Laser Surgeries (surface laser=PRK and Lasik)
The described techniques have been approved by many
Ophthalmological and Scientific Societies; the text used is
commended by the B.S.C.R.S (Belgian Society of Cataract &
Refractive Surgery) in its brochures on Refractive Surgery, a
common work of a panel of Ophthalmologists. The B.S.C.R.S. has 426
members, all Ophthalmologists.
Both techniques (Lasik and PRK) are the major techniques in refractive
surgery. Refractive Surgery means the "surgery of the refractive
error", myopia, hyperopia
and/or astigmatism. These two
techniques do require a technically very advanced instrument:
the excimer laser. The excimer laser ablates (ablation means tissue
removal) in the central part of the cornea, for a myope, in the
periphery for an hyperope. The ablation zones can be "mixed"
for astigmatic correction.
 The latest excimer lasers are equipped with a very accurate
tracking system, which means that, if the patient cannot fixate
continuously a target light, the laser will “follow” the eye and
ensure that the treatment is properly centrated. This is critical
for the quality of vision. Iris recognition is used to check the
perfect adequation (alignment) of the eye during surgery, with the
measurements (corneal topography and aberrometry) taken before
surgery.
 In both technique (Lasik and PRK), the patient lies on a bed,
under the laser, and must fixate a flashing light during the treatment.
It is very important to stay quiet, as it facilitates the surgeon's
work. Here is a small description of the techniques:
- PRK: the ablation
happens on the surface of the cornea; the surgeon has to remove
the epithelium; this takes one minute, and then the laser can
treat on this "new surface". The treatment is short,
less than one minute, and is not painful. At the end, the eye
will be protected by a bandage contact lens, or by a patch.
Two variant of this technique: Epi-lasik (where the epithelium is
removed with a special instrument, called microkeratome, as in
Lasik, but equipped with a blunt blade), and Lasek, where the
epithelium is removed with an alcohol solution.
- Lasik: here
the ablation does not happen on the surface of the cornea, but
in the cornea itself. The first step is to realize a flap, with
a special instrument, called microkeratome, and to "open"
this flap, exactly like when opening the trunk of a car. The second
step is to ablate with the laser on the corneal bed. After the
ablation, the corneal flap is repositioned and the interface is
rinsed. The flap adheres by itself, so a few minutes are needed
to be sure that the flap is well in place. The patient is checked
30 minutes after the surgery to be sure that the flap adheres
nicely on the eye before he leaves the center. A protective eye-shield
is worn day and night for 3 days, and at night for one week. The
treatment is not painful.
It is also possible to use another laser, called Femtosecond
laser, to create the flap, instead of the microkeratome. This
relatively new instrument can be interesting for some patients.
Indications for laser
corrective surgery or refractive surgery
Risks of corneal refractive surgery
Reimbursment
Customized ablations
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