Seeing flashing lights in your eye could indicate many different health conditions. Treatment will depend on the underlying cause, but you’ll definitely want to see an eye doctor as soon as possible.

Have you noticed flashes or threads of light in the corners of your eye and wondered what’s going on? Flashes in your eye are a type of photopsia or vision disturbance.

Light flashes can happen in one or both of your eyes and have different shapes, colors, frequencies, and duration. There are many causes for this.

The retina is a thin, light-sensitive tissue that lines the back of the inside of your eye. It transmits electrical signals to your brain via the optic nerve. The retina’s job is to process the focused light that comes in through your pupil and let your brain convert this information into a picture.

The vitreous humor is a clear jelly-like fluid that takes up a large part of the back of your eye. It protects the retina and helps your eye maintain its shape.

The retina knows only one “language,” and that’s light. This means that anything stimulating the retina, including pushing or pulling on the retina, can lead to the transmission of a light impulse – even in a totally darkened room.

Tiny fibers float in the clear vitreous fluid; some are attached to the retina’s surface. When these fibers tug or pull on the retinal surface, it can cause flashes or light sparks from the friction.

Flashes of light in the eye are typically not a condition on their own. Instead, they tend to be a symptom of another condition.

According to the American Academy of Ophthalmology, seeing flashes of light in the corner of your eye can be caused by many different factors or conditions.

Some causes may be related to your eye health, while others may be related to other types of health conditions.

Eye-related conditions

Several types of eye-related conditions may cause light flashes to appear in the corner of your eye or field of vision. This includes:

  • Posterior vitreous detachment: This is one of the most common causes of light flashes in your eye. It typically happens as you get older. With posterior vitreous detachment, the vitreous humor detaches from the retina. If it happens too quickly, it can cause small flashes of light, usually in the corner of your vision. It can also cause floaters. This condition doesn’t usually require treatment.
  • Optic neuritis: Optic neuritis happens when the optic nerve becomes inflamed. This can be caused by an infection or a nerve-related disorder such as multiple sclerosis. Flashes of light can be a symptom of this condition.
  • Retinal detachment: Retinal detachment is a serious condition that can cause partial or complete vision loss. When this happens, the retina detaches, shifts, or moves away from the back wall of the eye.
  • Pressure on the retina: If you rub your eyes, cough too hard, or get hit on the head, you may notice light flashes due to extra pressure.
  • Injury: An injury directly to your eye may cause you to see flashes or “stars” due to pressure on the retina.

Other health conditions

Light flashes may also be a symptom of:

  • Occipital epilepsy: This rare type of seizure in the occipital lobe of the brain can cause visual flashes in the eye. It can be a sign of seizure activity. This is sometimes mistakenly diagnosed as a migraine aura. Typically, though, occipital epilepsy is shorter (seconds) compared to a migraine aura (minutes).
  • Migraine: Visual disturbances are common with a migraine aura. You may see flashes of light, zigzag lines, stars, or dots of light in your eyes. These symptoms usually go away within 60 minutes.
  • Transient ischemic attacks (TIAs): More commonly referred to as ministrokes, TIAs happen when a blood clot temporarily restricts blood flow to your brain. TIAs can cause visual disturbances, including flashes of light in your eyes.
  • Diabetes: Flashes of light or floaters can be a symptom of diabetic retinopathy.
  • Tumors: Tumors in different areas of the eyes or brain can generate flashes when you move your head or neck.

Medication side effects

Some medications may cause light flashes or floaters in your eyes.

This includes:

Retinal detachment is a medical emergency and requires immediate medical attention to prevent vision loss. If you have the following symptoms, get medical help right away:

  • sudden flashes of light, especially when you look to the side
  • partial vision loss or darkened vision
  • blurred vision
  • dizziness
  • other sudden vision-related problems

A TIA can often be a warning sign of a stroke. That’s why it’s important not to ignore the signs. If you notice any of the following symptoms, get medical attention as soon as possible:

  • weakness or numbness on one side of your body
  • slurred speech or difficulty talking or understanding others
  • visual disturbances or visual changes
  • dizziness
  • severe headache

Any serious injury to your eye also needs immediate medical attention.

Make an appointment to see an ophthalmologist, optometrist, or primary care physician if you:

  • have a sudden increase in flashes of light in your eye or eyes
  • notice an increase in the size and number of floaters
  • have a sudden change to your vision
  • have an increase in visual auras with migraine

A healthcare professional can determine the cause of the light flashes based on the type, duration, and location of these visual disturbances.

Flashes of light in your eye are typically a symptom of an issue related to your eyes or some other health condition. A comprehensive eye exam, including pupil dilation and retinal funduscopy, can help identify the reason for the flashes. The treatment will depend on the underlying cause

When you consult a healthcare professional, be sure to go over all the medications you’re currently taking. Some medications can cause vision-related side effects.

In some cases, as with optic neuritis, treating the cause of the inflammation or infection can stop the light flashes. Tears in the retina or retinal detachment may require surgery.

There’s no treatment for shrinking of the vitreous that normally occurs with age.

Are flashing lights a symptom of stroke?

Yes, flashing lights or “floaters” in your vision can signify a stroke. Other symptoms include blurred vision, dark spots, and vision changes that worsen over time. Seek emergency medical attention.

What are the symptoms of a ministroke in the eye?

A transient ischemic attack (TIA) or ministroke can cause sudden vision loss, blurred vision, double vision, and light sensitivity. These changes usually affect one eye only and are often painless. Seek immediate medical help.

What do retinal tear flashes look like?

Retinal tears or retinal detachment are often characterized by flashing lights, streaks of lightning, or stars in your line of sight. These flashes are often white or yellow and may be more noticeable in a dark room.

When should you be worried about flashing lights in your eyes?

It’s important to consult a healthcare professional anytime you experience a sudden, severe change in your vision. This is particularly true for visual disturbances that happen more than once or for an extended period.

Seek emergency medical attention if you experience vision loss.

A wide variety of issues can cause flashes of light. Some may be related to your eye, and some may be a symptom of another type of condition, such as migraine, epilepsy, diabetes, or TIAs.

To stay on top of your eye health, it’s important to visit an eye doctor for a checkup at least once a year.

Regular eye exams can help your healthcare professional determine if there have been any changes to your vision or the health of your eyes.