What causes light flashes in the eye? what causes light flashes in the eye after laser surgery|?

Laser : Laser treatments to the eye may cause the vitreous jelly in the eye to move. The movement of the vitreous jelly may pull on the retina to cause flashing lights. If the flashing lights increase in frequency or intensity, and if you see new floaters, you should return to your ophthalmologist for an examination.

Normal or floaters: The gel that fills the inside of your can pull away from the retina-the part of your eye that "senses" light. Flashes are from traction-the gel pulling on the retina, which can cause (or indicate a retinal tear). This can lead to a blinding retinal detachment, sensed as a veil like sensation ultimately with vision loss. If you have flashes, floaters or a veil-see your eye doctor immediately.