White flashes in the corner of the eye can be a startling experience, often prompting concern about eye health. This visual phenomenon, known as photopsia, can manifest as brief streaks of light, shimmering patterns, or what resembles camera flashes. While sometimes harmless, these flashes can also signal underlying conditions requiring prompt attention from an eye care professional.
Understanding How Eye Flashes Occur
The eye contains the vitreous humor, a clear, gel-like substance that fills the back of the eyeball and helps maintain its shape. This vitreous gel has tiny fibers attached to the retina, a light-sensitive tissue lining the inner back wall of the eye. The retina’s primary role is to convert light into electrical signals, which are then transmitted to the brain to form images.
As people age, the vitreous gel naturally changes, including liquefaction and shrinkage. This can cause the vitreous to pull away from the retina, a common event known as posterior vitreous detachment (PVD). When the shrinking vitreous tugs on the retina, the mechanical stimulation of its light-sensitive cells is interpreted by the brain as flashes of light. These flashes are the retina’s only “language” for communicating such stimulation.
Common Reasons for Seeing Flashes
A frequent cause of light flashes is posterior vitreous detachment (PVD). This natural, age-related process typically occurs in individuals over 60 and is often a benign condition that does not threaten vision. PVD flashes are usually brief white or golden yellow streaks, more noticeable in darker environments, and may diminish as the vitreous fully detaches.
Other less urgent factors can also induce flashes. Applying pressure to the eye, such as rubbing it too hard, can temporarily stimulate the retina and cause flashes or “stars.” Sudden head movements may also create momentary pressure or tugging on the retina, producing a fleeting sensation of light. While generally harmless, any new or persistent flashes warrant professional evaluation to rule out more serious issues.
Significant Causes Requiring Attention
Some causes of white flashes are more serious and require immediate medical evaluation. A retinal tear can occur if the vitreous gel pulls too forcefully on the retina during its separation, creating a break in the tissue. This tugging can lead to flashes, often described as lightning streaks or camera flashes, and may be accompanied by a sudden increase in floaters. If left untreated, fluid can pass through the tear, potentially leading to a retinal detachment.
Retinal detachment is a medical emergency where the retina separates from its underlying supportive tissue, resulting in significant vision loss if not addressed quickly. Symptoms include a sudden onset of flashes, a marked increase in floaters, and a dark shadow or “curtain” obscuring part of the visual field. A vitreous hemorrhage, bleeding into the vitreous gel often due to a retinal tear or abnormal blood vessels, can also cause flashes by casting shadows or stimulating the retina.
Migraine aura, sometimes called ocular migraine, can cause visual disturbances like flashes, zigzagging lines, or shimmering spots. Unlike retinal issues, these changes typically affect both eyes because they originate from electrical activity in the brain’s visual cortex, not within the eye itself. Migraine auras usually last between five minutes and an hour and may occur with or without a headache.
When to Consult a Doctor
Prompt medical attention is important for certain symptoms associated with white flashes. A sudden onset of new flashes, especially if persistent or increasing in number or intensity, should trigger an immediate visit to an eye care professional. New floaters, particularly a sudden shower, accompanying the flashes also signal a need for urgent evaluation. These combined symptoms can indicate a retinal tear or detachment.
Visual changes including a dark curtain or shadow moving across your vision, or a reduction in peripheral vision, require emergency care. Pain in the eye or sudden vision loss alongside flashes also necessitates immediate consultation. While many instances of flashes are benign, only a comprehensive eye examination can differentiate between a harmless event and a vision-threatening condition.
Diagnosis and Management
When consulting an eye doctor for flashes, a comprehensive dilated eye exam is typically performed. Eye drops widen the pupil, allowing the doctor to view the retina and vitreous gel. This examination helps determine if flashes are due to a common, non-serious condition like posterior vitreous detachment or a more serious issue such as a retinal tear or detachment. In some cases, additional imaging tests like optical coherence tomography (OCT) or ocular ultrasound may be used if the retina’s view is obstructed.
Management depends on the underlying cause. If posterior vitreous detachment is confirmed without complications, no specific treatment is usually needed, and flashes often become less noticeable over time. If a retinal tear is identified, laser photocoagulation or cryotherapy (freezing) may seal the tear and prevent progression to a full retinal detachment. These procedures create a scar around the tear. For a retinal detachment, surgical intervention like vitrectomy, scleral buckle, or pneumatic retinopexy may be necessary to reattach the retina and preserve vision.