REFRACTIVE SURGERIES (Surgery to
remove need for prescription glasses)
If you have a refractive error,
such as nearsightedness (myopia), farsightedness (hyperopia), astigmatism or
presbyopia, refractive surgery is a method for correcting or improving your
vision.
There are various surgical
procedures for correcting or adjusting your eye's focusing ability by reshaping
the cornea, or clear, round dome at the front of your eye. Other procedures
involve implanting a lens inside your eye. Corneal procedures include incisional,
LASIK, SMILE, lamellar implantation, corneal collagen shrinkage, and collagen
crosslinking techniques.
Intraocular refractive
procedures include phakic intraocular lens implantation and Refractive lens
exchange with implantation of a monofocal, toric, multifocal, or accommodative
IOL.
There is no universally-accepted,
best method for correcting refractive errors. The best option for you should be
decided after a thorough examination and discussion with your ophthalmologist.
If you are considering refractive surgery, you and your ophthalmologist can
discuss your lifestyle and vision needs to determine the most appropriate
procedure for you.
The most widely performed type of
refractive surgery is LASIK (laser-assisted in situ keratomileusis), where a
laser is used to reshape the cornea.
Refractive surgery might be a
good option for you if you:
a. Want to decrease your
dependence on glasses or contact lenses;
b. Are free of eye disease;
c. Accept the inherent risks and
potential side effects of the procedure;
d. Understand that you could
still need glasses or contacts after the procedure to achieve your best vision;
e. Have an appropriate refractive
error.
· LASIK
· Phakic Intraocular Lens (ICL /
IPCL) Implantation
· Refractive Lens Exchange
· Bioptics
· SMILE
· Photorefractive keratectomy
(PRK)
· Radial keratotomy (RK)
· Astigmatic keratotomy (AK)
· Automated lamellar keratoplasty
(ALK)
· Laser thermal keratoplasty
(LTK)
· Conductive keratoplasty (CK)
· Intracorneal ring (Intacs)
· Laser-subepithelial
keratomileusis (LASEK)
· Epi-LASIK
LASIK is a surgical
procedure that uses a laser to correct nearsightedness, farsightedness, and/or
astigmatism. In LASIK, a thin flap in the cornea is created using either a
microkeratome blade or a femtosecond laser. The surgeon folds back the flap,
then removes some corneal tissue underneath using an excimer laser. The flap is
then laid back in place, covering the area where the corneal tissue was
removed. With nearsighted people, the goal of LASIK is to flatten the too-steep
cornea; with farsighted people, a steeper cornea is desired. LASIK can also
correct astigmatism by smoothing an irregular cornea into a more normal shape.
Phakic IOLs (intraocular
lenses) are an alternative to LASIK and PRK eye surgery for correcting
moderate to severe myopia (nearsightedness), and in some cases produce better
and more predictable vision outcomes than laser refractive surgery.
Phakic IOLs are clear implantable
lenses that are surgically placed either between the cornea and the iris (the
colored portion of your eye) or just behind the iris, without removing your
natural lens. Phakic lenses enable light to focus properly on the retina for
clearer vision without corrective eyewear.
Implantable lenses function like
contact lenses to correct nearsightedness. The difference is that phakic IOLs
work from within your eye instead of sitting on the surface of your eye.
Unlike contact lenses, you can't
feel a phakic intraocular lens in your eye (much like you don't feel a dental
filling for a cavity) and, apart from regular eye exams, phakic IOLs typically
do not require any maintenance.
Refractive Lens
Exchange, also called lens replacement surgery or clear lens
extraction, may be a better option than LASIK, PRK or phakic IOL refractive
surgery for people with presbyopia and high hyperopia (farsightedness).It
replaces your eye's clear natural lens with an artificial intraocular lens
(IOL) to correct your refractive error and achieve sharper focus, reducing your
need for reading glasses or bifocals.
Refractive lens exchange
typically is for people with presbyopia or extreme shortsightedness &
farsightedness, for whom LASIK, PRK or phakic IOL surgery generally are not
suitable. If you have both presbyopia and moderate to severe hyperopia, RLE may
be the only viable option for clear vision and minimal reliance on glasses
after refractive surgery.
The procedure for refractive lens
exchange is virtually identical to cataract surgery. The difference is that in
RLE, the lens being replaced is clear, rather than a cloudy lens due to a
cataract. As in cataract surgery, different types of lenses are available to
replace your natural lens, depending on your vision needs and the health of
your eyes.
Bioptics: In
refractive surgery, the cornea will always remain the limiting factor for the
correction of higher degrees of refractive error. The thickness, the
keratometry, and the biomechanical properties of the cornea all have their
influence on the final refractive outcome. It is of the utmost importance to
avoid glare and halos by choosing large enough optical zones and respecting the
mesopic pupil. In addition, to improve quality of vision, we must respect the
characteristics of the cornea.
For these reasons, bioptics is a powerful tool in the correction of high levels of ametropia. Combined phakic IOL implantation and LASIK allows the application of the maximal optical zones for both modalities.