Laser surgery on the retina. Artwork showing laser surgery on a detached retina. The laser (white) is operating at a point where the retina (yellow) has peeled away and separated from the choroid, the layer of the eyeball it is normally attached to. The laser cauterizes small regions of the retina, sealing it back in place. Detachment of the retina can occur spontaneously, or as a result of injury or disease (diabetes & sickle cell anaemia). It is usually due to a tear in the retina, which causes fluid to accumulate behind the retina, lifting it up. Although painless, the condition results in a black drape falling across the patient's vision. Laser treatment normally restores vision.