Its advantages are that the central cornea is not affected, recovery is relatively rapid, and an experienced surgeon can be very accurate in correcting myopia. A laser is used to re-shape the corneal curvature to correct refractive errors. PRK is superior to RK in that the cornea is not permanently weakened, hyperopia can also be corrected with this procedure, and the procedure is largely computer-controlled which means that a surgeon's skills are not as much of a factor. It advantages include a much faster recovery, less pain, higher focusing errors can be treated, and less scarring results. There have been cases where the corneal flap becomes dislodged and lost, for example.
Refractive surgery is designed to correct distance vision only.
It does not change the normal aging process of the lens and presbyopia. Many people think that refractive surgery means that they will never need to wear glasses again. This is not true. Many web sites exist on refractive surgery. Describe how the eye changes its focusing power.