Both the methods are used as refractive error correction method for
myopia, hyperopia, astigmatism and presbyopia. Both PRK and LASIK
are outpatient procedures that last for about 15 minutes per eye.
While both procedures offer excellent and comparable results, there
are some significant differences between PRK and LASIK. They
include.
The procedure:
The chief difference between PRK and LASIK is in its surgical
procedure. Photorefractive Keratectomy or PRK is a procedure in
which, refractive vision correction is performed on the cornea’s
surface. The front surface of the cornea is carved by the excimer
laser. The surface layer known as the corneal epithelium is gently
removed by the surgeon, which is regenerated within a few days.
LASIK offers refractive vision correction to be performed under
corneal flap. Laser In Situ Keratomileusis or LASIK is a procedure
that uses the excimer laser to reshape the cornea. A surgical
instrument known as microkeratome creates a flap on corneal tissue
that is attached by a hinge. The flap is gently pulled back and the
corneal stroma is exposed. Once the cornea is treated by the laser
and the cells are vapourised, the flap is replaced in its usual
position.
Recovery:
Patients, on whom PRK is performed, start improving in three days
time; while in LASIK, patients may recover on the same or the next
day.
Remarkably, there is a more rapid improvement in vision and
decreased discomfort with LASIK since the surface epithelial cells
have been preserved and do not need to grow again. This is
indisputably the reason that LASIK has become the most preferable
corrective surgery for both doctors and patients. However, in some
patients, PRK is a safer alternative to LASIK that may promise
better outcomes. Patients who might benefit from PRK include those
with less corneal tissue or in some patients with corneal
irregularities or scars.
Post surgical uneasiness:
The post-operative discomfort may vary in PRK patients. Some feel
pretty good while others feel the pain more because of scratchiness.
The discomfort is minimal, as compared to PRK, after a LASIK surgery
is performed.
Benefits:
In PRK there is less risk of dry eye, long term output same or
better than with Lasik, 20/20 vision or better is usually achieved.
In LASIK, there is almost no pain, better visual quality, typically
20/20 is achieved, immediate clear vision can be obtained, follow-up
developments are easier if needed.
Risks Involved:
Since PRK requires more healing time than LASIK, the pain may cause
complications after the surgery. The long-term outcomes may not be
well established. There is a risk involved of an increase in the
higher order aberrations which may lead to astigmatism.
Patients with thinner corneas may suffer less than ideal results, in
LASIK surgery. Uneven flap edges may lead to higher order aberration
or astigmatism. Post operational treatment is required in almost 5%
of the cases.
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