Photopsia describes a visual disturbance commonly referred to as "seeing stars." It can occur when temporary pressure is placed on the retina of the eye (such as when you sneeze hard), causing momentary flashes of light in the absence of a light source. You might see sparkles, prisms, or streaks of light that look like lightning bolts.
Photopsia can also occur with a migraine headache, stress, brain-related circulation problems, or conditions affecting the retina or the gel-like substance inside the eye called the vitreous.
This article describes some of the possible causes of photopsia, both common and uncommon, and what can be done to treat these conditions.
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Why Am I Seeing Stars?
When the lining in the back of your eye—called the retina—senses light, it sends messages to the optic nerve. The optic nerve then relays these messages to the brain, which identifies the image.
When you are seeing stars or sparkles, something other than visible light is stimulating the retina. These false flashes are known as phosphenes.
Phosphenes can be triggered by pressing the eyes, which shifts the vitreous and compresses the retina. They can also happen when nerve cells (neurons) in the eye or brain are abnormally stimulated.
Pressure on your eyes is the most common cause of photopsia. For example, you might see stars when you:
- Rub your eyes excessively
- Sneeze hard
- Have a coughing fit
- Strain on the toilet
- Vomit
The visual disturbance usually only lasts for a few seconds and is not a health concern.
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Common Causes of Seeing Stars
When you see stars for a prolonged period or frequently, there are a number of possible causes. Here are some of the least serious explanations:
Posterior Vitreous Detachment
Posterior vitreous detachment (PVD) is a common condition caused by aging that affects the vitreous in your eyeballs.
This jelly-like substance is attached to the retina and helps keep the eyeball plump. With normal aging, the vitreous can start to shrink and may occasionally tug on the retina, causing you to see stars, floaters, or flashes of light. These disturbances usually occur at the outer edge of your field of vision (called your peripheral vision).
As PVD is a normal part of aging, no specific treatment is needed. Rare complications such as retinal detachment or tears may require urgent surgery.
Migraines
Seeing stars is also common with migraine headaches. Referred to as a migraine with aura, these disturbances typically last 20 to 30 minutes, causing a variety of visual disturbances like:
- Rainbow-like prisms
- Flashes of light
- Stars or sparkles
- Zig-zag lines
- Blind spots
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With some migraines, a visual aura can happen without pain. These are called ocular migraines and can affect either one or both eyes.
Anxiety
Photopsia can also occur with extreme stress. With anxiety, your body will release a hormone called cortisol that triggers the "fight-or-flight response." This is the response that helps you face a perceived or actual threat.
In addition to giving you a burst of energy, the fight-or-flight response causes the dilation (widening) of the pupils so you can see clearly in the dark. When this happens, the sudden dilation can shift the vitreous and trigger photopsia.
Stress-induced photopsia mainly affects middle-aged people who often have aging-related eye conditions.
One example is retinitis pigmentosa (RP), a rare eye disease mainly affecting adults in their 40s. Studies suggest that stress is one of the three things (alongside fatigue and bright light) that trigger photopsia in this group, causing:
- Quick flashes of light
- Bright dots or semi-circles
- A static-like burst of light
- Fluorescent flashes
According to the American Academy of Ophthalmology, stress can also visual disturbances in people with eye diseases like glaucoma or dry eye syndrome.
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Serious Causes of Photopsia
Sometimes a more serious condition can cause you to see stars. In such cases, photopsia may serve as a warning sign of a disease that has not yet been diagnosed.
Retinal Detachment
You may see stars, flashes, or bands of light if you have retinal detachment. This is a medical emergency in which the retina pulls away from its normal position in the eye. Left untreated, a detached retina can lead to permanent vision loss.
The symptoms of retinal detachment include:
- Flashes or sparkles of light in one or both eyes
- A dark shadow covering part of your field of vision
- An increase in floaters (dark spots or lines that float across our field of vision)
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Brain-Related Problems
While less common, seeing stars may be a sign of a problem in parts of the brain, including the occipital lobe, that regulates vision.
Example includes:
- Cerebrovascular disease: This is a group of conditions like stroke, brain bleeds, and brain aneurysms that compromise blood circulation in the brain. If the blood vessel servicing the occipital lobe is affected, photopsia may be an early sign.
- Postural hypotension: Also known as orthostatic hypotension, this is the sudden drop in blood pressure as you stand or rise quickly. The steep decline in blood to the brain can often trigger photopsia.
- Concussion: This isa mild traumatic injury to the head that affects brain function. The symptoms are usually short-lived but may involve "seeing stars" along with headaches and a temporary loss of memory or balance.
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Wet Macular Degeneration
Wet macular degeneration is an advanced form of age-related macular degeneration (AMD), a condition characterized by the progressive loss of central vision.
With wet macular degeneration, abnormal blood vessels grow under the part of the eye that helps you see fine detail, called the macula. This damages the macula far quicker than an earlier stage of the disease, called dry macular degeneration.
People with wet AMD frequently experience visual distortions, such as seeing sparkles of light or objects that suddenly appear to bend and distort.
Diabetic Retinopathy
Some people with untreated diabetes may develop diabetic retinopathy, a condition that occurs when high blood sugar damages tiny blood vessels in the retina. These vessels can leak blood and other fluids into the macula, causing blurred vision, tunnel vision, and even double vision.
The leakage can also increase pressure inside the eyeball, compressing the retina and causing visual disturbances like sparkles of glitter-like specks of light.
Diabetic retinopathy is a serious condition that can cause extreme vision loss if the blood sugar is not brought under control.
Preeclampsia
Preeclampsia is persistent high blood pressure that develops during pregnancy, usually after week 20. In addition to headaches and abdominal pain, people with preeclampsia often experience blurred vision or flashing lights. This may be due to increased pressures placed on the blood vessels servicing the retina.
Visual disturbances are often the first signs of preeclampsia and may serve as a red flag for this potentially life-threatening pregnancy complication.
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Treatment for Seeing Sparkles of Light
The treatment of photopsia can vary based on what is causing it. In some cases, photopsia is treated directly; in others, treating the underlying cause will help clear the visual disturbances.
Here are some examples:
- Posterior vitreous detachment: No treatment is needed if the retina is undamaged. If the retina is damaged, laser therapy or cryopexy (intense cold therapy) may be needed.
- Migraine: Options include over-the-counter and prescription pain medications as well as lifestyle changes (such as losing weight and stress management).
- Anxiety: Stress reduction techniques like yoga, meditation, and deep breathing can be practiced regularly or as needed. Anxiolytic drugs may be prescribed to people with chronic anxiety.
- Retinal disorders: Options include laser therapy, cryotherapy (freezing), and pneumatic retinopexy (involving an injection of gas into the eyeball to move the retina into place).
- Cerebrovascular disease: Medications like ACE inhibitors and calcium channel blockers can help reduce blood pressure along with diet, exercise, and weight loss.
- Postural hypotension: Severe cases may benefit from improved hydration, routine exercise, compression socks, and increased salt to better normalize blood pressure.
- Concussion: Getting plenty of rest for at least a couple of days is the main form of treatment for concussion. OTC pain relievers can also help.
- Preeclampsia: Medications may be used to help lower your blood pressure. Delivery may be recommended if the condition becomes dangerous.
Summary
Seeing sparkles of light and similar visual disturbances is known as photopsia. The individual flashes of light are called phosphenes.
Usually, seeing stars is due to temporary pressure on the eye. This is typically harmless and only lasts for a few seconds. However, if you see stars often or they last for a long time, see your provider. You may need treatment for an underlying cause like migraine or a retinal disorder.