What Causes Light Flashes in the Eye?

Many conditions cause light flashes in the eye, known medically as photopsia. Seeing phantom light flashes is sometimes harmless, but this symptom might signal a serious disorder requiring urgent medical treatment. Photopsia most commonly originates within the eye itself, but can also occur due to disorders affecting visual nerve pathways in the brain. See you doctor if you experience light flashes to determine the cause and appropriate treatment, if needed.

Harmless Flashes

An occasional light flash in the eye can occur in healthy people without eye or medical problems. Most people discover during childhood that pressing or rubbing the eyes often elicits the appearance of sparkling or flashing lights, colors and shapes. This occurs because pressure on the eye mechanically stimulates the nerves of the retina, the vision-perceiving area at the back of the eye. Some people also experience brief photopsia with rapid eye movements. In an otherwise healthy young adult, these light flashes are typically harmless and rarely indicate an underlying eye or medical disorder.

Posterior Vitreous Detachment

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The vitreous is a gel-like substance that fills the back portion of the eye. Tiny fibers loosely attach the vitreous to the retina. As you age, the vitreous shrinks and can partially or completely detach from the retina, a condition called posterior vitreous detachment (PVD). The shrinking vitreous can pull on the retina as it detaches, stimulating the nerves and causing light flashes. PVD is the most common cause of the sudden appearance of eye light flashes, occurring in roughly 50 percent of people with the condition. Floaters also occur frequently with PVD.

Despite the rather scary name, PVD is a common age-related eye change that typically develops after age 60. People who are nearsighted have an increased risk for the condition. Vision loss rarely occurs with PVD and the light flashes usually disappear within 1 to 3 months. However, an eye exam is needed to check for complications, such as vitreous bleeding or a retinal tear.

Retinal Tear and Detachment

A retinal tear describes a tear in the retina of the eye. Roughly 14 percent of people with PVD experience a retinal tear, according to a study published in "JAMA" in November 2009. Other causes of retinal tears include eye injury or surgery, and diabetic eye disease, among others. When a retinal tear occurs, the vitreous can leak through the tear and lift the retina from the back of the eye, a condition called retinal detachment.

A retinal tear, with or without detachment, commonly causes sudden flashes of light in the affected eye 3. Other possible symptoms include floaters, spots or shadows, and blurry vision or partial vision loss. Urgent medical care is needed to prevent permanent vision loss with a retinal tear or detachment 3. Treatment options include surgery, laser treatment and cryopexy, a freezing technique that seals the retinal tear.

Other Causes

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Phantom light flashes can occur for a number of other reasons. For example, people with migraines who experience an aura often report flashing lights in one or both eyes as the headache develops. Less commonly, light flashes can occur without a subsequent headache, a condition called an ocular migraine. Other potential causes include: -- head trauma -- eye or brain tumor -- optic neuritis, or inflammation of the eye nerves -- macular degeneration, a disease of the retina -- low blood pressure or low blood sugar -- transient ischemic attack, or a mini-stroke -- medication toxicity, such as:

• digoxin (Lanoxin)
  
• quetiapine (Seroquel)
  
• paclitaxel (Taxol)

Warnings and Precautions

See your doctor as soon as possible if you experience unexplained light flashes. Seek immediate medical attention if you have existing eye disease, or the light flashes are accompanied by any warning signs or symptoms, including: -- blurred or reduced vision -- eye pain -- dizziness, weakness or mental confusion -- new or worsening headache -- nausea or vomiting

Reviewed and revised by: Tina M. St. John, M.D.