Before the development of LASIK,
PRK (photorefractive keratectomy) used to be the
most common refractive surgery procedure. PRK was
invented in the early 1980s although the first FDA
approval of a laser for PRK was in 1995.
PRK is performed with an excimer laser, which uses a
cool ultraviolet light beam to precisely remove
small amounts of tissue from the surface of the
cornea. The goal of the laser procedure is to
reshape the cornea in order to correct the focusing
ability of the eye.
PRK takes just a few minutes and is done under
This type of laser vision correction does not
require any corneal incision at all. Only the most superficial
layer of the cornea is gently removed either with a laser or
with a tiny surgical brush. The excimer laser is then used to
reshape the deeper layers of the cornea, allowing for correction
of nearsightedness, farsightedness and astigmatism. After the
laser has completed the reshaping procedure, a protective
contact lens is then placed over the treated area to allow for
faster healing and less discomfort.
During PRK, less tissue is removed than with traditional Lasik.
Patients with thin corneas, dry eyes, large pupils, or those who
have had previous vision correction such as RK, may now have
laser vision correction safely performed.
PRK is used to safely and permanently correct nearsightedness,
farsightedness and astigmatism.
People who are nearsighted have difficulty seeing things at a
distance because their corneas are too steep. To treat
nearsightedness, the cornea is made flatter by removing tissue
from the center of the cornea.
Patients who are farsighted have difficulty seeing things up
close and also sometimes at a distance, because their corneas
are too flat. To treat farsightedness, the flat cornea is made
steeper by removing peripheral tissue in a ring shape on the
outer edges of the cornea. This steepens the central visual part
of the cornea.
Astigmatism means that the eye has an oval or football shape.
Patients with astigmatism have blurred vision both at a distance
and up close. The laser reduces the oval shape making the
focusing ability clear in all directions. The laser is used to
treat astigmatism at the same time as nearsightedness and
Patients generally have had marvelous results with PRK eye
surgery. The main benefit of PRK surgery is the removal of less
tissue than in traditional LASIK making it an option for
patients with very high prescriptions and/or thin corneas.