Flashes of light in your vision, often called “strobing in eyes” or “ocular flashes,” can be concerning. While often harmless, they can also signal a serious underlying condition. This article explores common causes of ocular flashes, from eye-specific issues to broader health conditions, and when to seek medical attention.
What Are Ocular Flashes?
Ocular flashes are internal perceptions of light, not caused by external sources. People describe them as “shooting stars,” “lightning streaks,” or brief bursts like a camera flash. They can also appear as shimmering, zigzag lines, or sparkles. These flashes originate within the eye or brain, can affect one or both eyes, and vary in intensity and duration.
Eye-Specific Causes of Flashes
The most frequent cause of flashes is Posterior Vitreous Detachment (PVD). The vitreous, a gel-like substance filling the eyeball, is in contact with the retina. As a person ages, the vitreous gel liquefies and shrinks, pulling away from the retina. This tugging on the retina mechanically stimulates it, causing flashes. PVD is a common, age-related change and often occurs without vision loss.
While PVD is generally benign, forceful tugging can lead to serious complications. If the vitreous pulls too hard, it can create a retinal tear. Fluid can then pass through this tear, lifting the retina away from the back of the eye, a condition known as retinal detachment. Flashes with retinal tears or detachment may be sudden, persistent, or accompanied by new floaters. A shadow or “curtain” covering part of the visual field also indicates retinal detachment.
Other eye-specific causes include physical force on the retina. Rubbing eyes too hard or a blow to the eye can cause transient flashes. Sudden head movements can also trigger brief flashes. Any new onset of flashes should be evaluated to rule out retinal tear or detachment, as these conditions require prompt treatment to preserve vision.
Systemic Health Conditions Causing Flashes
Flashes of light in the eyes can also be a symptom of broader bodily conditions not directly related to the eye’s structure. Migraine aura is a common example, where visual disturbances occur, often before or during a headache. These visual auras can appear as shimmering zigzag lines, bright spots, or even blind spots that may expand across the visual field. Unlike flashes from retinal issues, migraine auras typically affect both eyes and last for about 10 to 30 minutes, though they can persist up to an hour. Migraine aura can occur even without a subsequent headache, a condition sometimes referred to as ophthalmic migraine.
Transient Ischemic Attack (TIA), sometimes called a “mini-stroke,” is another systemic cause that can lead to temporary visual disturbances, including flashes. A TIA occurs when there is a brief blockage of blood flow to the brain, which can affect the visual processing centers. Visual symptoms of a TIA can include temporary loss of vision in one or both eyes, blurry vision, or double vision. These symptoms usually resolve within minutes to a few hours, but a TIA serves as a warning sign of a potential future stroke and requires immediate medical attention.
Other systemic factors can also occasionally manifest with visual phenomena. Certain medication side effects, significant fluctuations in blood pressure, or even some types of seizures (epilepsy) can lead to temporary visual disturbances, including flashes. Conditions causing temporary disruptions in blood flow to the visual pathways can result in fleeting visual symptoms. These broader health conditions may signal a need for comprehensive medical evaluation.
Knowing When to Seek Medical Attention
Prompt medical evaluation by an eye care professional is advisable for any new or changing ocular flashes. A sudden onset of new flashes, especially if they are frequent or intense, warrants immediate attention. This urgency increases if flashes are accompanied by new floaters, particularly a “shower” of them.
Any flashes combined with a shadow, curtain, or partial vision loss are concerning symptoms that require emergency evaluation. Such visual changes can indicate a serious retinal tear or detachment, which, if left untreated, can lead to permanent vision loss. Flashes that occur after a head injury or eye trauma, or persistent flashes that do not resolve, should prompt an immediate visit to an eye doctor. Early diagnosis and treatment can significantly improve outcomes and help prevent irreversible vision impairment.