Your
laser treatment, whether
conventional or CustomVue, can be
delivered in a number of ways that
differ primarily on the layer of
the cornea that is treated and how
that layer is exposed.
With
the popular LASIK procedure, a microkeratome is used
to lift a "corneal flap" that includes the
epithelium, Bowman's membrane and a portion of the
deeper, underlying layer known as the stroma. The laser
treatment is then applied to the exposed corneal
stroma. Afterwards, the flap is repositioned over
the treated surface. Because the surface epithelium is
relatively undisturbed, LASIK is the most comfortable
laser procedure and
offers the most rapid healing.
Most LASIK flaps are still created
with the reliable mechanical microkeratome,
which has progressively improved since
LASIK started in 1993. Recently, however, two versions of a laser system (a.k.a.
"Intralase" or "All
Laser LASIK") have been developed to create the corneal flap. These units are new and their results are not yet proven to be any better than those of traditional keratomes, despite adding significant cost to the procedure.
The
PRK Procedure
Unlike
LASIK, with PRK, no flap is
created. Instead, the
epithelial cells over the
treatment area are loosened and removed,
and the laser treatment is
performed directly on Bowman's
membrane. In the Epi-LASEK
variant of the PRK procedure, an
attempt is made to put the
epithelial cells back into place
after the laser treatment, but
with standard PRK, no such attempt
is made, and the epithelium heals
when new cells grow in from the
periphery.
Because the surface epithelium is
disturbed, PRK is less comfortable
than LASIK and the eye heals more
slowly. After PRK, you will
need to wear a soft bandage
contact lens for three to five
days, until the epithelium is
completely healed. This is to
protect the cornea as it heals, as
well as to keep the eye more
comfortable. Your vision will improve daily, but it
can take as much as a week for it
to return to a functional level,
and several weeks or months for it
to reach its final clarity. For
this reason, PRK is
performed one eye at a time, with
at least a week in between
eyes. Postoperative
follow-up is essential to assess
the visual recovery.
