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 numerous or more prominent.
In most cases, floaters are part of the natural aging process. Floaters may look like cobwebs, squiggly lines, or floating bugs. They appear to be in front of the eye but are actually floating inside. As we age, the vitreous (the clear, gel-like substance that fills the inside of the eye) tends to shrink slightly, forming clumps within the eye. What you see as floaters are the shadows that 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 gentle tugging (or traction) of the vitreous gel on the retina. Flashes may look like twinkles, lightning streaks, or a flash of light from a camera.
Floaters sometimes get in the way of clear vision, often when reading. Try looking up and then down to move the floaters out of the way. While some floaters may remain, many of them will fade over time.
Floaters and flashes are sometimes associated with retinal tears. When the vitreous shrinks, it can pull on the retina and cause a tear. A torn retina is a serious problem. It can lead to a retinal detachment and blindness. Laser surgery or cryotherapy (freezing) is often used to seal retinal tears and prevent detachment.
If new floaters appear suddenly or you see sudden flashes of light, see an eye doctor immediately.