Photopsia is the medical term for seeing flashes of light in your eyes. This visual sensation occurs when you perceive light that isn’t actually present in your environment. These flashes originate from within the eye or brain, rather than from external light sources. They can signify anything from common, harmless occurrences to serious underlying conditions.
Understanding What You See
Flashes of light can take various forms, such as streaks of lightning, zigzags, shimmering lights, or brief pops resembling flashbulbs, sparkles, white snow, or fuzz. These visual disturbances can appear in the periphery of your vision or across your entire visual field.
Common, Less Concerning Causes
Many instances of seeing flashing lights are benign and not a cause for concern. For example, pressing or vigorously rubbing your eyes can temporarily stimulate the retina, leading to the perception of light. The common experience of “seeing stars” after a mild blow to the eye or head is another instance of pressure-induced photopsia.
Another frequent, less serious cause involves the natural aging process of the eye’s gel-like vitreous humor. As people age, this vitreous can shrink and pull away from the retina, a process called posterior vitreous detachment (PVD). This pulling can irritate the retina, causing flashes of light, often described as lightning streaks or brief sparkles, especially in dim or peripheral vision. While PVD is a normal part of aging and usually harmless, it’s important to have it checked to ensure it’s not leading to more serious issues.
Standing up too quickly can also lead to temporary visual changes, including flashing lights or blurred vision. This phenomenon, orthostatic hypotension, occurs due to a sudden drop in blood pressure as gravity pulls blood downwards. The temporary reduction in blood flow to the brain and eyes causes these transient visual disturbances, often accompanied by dizziness or lightheadedness. These instances are brief, lasting only a few seconds, and resolve once blood flow normalizes.
Serious Underlying Conditions
While many causes of photopsia are harmless, flashing lights can also signal serious medical conditions that require prompt attention. A primary concern is a retinal tear, which occurs when the shrinking vitreous gel tugs on the retina, creating a break in the tissue. This pulling and tearing can cause repeated flashes of light, sometimes accompanied by new floaters. If left untreated, a retinal tear can progress to a retinal detachment, where the retina separates from its underlying support tissues.
Retinal detachment is a serious condition that can lead to permanent vision loss if not treated promptly. Symptoms often include a sudden increase in flashes and floaters, along with a “curtain” or “shadow” moving across the field of vision, or peripheral vision loss.
Migraines are another common cause of flashing lights, often as a visual aura. A migraine aura involves shimmering zigzag lines, bright spots, or blind spots that gradually expand across the visual field. These visual disturbances occur before a migraine headache, but can sometimes happen without one, a condition known as an acephalgic migraine. The visual aura lasts between 5 to 60 minutes.
Less common but serious causes include eye injuries, which can disturb the vitreous and retina, causing flashes. Internal eye hemorrhage, where blood leaks behind the retina, can also cause flashing lights and may lead to retinal detachment. Certain neurological conditions can also cause visual flashes.
When to Seek Medical Attention
Seek medical attention if you experience flashing lights, especially if they are new, sudden, or accompanied by other concerning symptoms. Any sudden increase in the frequency or intensity of flashes, particularly with new or increased floaters, warrants prompt evaluation. A “curtain” or “shadow” gradually moving across any part of your vision suggests a possible retinal tear or detachment.
Other warning signs include a sudden decrease in vision, eye pain, or flashes occurring after an eye injury. Early diagnosis and treatment are important for conditions like retinal detachment, as delaying care can lead to permanent vision loss. An eye care professional can perform a thorough examination to determine the cause and recommend appropriate treatment to protect your vision.