Lasik Laser
What are the various refractive surgeries?
The refractive power of the eye can be changed by any of the three approaches:
- Changing the curvature of the cornea: this is the most popular mode of refractive surgery.
- Removing the natural lens and replacing it with an artificial lens
of adequate power. As it is an invasive procedure and it also increases
the chances of retinal detachment in eyes with high myopia, it is not
recommended nowadays.
- Putting an additional artificial lens within the eye on top of the
existing natural lens: this technique is still not very popular as it
is also invasive and may increase the chances of cataract formation.
What are the ways of changing the curvature of cornea?
The commonly used methods for refractive surgery are:
- PhotoRefractive Keratotomy (PRK) : It is being used less commonly nowadays.
- Laser-Assisted In-Situ Keratomileusis (LASIK) :This is the most popular form of Laser treatment.
- LASEK (or Epi-LASIK) :This newer form of treatment may be suitable in some selected patients with very high power.
What is Excimer laser?
Excimer laser is Ultra Violet (UV) light energy of wavelength 193
microns. This laser breaks the chemical bonds within the molecules
(photoablation) with minimal thermal damage to the surrounding tissues.
Thus it is very precise and can remodel the cornea with an accuracy of
more than a thousandth of a millimeter.
How does Excimer laser correct the refractive error?
The effect of excimer laser on the cornea is very similar to grinding
of a glass lens to change its refractive power. In eyes with refractive
errors, excimer laser because of its high level of precision, can
change the shape of the cornea to change its refractive power to the
desired state and thus correcting the refractive error.
What is LASIK?
LASIK involves putting the PRK treatment not on the surface of the
cornea, but under a protective corneal flap. A very thin (about 0.16
mm) and precise flap is raised by a special instrument known as
microkeratome. The result is a corneal flap attached at one edge, the
hinge. The surgeon folds the flap to expose the inner stromal layer of
the cornea.
The excimer laser treatment is applied on this stromal bed to
remodel it. After this the flap is repositioned to its original
position and it does not require any suture. Since the corneal
epithelium has only been minimally disturbed, there is only mild
discomfort after the procedure.
What is Customised LASIK?
This is a special form of LASIK in which the treatment parameters
are customised for the particular patient, based not only on the
refractive error, but also on the corneal map of the eye and other
findings detected by special tests. This procedure tries to correct
aberrations, maintains normal shape of the cornea and gives better
night vision.
Who is a suitable candidate for LASIK laser surgery?
The person must be 18 years or older with a stable power. A contact
lens user must discontinue the use of contact lenses at least 2 weeks
before the procedure. A detailed eye checkup is done to look for
suitability for the procedure.
Before the Laser is done the eyes are checked with special machines to
determine the exact power, the corneal mapping is done and corneal
thickness is measured. In patients with high minus power, a special
retinal checkup is done for detecting any possible weak areas in the
retina, which may need to be treated before the LASIK is performed. The
LASIK laser is performed only after ruling out any contraindication and
confirming the suitability of the procedure.
What happens during the Laser surgery?
The LASIK surgery is done as an outpatient procedure and does not
require any admission. It is painless and is done after putting the
anesthetic drops and does not require any injections. The laser
procedure takes approximately 15-20 minutes for both eyes. After the
procedure, the patient can go back home after 20-30 minutes.
What are the complications of LASIK?
LASIK is a very safe procedure with a majority of patients
achieving very good results. However, since it is a surgical procedure,
it does carry some chances of complications as well, which would be
discussed with you before the surgery. The overall rate of significant
complications in LASIK is only of the order of 1-2%. Some of these
complications may be:
- Undercorrection or Overcorrection
- Glare and difficulty in night driving
- Flap complications, perforation
- Infection
- Scarring of the cornea
What are the precautions to be followed after LASIK, and when can one resume work?
After LASIK surgery one needs to avoid using cosmetics in and around
the eye for a week or two. One should also avoid wetting or rubbing the
eyes for some period. Use the medications regularly and report
immediately in case of any discomfort, redness, injury or any other
problem. There is no restriction in reading, watching TV, going for
walks etc. In majority of cases, routine office or simple household
work may be resumed in a day or two.
How are the results of refractive surgery?
Before undergoing any refractive surgery procedure, one must
realize that none of these procedures can guarantee you perfect vision
without glasses in all the cases. These surgeries are based on the
average calculations from a large population, but as different
individuals may respond differently to surgery, there might be some
variation in the outcome results obtained.
The aim is to decrease your dependence on glasses/contact lenses. The
reliability of the procedure is quite good in mild to moderate levels
of refractive errors, with most of people being able to carry out their
daily activities without glasses. But for high degrees of refractive
errors, the variation is more and some people may still need glasses,
though of much lesser power than before, to see clearly. Top
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