Sudden blurry vision may be your body’s way of alerting you about a serious health problem.
“Many conditions can cause blurry vision, and not all of them are medical emergencies,” says Dr. Saeed Rehman, a board-certified emergency medicine physician at Beaufort Memorial Pratt Emergency Center. “Cataracts, for example, can cause blurry vision to develop over time. However, when blurry vision appears suddenly, that’s concerning because it could indicate a stroke or another issue that needs medical attention right away.”
Below are some causes of sudden blurry vision that warrant a trip to the nearest emergency room (ER).
Read More: Safe Care at the ER
Stroke
A stroke occurs when the brain doesn’t receive enough oxygen because of a blocked or burst blood vessel. It may cause sudden blurry vision in one or both eyes if it affects an area of the brain that controls sight.
“If you suddenly experience blurry vision, look for other symptoms that could indicate a stroke,” Dr. Rehman says. “These include sudden weakness or numbness on one side of the body, an intense headache, and difficulty speaking or walking. If you develop any of these symptoms, call 911 right away so emergency medical services can take you to the nearest ER.”
An abbreviated form of stroke called a transient ischemic attack (TIA) can also cause blurry vision. Like a stroke, a TIA is a medical emergency. Some people who experience a TIA later go on to have a stroke.
Read More: For Stroke Victims, Timing is Everything
Migraine
A migraine is an intense headache that can last hours or days. Beyond pounding pain in the head, migraines can cause additional symptoms, including blurry vision and other vision changes.
Many migraine-associated vision symptoms occur as auras. These are warning signs that precede classic migraines. Vision changes may also take place during retinal migraines, which are rare and affect only one eye.
If you have a history of migraines, associated vision symptoms may be normal for you. If, however, you experience blurry vision or vision changes for the first time, it’s important to go to the ER so emergency medicine providers can evaluate you and rule out other causes, such as a stroke.
Read More: What Is the Best Way to Get Rid of a Headache?
Eye Injury
You can also develop blurry vision if you’re hit in the eye on the job or while playing sports, or a chemical irritant gets in your eye. Any accident that might impact your vision requires emergency care to prevent possible permanent vision loss. For instance, serious eye injuries can lead to a detached retina. This is when part or all of the retina — the eye’s light sensor that communicates with the brain — breaks free from the back of the eye.
Concussion
A blow to the head may cause a concussion, a type of traumatic brain injury that can damage brain cells and cause a variety of symptoms. One concussion symptom is blurry vision, and it could be a sign that the concussion is serious enough to need emergency medical attention.
“Blurry vision is common following a concussion,” Dr. Rehman says. “It’s concerning if blurry vision doesn’t go away on its own and is accompanied by a persistent or worsening headache, slurred speech, vomiting, or seizures. If you have any of these symptoms, call 911 or go to the nearest ER.”
A severe concussion may cause brain swelling, which can lead to a stroke. This type of concussion can also cause a blood clot in the brain known as a hematoma. Changes to vision may be a sign of a serious, concussion-related brain injury. Look for other signs that may be evidence of this type of injury, including a headache that is constant or comes and goes, poor balance, confusion, and difficulty focusing on a task.
If you experience sudden blurry vision or another concerning symptom, call 911.
