Floaters are small dots or clouds that you may see moving across your vision. These may be noticed when looking at a blank background such as your ceiling or a blue sky and may also look like specks, lines, or cobwebs. Though floaters appear as though they are in front of your eye, they are actually inside the eye within the vitreous gel that fills the back of the eye. When light comes into the eye and comes into contact with the floaters, what you are seeing is the resulting shadow that is cast upon the retina.
Flashes of light or lightning streaks are visual phenomena that you may experience when the vitreous gel rubs or pulls on the retina. In some cases, it may be a symptom associated with a spasm of blood vessels or migraine.
Floaters and flashes of light become more common as we age. This is because the vitreous gel tends to change in consistency and thicken, shrink, or liquefy. While floaters and flashes do not always result in serious problems, in some cases they may be associated with a tear in the retina. A torn retina occurs when the shrinking vitreous gel pulls away from the wall of the eye. This may cause bleeding that can appear as new floaters. A torn retina is always a serious problem as it can lead to a retinal detachment requiring surgical repair.
If you notice new floaters, sudden flashes of light, or the appearance of a curtain covering some part of your vision, you should have a medical examination of your eyes to make sure that no damage has occurred to your retina.