Floaters and Flashes
Small specks or clouds moving in your field of vision as you look at a blank wall or a clear blue sky are known as floaters. Most people have some floaters normally but do not notice them until they become more numerous or prominent.
In most cases, floaters are part of the natural aging process. Floaters look like cobwebs, squiggly lines, or floating bugs. They appear to be in front of the eye, but are actually floating inside the hollow vitreous cavity. As we age, the vitreous (a clear gel-like substance that fills the eye) tends to liquefy and separates from the retina forming clumps. What you see are the shadows these clumps cast on the retina, the light-sensitive nerve layer lining the back of the eye.
The appearance of flashing lights comes from the traction of the vitreous gel on the retina at the time of vitreous separation. Flashes look like twinkles or lightning streaks often in an arc-shape in the peripheral vision.
Floaters and flashes are sometimes associated with retinal tears. When the vitreous pulls on the retina it can cause a tear, which is a serious problem. Retinal tears can lead to retinal detachment and blindness if not treated. If new floaters appear suddenly or you see sudden flashes of light, see an ophthalmologist immediately.