Epi-Lasik
is a relatively new version of
surface ablation like
PRK that is more similar to
LASEK with some distinct advantages over
Lasik and
All-Laser Lasik. A
microkeratome with a blunt blade is utilized to mechanically
cleave the
epithelium
from the
Bowman’s membrane, leaving an expose area for
excimer
laser ablation. Epi-Lasik preserves the structural integrity
of the stroma and is heralded as minimizing patient discomfort when
compared to PRK and LASEK, shorten the length of time before visual
recovery, and reduce the incidence of
corneal
haze associated with other surface ablation procedures, such
as PRK and LASEK.
Laser refractive surgery has gone through an evolution beginning
in the early 1990s with PRK. PRK uses an excimer laser was fired
directly through the Bowman's layer and into the stromal layer of
the cornea to reshape its curvature effecting the refraction of
the patient. PRK tended to be very uncomfortable because of the
eye's wound response. Discomfort continues until the epithelium
grew back over the ablated area. Newer techniques limit patient
discomfort, but rarely eliminate discomfort completely. Additionally,
because of corneal haze due to wound response, the safe refractive
change with PRK was limited to approximately + 3 D to -6 D correction.
Newer techniques have expanded that range, but corneal haze is still
an issue that needs to be accommodated.
Lasik was the next evolution in laser refractive surgery. Lasik
involves a precise incision into the stromal layer of the cornea,
creating a flap. The flap is lifted exposing the stroma, where the
excimer laser ablates the tissue, reshaping the curvature from within.
Lasik effectively fools the cornea into not knowing that it has
surgery, so the procedure is virtually painless and given the control
of the depth of flap, Lasik has the ability to correct a much wider
range of correction (+5D to -15D). While Lasik solved many of the
issues surrounding PRK and widened the range of correction, it has
its own set of complications and refractive issues. The majority
of the complications relate to the flap itself and the optical aberrations,
which are attributed to it.
Ever in search of a better procedure, ophthalmology returned
to surface ablation solutions, primarily LASEK. The primary methodology
around this procedure was to attempt to separate the epithelial
layer from the top of the cornea, ablate the underlying tissue with
the excimer laser and replace the epithelium on top of the cornea
making it act as a biological bandage contact lens. This greatly
reduced the pain seen in PRK and eliminated the flap-related issues
plaguing Lasik. Although LASEK reportedly improved patient comfort
and reduced the probability of corneal haze, the alcohol solution
required to release the epithelial cells from the underlying cornea
mortally wounds all cells, delaying vision recovery and creating
an unstable epithelial layer until the cells are replaced.
Epi-Lasik attempts to provide the best of both Lasik and PRK/LASEK.
By using a blunt blade to lift the epithelium in a single sheet,
the epithelium is a much more viable entity. The repositioned epithelium
acts as a bandage while the underlying cornea heals. Although current
studies are inconclusive if patient outcomes are better with Epi-Lasik
when compared to PRK or LASEK, many studies have shown that the
surface ablation class of Epi-Lasik, LASEK, and PRK provides better
outcomes than Lasik and All-Laser Lasik.
If you are ready to choose a doctor to be evaluated for conventional
or custom
wavefront
Lasik,
All-Laser Lasik,
PRK,
LASEK,
Epi-Lasik,
NearVision CK,
RLE, or any
refractive surgery procedure, we highly recommend you consider
a doctor who has been evaluated and certified by the USAEyes
nonprofit organization. Locate a USAEyes Evaluated & Certified
Lasik Laser Eye Surgery Doctor.
If this article did not fully answer your questions, use our
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Video courtesy University of Illinois Eye & Ear Infirmary.
