Epi-LASiK (Epithelial Laser In Situ
Keratomileusis) is usually performed as an outpatient
procedure using topical anesthesia with eyedrops. Your
ophthalmologist (Eye M.D.) uses an alcohol solution to loosen
and peel back the epithelium, the outermost layer of the cornea,
to expose the corneal tissue beneath it. A cool excimer laser is
used to permanently reshape the cornea, and the epithelium is
either placed back into position, where it will selfadhere, or
is removed completely, in which case the epithelium heals inward
from the corneal periphery in just a few days.
The cornea is a part of the eye that helps focus light to create
an image on the retina. It works in much the same way that the
lens of a camera focuses light to create an image on film. The
bending and focusing of light is also known as refraction.
Usually the shape of the cornea and the eye are not perfect and
the image on the retina is out-of-focus (blurred) or distorted.
These imperfections in the focusing power of the eye are called refractive
errors. There are three primary
types of refractive errors: They are myopia, hyperopia and astigmatism. Persons
with myopia, or
nearsightedness, have more difficulty seeing distant objects as clearly as near
objects. Persons with
hyperopia, or farsightedness, have more difficulty seeing near objects as
clearly as distant objects.
Astigmatism is a distortion of the image on the retina caused by irregularities
in the cornea or lens of
the eye. Combinations of myopia and astigmatism or hyperopia and astigmatism are
Light rays are focused
in front of the retina instead of directly on the retina
Light rays are not bent
enough to focus directly on the retina
Light rays are focused
at more than one point on the retina
The Cornea is reshaped
so light rays can focus directly on the retina
To treat nearsightedness, the cornea is made flatter by
removing tissue from the center of the cornea.
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.
To treat astigmatism, the cornea is made less oval
shaped. Astigmatism means that the eye has an oval or football
The laser reduces the oval shape making the focusing
ability clear in all directions. Astigmatism can be treated at
the same time as nearsightedness and farsightedness.
recovery after epi-LASiK is generally faster than in
PRK, a little faster than LASIK, but faster than
This type of laser vision correction does not
require any corneal incision at all. A mild alcohol solution is
placed on the corneal to loosen the top layer of tissue. Only
the most superficial layer of the cornea is gently brushed
aside. This thin flap is then replaced after the laser reshaping
is complete. Less tissue is removed than with traditional Lasik.
A contact lens is placed on the cornea shortly after surgery as
a bandage for several days to aid in the healing process. It
normally takes three to ten days for the epithelium to heal and
resurface the cornea. This healing time varies depending on a
number of factors such as the size of the area treated, the
health of the patient's cornea and the individual's own healing