LASIK
>Important!
 |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
 |
|
Direct telephone 040 5551 0366
Ms Sheetal 93463 19982/040 3061 2131
Shaik Yousuf Arfath 040 3061 2101
Email: lasik@lvpei.org
Fax: 040 2354 8339 |
|
|
Important!
Although LASIK is an excellent procedure for low and moderate
refractive errors, it may not totally remove the need for
using glasses in everybody. However, it definitely decreases
the dependence on glasses for day to day work.
Possible
side effects
Laser surgery is very safe and effective. But in some patients
there could be side effects. Your doctor will be happy to
discuss these with you and clear your doubts before surgery.
Undercorrection/overcorrection:
Undercorrection may sometimes be planned intentionally or
may occur as an unintentional effect. As a result, the eye
remains short sighted even after the surgery. If the degree
of residual myopia is significant, the eye may be retreated
at a later date. Overcorrection can occur very rarely.
Glare/halo effect: You
may feel some sensitivity to light at night or in bright sunlight.
Sometimes in dim light, you may see a faded ghost image around
the sharp bright image. This will pass after the first few
days or weeks.
Decrease in contrast sensitivity:
Some people find that their night time vision has become a
bit dull. This happens because of a decrease in their ability
to discriminate between different contrast levels.
Flap complications:
Sometimes the anterior corneal flap that is made in LASIK
may not be complete if the keratome stops mid way because
of suction loss. In this situation the flap is repositioned
and ablation is deferred. The surgery is re-attempted after
three months. In rare instances, the flap may tear or become
detached.
Corneal ecstasia can
occur if the corneal thickness is less to begin with, or if
the cornea is thinned more than it can withstand with the
lasers. Therefore, persons having inadequate corneal thickness
are not suitable candidates for LASIK.
Other complications:
Serious complications like corneal infections, corneal edema,
corneal perforation etc., though possible, are extremely rare.
Top
Alternatives
to LASIK
For patients where the corneal thickness is not sufficient
for doctors to perform LASIK, there are other alternatives.
(Generally we do not do LASIK if the thickness is less than
470µm for spherical errors and less than 490µm
for cylindrical errors). In such cases the options are:
1. Photorefractive kertectomy
(PRK)
This was the most popular laser procedure for correcting refractive
errors before the advent of LASIK. Here the laser is applied
to the corneal surface. Since the epithelium (surface layer
of the cornea) is removed, this leads to greater activation
of inflammatory mediators and more healing. The problems of
excessive healing are haze (scar) that can decrease the clarity
of vision, and regression or refractive error returning due
to the addition of tissue. Haze and regressions are more if
the error is high. Generally PRK is recommended for cases
up to 6.0 diopters.
The problems encountered in
the early postoperative period with PRK are more pain (because
of epithelial defects), and delayed visual rehabilitation
as it takes 3-4 days for the epithelium to heal.
Early visual recovery, more
comfort, practically no haze and very little regression (not
in all cases) are the advantage of LASIK over PRK. We consider
doing PRK in eyes with borderline corneal thickness where
LASIK would be risky. Excessive ultraviolet exposure is a
risk factor for haze after PRK; this is a problem in Indian
subjects. After surgery, to minimize haze surgeons use ointments.
L V Prasad Eye Institute is one of the few places in India
that offers this procedure, and the results have been very
encouraging.
Top
2. Phakic intraocular lens
The Phakic IOL technique is recommended for patients with
moderate to severe myopia, i.e., very high refractive powers
(nearsightedness). It is used safely and effectively for very
nearsighted people who are tired of wearing thick glasses
and are not suitable for customised LASIK, due to very low
corneal thickness or flat corneas.
In this procedure an intraocular
lens, (made of biocompatible material that has been tested
and proven fit for implantation for over 50 years), is fixed
in front of the natural clear lens — behind the cornea and
on top of the iris. The word ‘phakic’ means that the natural
crystalline lens is left in the eye. This is important because
the natural lens plays an important role in helping the eye
adjust between seeing objects that are near and far. This
gives the eye another focusing lens that provides high-quality,
high-definition vision like a normal eye.
Phakic IOL is performed as
an outpatient procedure that takes 15 – 30 minutes. Usually
one eye is treated at a time. The patient is administered
eye drops to reduce the size of the pupil. The doctor uses
an instrument to comfortably hold the eyelids open during
the procedure. A local anesthetic is given to sedate the eye,
so the procedure is virtually painless. A small incision is
made in the cornea and the phakic IOL is centered in front
of the pupil, and is gently attached to the iris to hold the
lens in place. The incision is closed with microscopic stitches
that dissolve on their own.
Three types of lenses are used
for this purpose: anterior chamber, iris fixated, and posterior
chamber. The quality of vision is usually very good in patients
after phakic IOL as compared to those with LASIK. The patient
cannot feel the implanted lens.
Phakic IOL does not change
the natural appearance of the face and does not require any
special care or maintenance. Although it is intended to be
permanent, the procedure is reversible if desired. The implanted
lens can be removed any time, as the surgery does not affect
the important natural structures of the eye.
Top
3. Clear
lens extraction (Refractive lens exchange) with negative intraocular
lens implantation
We do not consider this option in myopes as literature has
suggested increased incidence of retinal detachment after
removal of the lens. We do not recommend this procedure in
young hyperopes, though the incidence of retinal detachment
is less in hyperopia. There is increased risk of posterior
capsular opacification in young individuals. Refractive lens
exchange with multifocal or monofocal intraocular lens is
recommended for high hyperopes over +5 D after the eye of
40 years.
In patients with high power,
low corneal thickness, or a flat cornea, LASIK can cause complications
or lead to reduced quality of vision. Phakic IOL is the recommended
treatment here, where an intraocular lens is fixed in front
of natural clear lens. Based on the position of the lenses
three types of lenses are used: Anterior chamber, Iris fixated,
and Posterior chamber.
As compared to LASIK the quality
of vision is better with phakic IOL and high power can be
corrected.
Top
4) Astigmatic cataract surgery
and multifocal lenses
Cataract surgery has become a refractive procedure now. Normally
a monofocal intraocular lens (IOL) is fixed in the normal
position of clear lens. The power of intraocular lens chosen
in for distance or intermediate vision and patient requires
glasses for reading. Multifocal IOL is an attractive option.
Hence the lens has multiple zones or rings which can focus
light for distance, intermediate and near vision. There are
two broad types. refractive bifocals (e.g. Ceeon bifocal)
and refractive multifocal (e.g. array). The purpose of this
IOL is to give patients freedom from spectacles for near and
distance vision. Patients do require a little additional power
(plus lens) for reading print. The problems include decrease
in contrast as all rays do not focus to a point) and glare
while driving in highways. To derive maximum benefit, the
astigmatism must be corrected by applying cuts on the cornea
(relaxing incision) or by laser treatment
Top
|
