Eye flashes are visual disturbances, perceived as bright lights, flickering, or streaks, that do not originate from external sources. Also known as photopsias, they are signals from the retina interpreted as light. They often indicate changes within the eye.
What Eye Flashes Typically Look Like
Eye flashes appear as lightning streaks, sparks, shimmering lights, or brief pops like a camera flash. They can also look like zigzag lines or white snow. These visual sensations are typically white or sparkly, though they can sometimes appear colored. They may occur in the periphery or centrally, lasting seconds to minutes. Flashes are more noticeable in dark environments or when moving the eyes.
Common Causes of Eye Flashes
Most eye flashes arise from physical stimulation of the retina, the light-sensitive tissue at the back of the eye. A frequent cause is Posterior Vitreous Detachment (PVD), a natural aging process where the vitreous gel shrinks and pulls away from the retina. This tugging stimulates the retina, creating the perception of light. Flashes often diminish or cease as the vitreous fully detaches.
More serious causes involve the retina itself. If the vitreous gel pulls too strongly, it can lead to a retinal tear or, in severe cases, a retinal detachment. These conditions are significant causes of new or increased flashes. Another cause is migraine aura, which typically presents as shimmering, jagged lines or blind spots in both eyes, often preceding a headache. Eye trauma, such as a direct blow to the eye, can also trigger flashes due to sudden pressure on the retina.
When to Seek Medical Attention
While occasional eye flashes can be harmless, certain symptoms warrant prompt medical evaluation. A sudden onset of new flashes, or a significant increase in their number or intensity, should be immediately checked by an eye care professional. This is especially important if flashes are accompanied by a sudden increase in new floaters, or any loss of peripheral or central vision (e.g., a “curtain” or “shadow”). Flashes after head or eye trauma also require urgent medical attention. These signs can indicate a retinal tear or detachment, which requires timely treatment to preserve vision.
Distinguishing Flashes from Floaters
Eye flashes and floaters are distinct visual phenomena, though they often occur together and are sometimes confused. Flashes are perceptions of light, appearing as brief bursts or streaks from retinal stimulation. Floaters, conversely, are small spots, specks, lines, or cobweb-like shapes that drift across vision. They are tiny clumps of cells or debris within the vitreous gel that cast shadows on the retina. While both can signal vitreous changes, flashes involve light perception, and floaters involve seeing moving opacities.