Phosphenes are those images of light or color that you can see while your eye is closed. This can happen when you rub your eyes or when you cough. It can also be a signal that you have a more serious condition, like head trauma. Ask a healthcare provider for an assessment.
You may have experienced this: You have your eyes closed, but you can still somehow see a color or a flash of light.
This is the meaning of phosphenes — flashes of light with or without structure that you see when there isn’t an actual source of light entering into your eye. The most common occurrence of phosphenes results from pressure on the eyeball, but your retina or brain can stimulate them, as well.
Phosphenes are a form of photopsia, a visual phenomenon that includes eye flashers. Like many of these illusions, phosphenes may or may not indicate a medical issue.
You pronounce phosphenes as fah-sfeenz.
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People often describe phosphenes in terms of light even though there’s no light source. Some people say they’re glittery sparkles. Other people describe them as being like stars. Still, others see geometric shapes.
Many things can cause you to see phosphenes. Sometimes you can see them spontaneously. Possible causes of phosphenes range from rubbing your eyes to neurological diseases or ocular (eye) conditions.
You may have heard the expression “seeing stars.” If you hit your head or fall, you may see stars — bright flashes of light even when your eyes are closed. This reaction is similar to what you see when you rub your eyes and see light. Pressure on the eyeball can stimulate the retinal photoreceptor cells, causing the light you see.
Retinal damage can be a cause for phosphenes. You may see phosphenes if you have:
Phosphenes can also occur in certain neurological diseases, including:
You may experience phosphenes if you’re having radiation treatment for tumors in your eye, central nervous system or the head and neck area. These flashes of light usually happen during treatment and may persist after treatment as well.
Providers use transcranial magnetic stimulation (TMS) to treat some neurological conditions, such as depression. The electrical activity provoked by TMS can cause phosphenes.
You may see phosphenes for other reasons, including:
Some cases of phosphenes don’t appear to have a cause.
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Providers can’t treat phosphenes, but they may be able to treat the underlying cause of the phosphenes. It depends on what’s causing this visual disturbance to happen. Some cases of phosphenes might not need treatment, such as seeing light when you rub your closed eyes or straining while you cough.
It’s a good idea, though, to contact a healthcare provider if you see phosphenes at other times.
You may be able to prevent seeing phosphenes by managing other chronic diseases like diabetes, low blood pressure or migraines. Ask your provider for the best ways to do this.
You may be able to prevent head trauma by avoiding certain behaviors like fighting or riding bicycles or motorcycles without a helmet.
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If you see phosphenes frequently and you have other symptoms that worry you, like double vision (diplopia) or blurry vision, you should consult an eye care provider, such as an ophthalmologist. If you know you have diabetes, or if you’re seeing floaters in conjunction with the phosphenes, you should also consult an eye care provider.
Your eye care provider will begin by asking you questions about your medical history and your symptoms. They’ll then give you a thorough eye examination.
Phosphenes aren’t necessarily dangerous, but they can be a sign of other, more serious problems in some cases.
A note from Cleveland Clinic
Healthcare providers want the best for you. If you’re concerned about symptoms, including those that affect your vision, consult a provider. Finding out about problems early usually leads to improved treatment and prognosis. It’s better to speak to a provider and find out that a symptom is something normal than to ignore the symptom and find out that it’s related to a more serious condition.
Last reviewed on 04/05/2023.
Learn more about the Health Library and our editorial process.
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Cleveland Clinic is a non-profit academic medical center. Advertising on our site helps support our mission. We do not endorse non-Cleveland Clinic products or services. Policy