Permanent serious loss of vision following laser vision correction is extremely rare, as the procedure is not carried out inside the eye but on the outside.
Poor vision may be caused if an infection were to develop following the procedure; the risk of this occurring is approximately 1 in 10000. In the worst likely scenario, a form of corneal transplantation may be required to replace a damaged block of tissue in the cornea, restoring vision usually to driving standards. Problems that can lead to the need for transplantation include scarring after infection or an abnormal healing response, and an unstable corneal shape, also called corneal ectasia. These problems occur infrequently, and can often be corrected without transplant surgery.