Flashes of light in your vision, medically known as photopsias, are often described as lightning streaks. These sensations originate within the eye or brain, indicating a disturbance in the visual system that prompts the brain to interpret non-light stimuli as light. Photopsias can vary in form, color, duration, and may occur in one or both eyes.
The Eye’s Internal Mechanics Behind Flashes
The perception of eye flashes primarily involves the interaction between the vitreous humor and the retina. The vitreous humor is a clear, gel-like substance filling the eye’s main cavity, helping it maintain its shape. The retina, a light-sensitive tissue lining the back of the eye, contains specialized cells called photoreceptors that convert light into electrical signals, which the brain interprets as images.
Flashes occur when something other than actual light stimulates the retina. As a person ages, the vitreous humor naturally shrinks and becomes more liquid. Tiny fibers within the vitreous are attached to the retina, and when the shrinking vitreous pulls on these attachments, it mechanically stimulates the photoreceptor cells. The retina translates this mechanical stimulation into electrical impulses, which the brain perceives as flashes of light.
Common Conditions Causing Eye Flashes
One common cause of eye flashes is posterior vitreous detachment (PVD), a natural age-related process where the vitreous gel separates from the retina. This separation typically occurs without issues, but the vitreous pulling on the retina can generate flashes, often seen as brief white or golden yellow streaks in peripheral vision. These flashes usually diminish and disappear once the vitreous fully detaches.
Flashes can also be a symptom of a retinal tear or detachment, which are more serious conditions. If the vitreous pulls hard enough, it can create a tear in the retina, allowing fluid to pass through and lift the retina, leading to detachment. These flashes are often described as sudden, repeated streaks of lightning.
Migraine aura, sometimes called ocular migraine, is another cause of visual disturbances, including flashes. These flashes are neurological, resulting from electrical or chemical waves spreading across the brain’s visual cortex, rather than mechanical stimulation of the retina. Migraine aura can manifest as shimmering zigzag lines, bright spots, or temporary blind spots, typically affecting both eyes and lasting 10 to 60 minutes. Other causes include eye trauma, inflammation, or certain medications.
When to Consult a Medical Professional
It is important to seek prompt medical attention from an ophthalmologist if you experience new or changing eye flashes. A sudden onset or increase in their number or intensity warrants immediate evaluation. These changes could signal a serious underlying condition like a retinal tear or detachment, which requires urgent treatment to preserve vision.
Additional indicators for concern include flashes accompanied by new floaters, especially a sudden “shower.” A shadow, curtain, or veil that appears in your field of vision is also a significant warning sign, potentially indicating a retinal detachment. Any flashes after head or eye trauma should be assessed by an eye care professional without delay. Early detection and treatment are important for managing these conditions and preventing permanent vision loss.