“Floaters” and flashes are a common sight for many people. Floater is a catchall term for the specks, threads, or cobweb-like images that occasionally drift across the line of vision. Flashes are sparks or strands of light that flicker across the visual field. Both are usually harmless. But they can be a warning sign of trouble in the eye, especially when they suddenly appear or become more plentiful. That can be the sign of a tear in the retina, the patch of light-sensitive cells along the back of the eye that captures images and sends them to the brain. A retinal tear can lead to a retinal detachment, which can lead to permanent vision loss.