Excimer Laser Vision Correction
The Excimer Laser is used to correct refractive errors for distance
vision, namely myopia, (short-sightedness), hyperopia (longsightedness)
and astigmatism either on it`s own or in combination with myopia
Patients who require reading glasses for near vision and for
whom no glasses or contact lenses are required for distance vision,
are not candidates for laser surgery.
The decision to proceed with Excimer Laser refractive surgery
is a personal one, provided the ophthalmic examination is appropriately
is the most common refractive problem affecting one in every four
South Africans. Myopia is caused by an eyeball which is too long
or a corneal curvature which is too steep. This in turn causes
light rays to focus in front of the retina resulting in blurred
Hyperopia the light rays are focused behind the retina, due to
an eyeball which is too short or the corneal curvature which is
too flat. This results in blurred distance vision, which worsens
Astigmatism causes a single focal point to separate into two focal
points that are both out of focus with respect to the retina.
The corneal surface distortion is similar to the shape of a rugby
ball. Astigmatism can occur in isolation or in association with
myopia or hyperopia.
Excimer Laser Procedure
Excimer Laser is the most advanced technology available for the
correction of "distance" refractive errors. The laser
is able to gently and precisely reshape the cornea to eliminate
refractive errors. It is a painless procedure requiring only local
anaesthetic eye drops.
The laser removes 0.25 microns of tissue per pulse and is unique
in its ability to remove thin layers of the cornea without affecting
the underlying layers. The corneal tissue undergoing treatment
is vapourised during the Laser induced photo-disruption of molecular
bonds. There is no heat nor explosive shock waves produced. Excimer
Laser procedure is performed as an outpatient procedure in a surgically
clean operating theatre and takes approximately 10 minutes per
eye. During the procedure the eyelids are kept open by means of
an eyelid speculum preventing involuntary blinking.
The Excimer Laser treatment reshapes the corneal curvature. In
Myopia the corneal curvature is flattened, in astigmatism a symmetrical
curvature is achieved and in Hyperopia the curvature is steepened.
The procedure results in light rays focusing precisely on the
The two Excimer Laser procedures used are Photorefractive Keratectomy
(PRK) and Laser-assisted- in-Situ-Keratomileusis (LASIK).
The laser beam is directly applied to the surface of the cornea
after the epithelium (outerskin) has been mechanically removed.
The cornea requires a contact lens for a few days whilst re-epithelization
takes place. The eye can be uncomfortable and painful during this
A Thin flap of cornea is cut and then lifted aside out of the
path of the ensuing laser beams. The treatment is then performed
on the exposed corneal bed. After the treatment is completed the
flap is replaced in its original position. Corneal factors account
for a strong adhesion of the flap to its bed and no sutures are
The corneal surface is intact which results in a painless nearly
immediate visual rehabilitation, without any risk of scarring.
The Lasik technique is considered the most advanced technique.
Many of our patients have occupational needs for improved visual
acuity (police, fire fighters, sportsmen and women to name a few).
Others simply have a desire to be independent of glasses or contact
To wake up and see independently of glasses not only improves
cosmesis but adds to one`s self-confidence.
LASIK Surgical Technique - External View - stage1
The microkeratome is used to produce a lamellar corneal flap.
This external oblique view of the eye shows the lamellar corneal
flap (F) being reflected (arrow) to expose the superficial corneal
LASIK Surgical Technique - External View - stage2
Once the corneal flap (F) is reflected, the stromal bed of the
cornea (S) is ablated to a predetermined amount using the excimer
LASIK Surgical Technique - External View - stage3
After the treatment is completed the corneal flap (F) is replaced
in its original position. Dr Cilliers was were among the first
refractive surgeons to perform Excimer Laser surgery in South
Who qualifies for surgery?
- Age 18 or older provided there has been stable corrected
vision within the past 2 years.
- No corneal nor retinal diseases
- Realistic expectations
- A full understanding of side effects
- A full understanding of risks ( serious vision threatening
complications can occur in less than 0.01 percent of patients
What can I expect following excimer laser procedure?
The vast majority of patients (96%) achieve at least "driver`s
licence" vision (20/40) or better within 12 hours of Laser
surgery. In the case of approximately 4% of patients, an additional
laser procedure (enhancement) is required to achieve the original
target of independence. This enhancement is performed at no extra
cost within the first year of surgery.
Remember that eyes can heal differently and consequently small
refractive differences between the eyes occur which usually do
not require optical correction. (This difference can occur in
normal sighted individuals).
During the fourth decade a persons near-vision deteriorates naturally
and independently of the laser treatment (presbyopia) and reading
glasses will be required.
Answers to Frequently Asked Questions
Is there pain during and after the procedure?
Slight discomfort is experienced during the procedure. The majority
of patients suffer a small measure of irritation and watering
of the eyes for a few hours after the treatment. A measure of
light sensitivity may be experienced for a few days.
How long does the procedure take?
About 10 to 15 minutes per eye.
How soon can I resume normal activity?
Functional vision returns within 12 hours. Patients in the "reading
glass" age will require temporary readers. Resumption of
sporting activities should be discussed with your ophthalmic surgeon.
Swimming is normally allowed after two weeks following surgery.
Is the laser safe?
When performed by an experienced Excimer Laser surgeon, the risks
are very low.
Is the procedure permanent?
Providing there is a stable refraction prior to the procedure,
the answer is "yes". The results cannot be guaranteed
in extreme old age due to the degeneration of eye tissue.
How will my vision after laser surgery compare with my vision
with contact lenses or glasses?
Most patients maintain the sharpness of their vision after laser
treatment. Approximately 1% loses one line of vision (slight loss
of contrast). This is more common in patients with extreme refractive
Will I experience side effects?
During the day some photophobia can be expected. Sunglasses cure
this problem. At night glare and haloes can be expected immediately
after the surgery. In most cases, these side-effects disappear
within six months. Some patients may still require spectacles
to improve night vision.
Can I still use contact lenses or glasses after the procedure?
What follow-ups can I expect?
You will be examined on day one post-operatively and again within
the first two to three weeks. Thereafter at intervals of three
to six and twelve months.
What are the long term effects?
The laser has been performed successfully since ± 1984
and is currently FDA approved. No long term adverse effects are
expected outside normal ageing or concurrent eye disease. If the
integrity of the eye remains intact, stability appears to be excellent.