Blurry vision is not always a cause for concern, but it can be a sign of a detached retina, a stroke, an infection, and various other conditions that may need medical attention.

Keep reading for more information on what can cause sudden blurry vision, when to seek urgent medical advice, and the treatment options available.

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A detached retina is a possible cause of sudden blurry vision.

A detached retina occurs when the retina, which is the thin layer at the back of the eye, pulls away from the blood vessels that provide it with essential oxygen and nutrients.

According to the National Eye Institute, symptoms can appear quickly. Without rapid treatment, permanent damage and vision loss can occur.

Symptoms can include:

  • gray or black specks floating in their vision
  • a shadow on the sides or middle of the person’s vision
  • flashes of light that can occur in one or both eyes

Treatment

There may be permanent damage to vision without rapid treatment.

Treatment will include reattaching the retina. A doctor may recommend freeze treatment, laser surgery, or surgery.

A person can learn more about the treatment for a detached retina here.

A concussion occurs when a person experiences an injury to the head.

Along with visual changes, symptoms of a concussion can include:

Treatment

After a doctor has ensured that the injury is not severe, treatment focuses on reducing the symptoms.

A person may need to rest for roughly 24–48 hours.

A person can also take over-the-counter (OTC) analgesics to help reduce headache symptoms.

According to a 2020 article, a person should avoid taking medications that can alter a person’s cognitive function and sleep patterns, as these might hide symptoms of a concussion.

Strokes can cause vision to become blurry in one or both eyes.

Symptoms of a stroke include:

  • numbness in the face, leg, or arm, typically on one side of the body
  • confusion and difficulty speaking, or understanding
  • difficulty seeing in one or both eyes
  • difficulty walking, as well as dizziness and lack of coordination
  • sudden and severe headache

If a person thinks that someone is experiencing a stroke, they should call the emergency services immediately and follow the procedure set out by the acronym FAST:

  • F for face: Ask the person to smile and note if one side of the face has dropped.
  • A for arms: Ask the person to raise both of their arms and note if one arm drifts downwards.
  • S for speech: Ask a person to repeat a simple phrase. Make a note if they slur their speech.
  • T for time: If any of the above has occurred, call the emergency services immediately.

Treatment

According to the Centers for Disease Control and Prevention (CDC), treatments are more effective within 3 hours of the onset of the first symptoms.

Treatment for a stroke will depend on the type of stroke, which part of the brain it affects and what caused the stroke.

A person can learn more about the treatments for a stroke here.

Endophthalmitis is a severe infection and inflammation of the fluid or tissue inside the eye.

As well as sudden blurry vision, symptoms may include:

  • eye pain
  • redness
  • sensitivity to light.

According to the American Academy of Ophthalmology, blindness can occur if a person does not receive treatment quickly.

Treatment

Treatment can include antibiotic or antifungal injections. Emergency surgery may be necessary.

A hyphema occurs when blood pools in the eye. Injury, trauma, and infections can cause a hyphema.

Symptoms may include:

  • bleeding in the eye
  • light sensitivity
  • pain
  • blurry vision

Treatment

To treat a hyphema, a person may need to:

  • wear a shield over the eye
  • rest
  • raise the head of the bed to help the eye drain

A person may need also need eye drops.

If the hyphema causes high pressure in the eye, an ophthalmologist may offer to remove the blood surgically.

GCA, or temporal arteritis, is an inflammation of the blood vessels in the temples.

As well as blurry vision, a person with GCA may also experience headaches.

According to the American College of Rheumatology, it only affects adults, typically those over the age of 50.

Treatment

Treatment with corticosteroids should begin as soon as possible, to help prevent permanent damage to vision.

Age-related macular degeneration (AMD) is a disease that can affect the retina, causing vision to become blurry.

According to the National Eye Institute, AMD is more common in older adults, and it can occur in one or both eyes.

Treatment

According to the National Eye Institute, there is no treatment for the early stages of AMD.

Lifestyle changes, such as giving up smoking, can help to slow its progression in the early stages.

If the disease progresses, a doctor may recommend injections of medications into the eye to improve symptoms, or laser treatment to slow vision loss.

Macular holes are small breaks or tears in the macula and typically affect adults over the age of 60.

People with a macular hole may notice distortion or blurriness when they look straight ahead, and straight lines may appear wavy.

Treatment

Some macular holes can repair themselves over time. However, in most cases, a doctor will recommend a surgical procedure called a vitrectomy.

The optic nerve connects the eye and the brain, transferring visual information from the retina to the brain.

Inflammation of the nerve can cause vision to become distorted or blurry.

Symptoms include:

  • pain around the eyes
  • loss of color vision
  • flashing lights

Treatment

Optic neuritis typically improves on its own. However, if symptoms are severe, a doctor may prescribe steroids to speed up the recovery.

Eating a healthful, balanced diet, staying hydrated, and not smoking may also help.

Some eye infections may require swift medical treatment, depending on the severity of the symptoms.

Keratitis

Keratitis is inflammation or infection of the cornea.

Symptoms include tearing, redness, irritation, and pain in the eye.

Treatment will depend on the underlying reason for the inflammation but may include antibiotic, antiviral, or antifungal medication in the form of eye drops or pills.

A person can learn more about keratitis here.

Conjunctivitis

Conjunctivitis is a bacterial or viral infection that affects the blood vessels in the membrane around the eyeball. Allergies can also cause conjunctivitis.

Symptoms may include blurry vision, eye discharge, and pink or red coloration of the whites of the eyes.

A doctor may prescribe topical or oral antibiotics for a bacterial infection or recommend OTC antihistamines for conjunctivitis triggered by an allergy.

There is no treatment for a viral infection.

Orbital cellulitis

Cellulitis is a bacterial or fungal infection that can affect the eyelids and the eyeball.

Symptoms may also include bulging of the eye, trouble moving the eye, and fever.

Treatment may include antibiotics or surgery to drain fluid from the eye.

Find out more about orbital cellulitis here.

Uveitis

Uveitis is inflammation of the uvea, the middle part of the eye, which also contains the iris.

Doctors call specific inflammation of the iris, iritis.

Bacterial or fungal infections typically cause uveitis.

Symptoms may include blurry vision, pain, and sensitivity to light, and it can affect one or both eyes.

Steroids can treat uveitis.

A person can learn more about uveitis here.

Migraine attacks are sometimes preceded by an aura, which can cause blurry vision and flashing lights.

Treatment

Treatment can involve prevention and relieving the symptoms during the migraine attack.

Prevention typically involves medications and behavioral changes.

Taking prescribed medication should help to ease symptoms.

A person can learn more about migraines relief here.

Using screens for a long time or focusing on something for an extended period without a break can cause eye strain.

This may lead to sudden blurry vision, itchy eyes, or headaches.

Taking regular breaks to rest your eyes will help relieve the symptoms.

People with sudden blurry vision and one or more of the following symptoms of a stroke, should call 911 or go to their nearest emergency room:

  • numbness or weakness in the face, leg, or arm, on one side of the body
  • confusion and difficulty speaking or understanding others
  • difficulty walking, dizziness, or lack of coordination
  • a severe headache

Vision loss or blurry vision accompanied by severe eye pain needs immediate treatment.

This will help to prevent further damage to the eye or help to identify a serious underlying health condition that has caused the blurry vision.

Not all causes of sudden blurry vision need urgent medical treatment.

However, if a person with sudden blurry vision thinks they may be having a stroke, is experiencing severe eye pain, or thinks they may have a detached retina, they should call 911 or go to their nearest emergency room.

People with unexplained sudden blurry vision should seek advice from a healthcare provider, ophthalmologist or optometrist, as soon as possible, even if the episode has passed.