Potential Risks of the Excimer Laser Procedure
It is essential that you understand as much as possible about
the risks associated with the excimer laser procedure. The risk
of having a serious vision-threatening complication is much less
than 1%, however, the excimer laser procedure, like all surgical
procedures, has limitations and risks.
Everyone fears losing their vision. NO cases of blindness
have ever been reported from either the PRK or LASIK procedures.
There are some specific side effects and risks you may encounter
1. PAIN -- There is no pain or discomfort during the procedure
itself. With new techniques, as few as 10% of patients have pain
post-surgically, which is treated with medications for 1-2 days.
Most patients experience only some irritation, light sensitivity,
and watering of their eyes for a few days.
2. INFECTION -- This is probably the greatest risk during
the first 48-72 hours post-surgically (~0.2%). You will receive
antibiotic eye drops before and after the procedure. The risk
of infection is lower than 2/1000, and most infections are treated
and eliminated. A severe enough infection can produce scarring
which reduce sharpness of vision. If this occurs, an 'enhancement
procedure' may be required to eliminate or reduce the scar tissue.
3. NIGHT GLARE -- Like most forms of eye surgery, the excimer
laser can cause glare after the procedure. You will typically
experience day and night glare for the initial three to four days
after the procedure. After a few days, you will continue to have
a small amount of night glare which generally starts to clear
at the time the second eye is treated. Typically, after six months,
you will be back to your 'pre-procedure' level of night glare.
Some patients, however, still require a thin pair of glasses or
contacts in the evening to further reduce night glare and improve
their vision. TLC doctors use only state-of-the-art laser equipment
and techniques, enabling them to significantly decrease the risk
4. HEALING HAZE -- As your eye heals, you will have blurred
vision for approximately the first week after the procedure. This
is not the healing haze, but is due to the corneal surface
cells smoothing out and the clearing of microscopic superficial
swelling. "Healing Haze", is the term for collagen protein
that develops on the surface of your eye as it remodels. When
your vision begins to improve and you are experiencing your procedure's
benefits, this is when microscopic collagen protein actually begins
to develop. Almost everyone develops 'trace' degrees of haze,
and most are not even aware of it. The probability of severe haze
that can affect your vision is as follows:
- Mild myopia <1%
- Moderate myopia 1%
- Severe myopia 2-3%
- Extreme myopia 4-5%
Severe haze is more common in patients with severe or extreme
myopia, and one of the main factors in predicting your risk is
whether you are a good healer. Among all types of procedures,
1% of patients are abnormal healers. Fortunately, the eye usually
clears with time. If haze persists, additional 'laser enhancement'
may be required.
5. UNDER CORRECTION/OVER CORRECTION - Under-correction
is more common than over-correction. Small amounts of under-correction
do not seriously affect the resulting vision, however, large amounts
may require a second enhancement procedure. Initial over-correction
is usually planned as the cornea tends to regress (i.e. 'bounce
back') somewhat toward its original shape as it heals. The eye
generally stabilizes to near predicted results
within three months, however, on rare occasions, the patient may
remain over/under-corrected. In such a situation, the patient
may have to wear a thin pair of glasses or contact lenses. After
six months, TLC doctors can usually enhance over corrected patients
as well, with newer lasers and techniques.
6. REGRESSION -- Regression is the shift back toward myopia
or astigmatism, following the excimer laser procedure. In most
cases the regression experienced is minimal. Rarely, in severe
cases of myopia, it can be significant. It is always safer to
perform a second procedure to correct regression than to significantly
overcorrect your prescription. Most patients only require a single
procedure that we fully expect will last their lifetime. About
one in ten patients will require a second 'enhancement' procedure
within the first year, which is covered in the initial procedural
7. LOSS OF SHARPNESS -- About 1% of patients experience
a small loss of visual sharpness following the excimer laser procedure.
This loss of sharpness is usually minimal (this means that you
might lose the ability to read the bottom line or two of the eye
chart). Overwhelmingly, patients actually maintain the sharpness
in their vision after the procedure. In a few instances, patients
actually gain sharpness of vision in comparison to their pre-procedure
8. FALSE EXPECTATIONS -- One of the more important difficulties
an excimer laser candidate can experience is false expectation.
Many RK or excimer advertisements you
hear on radio or see in the newspaper and television promise that
you can "throw away your glasses!". These ads can be,
and are in fact misleading. While it is true that most patients
having the excimer laser procedure will not require glasses or
contacts after the procedure, some patients will require reading
glasses or will require a thin pair of glasses for activities
such as night driving. It is best not to think of the procedure
as eliminating your glasses, but as reducing your functional
dependence upon them and improving your vision.
Finally, it is important to note that nearsighted individuals,
regardless of whether or not they choose to have the excimer laser
procedure, need to have annual dilated retinal examinations by
Risks Associated With LASIK:
The post-operative risks of the LASIK
procedure are similar in type to those involved with the PRK
procedure, as listed above, however, the statistical probability
of many of them occurring are significantly reduced with LASIK.
There are basically five main advantages to LASIK versus PRK.
- 1. The ability to correct severe and extreme cases of myopia
(up to -35.00D), and astigmatism (up to -8.00D), with greater
predictability of results and decreased probability of regression.
2. Reduced risk of healing haze, or scar tissue (0.1% vs. 2-5%
3. Reduced risk of post-operative infection (0.03% vs. 0.2% for
4. Reduced risk of post-operative pain (2% vs. 10% for PRK)
5. Faster visual recovery-- this allows both eyes to be safely
treated within days of each other.
- Due to the fact that LASIK involves the inner layers
of corneal tissue, there is a higher degree of risk during the
procedure itself than with PRK. The procedural risk that raises
the greatest level of concern among people is perforation of the
eye. There are no known cases, where an eye has actually been
perforated during the LASIK procedure.