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What Seeing Stars Means, and Why it Matters for Your Overall Health

Posted on June 28th, 2022

What’s happening in your brain and eyes when you see stars?

Whether you abruptly bump your head, stand up too fast, faint, or experience a migraine, “seeing stars,” is a common human experience. Although most people have a sense of what seeing stars means, the concept is more complicated than meets the eye. 

We’re delving into the mechanics of what happens to your brain and eyes when you see stars, flashes of light, halos, sparkles, and other streaks or specks of brightness that disrupt your vision.  

What is photopsia? 

The medical term for “seeing stars” is photopsia, a condition characterised by the presence of flashes of light or floaters in the field of vision. While photopsia can be harmless, it can also be indicative of various health problems. Symptoms include: 

- Flickers of light and eye flashes  

- Seeing sparks 

- Seeing colourful flashes of light  

Essentially, any unusual light source in the field of vision is considered photopsia. Generally, the flashes last for only a few seconds.  

How photopsia works 

In order to comprehend the ins and outs of photopsia, it’s important to have a basic understanding of the anatomy of your eyes. 

The retina—which is a layer of tissue at the back of the eye—is highly sensitive to light. Given that the eye is filled with gel-like fluid (called the vitreous), which attaches to the retina, when you rub your eyes, the gel fibres rub against the retina, triggering light flashes. In short, applying pressure to the eyes can cause temporary visual disturbances that are generally not cause for concern. 

It’s also useful to understand the anatomy of the brain. The occipital lobe, located in the back of the brain, works to decipher nerve signals communicated from your eye. Essentially, images travel from the retina through to the optical nerve in the brain, which the occipital lobe then processes, allowing you to see what’s before you.  

If your occipital lobe is impacted by a sudden fall or swift motion, your brain cells can send out electrical impulses, which can manifest as flashes of light or stars that are not actually there. In sum, all you are seeing is false flashes of light (called phosphenes), triggered by sudden pressure to the eye. 

What causes photopsia? 

Photopsia or “seeing stars” is a result of pressure being applied to your eyes when they are closed, which can trigger illusions of sparks, bright lights or flashes.  

That being said, photopsia can also be a sign of a serious medical condition, so it’s important to pay attention to how often the symptom arises, and for how long. It’s very important to be able to distinguish between when seeing stars is harmless—and when it’s not. 

When seeing stars isn’t scary  

There are certain things that will innately trigger photopsia, and in these cases, it’s completely harmless and nothing to worry about:  

- Rubbing your eyes: Directly applying pressure to your eye area can stimulate temporary streaks or blotches of light, which is perfectly normal and not cause for concern. 

- Sinus issues: Sneezing and coughing with your eyes tightly shut can cause light flashes. 

- Standing up suddenly: It’s very common to see stars when you stand suddenly, particularly if you’ve been lying down for a sustained period. The condition is called orthostatic hypotension, and it’s most common in children and young adults experiencing a growth spurt. 

- MRI scan and EEG testing: Both MRI (magnetic resonance imaging) scans and EEG (electroencephalogram) testing can stimulate the visual cortex and cause bursts of light. 

When seeing stars is scary  

As aforementioned, seeing stars is generally harmless, but there are certain instances where you should seek medical attention, particularly if photopsia is something you deal with often, or for more than a few seconds. 

- Migraines with an aura: Although migraines are typically characterised by a severe headache and throbbing pain, they can also sometimes be accompanied by a visual component. An aura is a sensory disturbance, which can include vision changes like flashes of light. While migraines are usually harmless, make sure to consult with your doctor if you suddenly experience visual symptoms, as it could be associated with something more serious, such as a retinal tear or stroke. 

- Concussion: A severe bang to the head can cause a concussion, a symptom of which is seeing stars. Concussions require immediate medical attention, so don’t ignore vision changes if you’ve been hit in the head. 

- Pregnancy: Seeing stars can be a symptom of preeclampsia during pregnancy, as those who experience the condition have high blood pressure, which can cause photopsia to occur. Preeclampsia comes with concerns, both for the mother and baby, and demands medical attention.  

- Retinal detachment: Emergency medical treatment is essential to prevent permanent damage from a retinal detachment, which occurs when the retina separates from the blood vessels that provide it with necessary oxygen. Naturally, retinal detachment can lead a patient to see stars and other abnormal light visions.  

- Wet macular degeneration: There are two types of AMD; wet and dry. Symptoms progress far faster with the wet form, which is caused by leaking from blood vessels in the eye. Seeing swirling light and flashes of colour is a common sign of this condition. 

- Diabetes: Vision changes are commonly associated with diabetes, which can sometimes lead to diabetic retinopathy. High blood sugar levels linked with diabetes can negatively impact blood vessels in the retina, and can spur sporadic light flashes and eye floaters.  

If you suspect you might be experiencing any of the aforementioned conditions, it is critical to seek medical attention as soon as possible. In these cases, seeing stars is associated with something serious.  

Even if you don’t believe you are suffering from a serious medical problem, if you experience photopsia for a prolonged period of time, consult with your optometrist, as it could also be a sign of infection or inflammation. Along with the above conditions, seeing stars could also indicate thyroid disease, blood vessel disease in the brain, optic neuritis, or a tumour.  

Treating and preventing photopsia 

Combating photopsia depends heavily on the underlying cause of the condition. In most cases, seeing stars is purely a symptom of sudden pressure to the eye area or head, and there isn’t much you can do to address it, other than letting it pass.  

In the case of photopsia that is associated with more severe illnesses, properly addressing the underlying issue should stave off vision disturbances.  

The best way to prevent photopsia is to ensure your ocular health remains optimal, which includes wearing eye protection when necessary, eating a balanced diet, and getting regular eye exams.  

On that note, we encourage you to book a comprehensive eye exam today at an FYidoctors clinic near you!