exam, doctors may look for the source of the blockage. The academy and MedlinePlus list an ultrasound of the carotid arteries in the neck and an echocardiogram, an ultrasound of the heart.

Treatment options are limited. MedlinePlus says several treatments may be tried but must be given within 2 to 4 hours after symptoms begin, and their benefit has never been proven. The academy says some people regain part of their sight, although they may not see as well as before.

The risk factors mirror those for a brain stroke. The academy lists smoking, obesity, heart or lung disease, diabetes, high cholesterol, high blood pressure, a narrowed carotid artery, blood clotting problems and older age. MedlinePlus adds heart rhythm problems, mainly atrial fibrillation, and heart valve problems. Cleveland Clinic says managing blood pressure and cholesterol, keeping blood sugar steady, quitting smoking and seeing an eye care provider regularly may lower the risk.

This article is for general information and is not medical advice. Sudden vision loss in one eye is an emergency, so go to an emergency department or call 911 right away, even if your sight returns. This article was produced with the assistance of AI and fact-checked against the sources cited by LightWave Reports.