Flashes in the field of vision may be alarming, especially if a person has not experienced this before. Many people describe these flashes as “seeing stars.” The stars may look like fireworks, lightning bolts, or camera flashes.

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Various issues may cause a person to see stars, and many of them are no cause for concern. An isolated flash of light is usually harmless.

However, if this symptom becomes frequent or severe, a person should speak with an eye doctor right away.

Keep reading to learn more about the causes of seeing stars, how flashes differ from floaters, and how to maintain good eye health.

A person typically sees stars, sparkles, or flashes of light because of a disturbance in the retina or brain.

The retina is a lining of cells that sits at the back of the eye and sends messages to the brain when it detects light. This part of the eye sees light, but it does not see colors or shapes. A special gel called the vitreous humor sits in front of the retina to protect it.

Either the retina becoming inflamed or the vitreous gel moving around or shrinking can stimulate the retina, causing it to send signals to the brain. The brain interprets these signals as light, even if no external light source exists.

In addition, if something disrupts the electrical activity in the brain, it may send false signals, making a person think that they see stars.

People sometimes describe these temporary bursts of light as sparkles, streaks, or flashes, which appear and fade very quickly. On the other hand, bright spots or patches that appear and stay in place for a longer period may be due to another condition.

The following are the most common causes of disruptions in the brain or retina that could lead to a person seeing stars:

A blow to the head

Cartoons have portrayed this phenomenon — where impact to the head causes a person to see stars — for many years.

The back of the brain contains the occipital lobe, which is the part of the brain that processes visual information. A knock to this area can result in the brain sending out electrical signals that resemble light.

Getting hit in the eye can also cause sparks or flashes of light because it bumps the retina, which becomes stimulated and sends light signals to the brain. Gently rubbing closed eyes is a way to experience this phenomenon without injury.

Migraine

Migraine episodes can cause changes in vision, including seeing stars, sparkles, or flashes. They can also cause dark spots, heat-like waves, tunnel vision, or zigzagging lines.

In severe cases, the vision changes may include temporary blindness. Retinal disturbances or decreased blood flow to the retina may cause these symptoms.

These changes typically occur in both eyes, and experts believe that they result from abnormal electrical signals in the brain. If the vision changes happen before a headache, the condition is called migraine with aura. If they happen without a headache, it is called an ophthalmic migraine.

If the vision changes happen in only one eye, the person may have a retinal migraine. This can be a sign of a serious condition, so a person should contact a doctor immediately.

Other typical migraine symptoms include:

  • a throbbing and severe headache
  • sensitivity to light and sound
  • nausea
  • dizziness

Movement in the eye’s vitreous gel

The vitreous gel that is in front of the retina can move around, sometimes pulling on the retina itself. As a result, the retina sends light signals to the brain, causing sparkles, stars, or flashes of light to appear in the field of vision.

Movement or changes in the vitreous gel become more common as people age.

Although typically harmless, these flashes could signal a serious issue if they:

  • happen frequently and regularly
  • come on suddenly and severely
  • occur alongside other vision changes, such as new floaters or cloudiness

Retinal detachment or torn retina

Sometimes, the vitreous gel pulls on the retina hard enough to cause damage. It may tear the retina or detach it from the back of the eye.

If this happens, a person may see:

Risk factors for retinal detachment or tearing include:

  • being over the age of 40 years
  • a previous retinal detachment or torn retina, or a history of lattice degeneration
  • being very nearsighted
  • previous cataract surgery
  • having another eye disease, disorder, or injury to the eye

A torn or detached retina needs emergency medical care, as it can lead to blindness if it goes untreated. Laser treatment or surgery can correct it.

It is important not to confuse flashes of light or seeing stars or sparkles with seeing floaters. Although these symptoms can co-occur, they have different causes.

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Seeing stars in vision is a common occurrence, but can also be a sign of a medical condition.
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Floaters may look like shadows, lines, or dots that move across a person’s field of vision. Possible causes include tiny blood vessels bursting in the eye or protein clumps or cells in the vitreous humor.

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Light flashes in vision can be caused by many medical problems, such as migraine, retina problems, or even blood pressure problems. Jena Ardell/Getty Images

Floaters are typically harmless and become common as a person ages. However, a person should still discuss the floaters with an eye doctor, especially if they happen frequently or come on suddenly.

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An example of floaters in vision.
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A person can take steps to help keep their eyes and vision healthy. These may include:

  • getting regular eye exams with dilation, even in the absence of vision problems, to help catch any potential problems early
  • being aware of any existing health conditions or family medical history that may affect the eyes
  • exercising regularly and eating a balanced diet
  • quitting smoking, if applicable, or avoiding secondhand smoke where possible
  • wearing sunglasses to protect the eyes from the sun, even on cloudy days
  • resting the eyes when using a computer by turning away from the screen every 20 minutes and looking at something 20 feet away for 20 seconds
  • avoiding touching contact lenses without first washing the hands
  • disinfecting contact lenses and replacing them often

The American Academy of Ophthalmology recommends that people get a comprehensive eye exam by the age of 40 years, even if they have no other health problems. Factors that increase people’s risk of eye problems include diabetes, high blood pressure, and a family history of eye disease.

Regular checkups with an eye doctor provide the opportunity to mention any stars, sparkles, or flashes in the field of vision and to discuss any tests or treatments.

Seeing occasional flashes, sparkles, or stars in the field of vision is usually not an indication of an underlying health problem.

Many people find that seeing stars happens only occasionally and that their eyes are otherwise healthy. Seeing stars may occur more often with age.

However, seeing flashes frequently can indicate an eye problem that needs medical treatment. If a person experiences a rapid onset of flashes, stars, or any other vision changes, they should seek medical care right away.