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Refractive Laser Corneal Surgery |
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FAQs |
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What is Surface Photorefractive Keratectomy?
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Surface photorefractive
Keratectomy (SURFACE PRK), has been in
use all over the world since 1987 and has proven to
be safe and effective, particularly in the treatment
of myopia and astigmatism. However, when very high
refractive errors are treated by
SURFACE PRK, the
predictability of the procedure is lower with
increased occurrence of undesirable side effects.
Most of these adverse results appear to be due to
excessive corneal healing.
Since removal of corneal tissues from the surface is
a powerful stimulus for corneal healing, the
treatment of higher errors (requiring increased
removal of corneal tissue) produces poorer results. |
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A recent advance in the treatment of such high
refractive errors is a procedure termed Laser
In-Situ Keratomileusis (LASIK).
In this surgery, a flap of
superficial corneal tissue is cut using a
motorised blade. The
flap is lifted exposing the underlying corneal
stroma. The excimer laser is then used to perform
the appropriate tissue removal in the corneal bed.
At the conclusion of laser delivery, the corneal
flap is repositioned in its original position. The
flap adheres to the underlying corneal stroma
without the need for sutures. |
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Since the corneal epithelium is retained and corneal healing
occurs within the corneal layers, the safety and
predictability of the procedure is improved in eyes with
high refractive errors.
Cylindrical powers upto 4 diopters
can be corrected using laser –
Photoastigmatic Refractive Keratectomy (PARK) (Surface PARK/LASIK
PARK). |
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What does the procedure involve?
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Both SURFACE PRK and
LASIK are performed as
out-patient procedures using topical anaesthetic drops. You
will thus be, awake during the procedure.
You will lie face-up under the
laser. The surgeon will then enter
your refractive correction into the laser’s computer.
The surgeon will ask you to familiarise yourself with the
green and
red fixation lights inside the laser delivery tube.
One or two familiarisation sessions may then be performed to
help you get used to the sound and sensations of the laser. |
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After the initial familiarisation routine, the surgeon will
proceed to remove the corneal epithelium if a
SURFACE PRK procedure is
planned. If LASIK is being
performed, the surgeon will proceed with the creation of a
corneal flap. A sensation of pressure on the eye is felt
during the manoeuvres, but there is usually no pain. During
LASIK, a temporary blurring of
vision may be experienced when the
keratome (motorised blade) moves across the cornea.
It is important for you to help your surgeon during this and
subsequent steps by avoiding excessive eye movement. |
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Once the initial steps have been completed, the surgeon
activates the laser to perform the corneal sculpting. The
usual laser delivery time ranges from
15 to 45 seconds and
fixation on the laser target light is very important.
At the conclusion of the procedure, patients undergoing
SURFACE PRK will receive a
patch on the treated eye, while those undergoing
LASIK will have a
rigid plastic shield taped over
the operated eye. You should make arrangements for a friend
or relative to take you home after the procedure,
as no hospitalisation is required. |
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more... |
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