What should I know about laser surgery?What should I know about laser surgery?
In 1982 scientists discovered that by mixing different gases together a specific laser of 193 nanometers wavelength could remove molecules of tissue without applying damage to surrounding structures. Damage to surrounding tissues was avoidable with this specific wavelength of laser light because it was able to remove tissue without using heat. There are many different types of lasers, this particular laser is called the "excimer laser." This laser is able to vaporize tissue by breaking molecular bonds a few layers at a time. As this laser is able to remove tissue less than 1/1,000 of a millimeter at a time, it's value as a surgical tool was quickly appreciated.
There are three common focusing problems. These are nearsightedness, farsightedness and astigmatism.
Nearsightedness usually results from an eyeball that has
developed an overall length from the front to the back of the eye to be
longer than normal. The cornea, which is the outermost window of the
eye, along with the lens of the eye focuses light from our world upon
the retina. The retina in turn changes these rays of light into
electrical impulses that are then sent through the optic nerve to the
visual center in the brain. If the cornea is too steep or pointy, for
example, as rays of light enter the eye they are put into focus in
front of the retina instead of upon it as is seen in nearsightedness.
People who are newsighted see more clearly closer to them than far
away.
Farsightedness usually results from an eyeball that has developed to be shorter in length than normal. Sometimes a flattened cornea can be the cause of farsightedness as well. Farsighted people see distant objects more clearly, however, it is also possible that objects at all distances can be blurred.
Astigmatism results from an inability of the eye to clearly
focus at any distance. This is usually due to an irregularly curved
cornea. Instead of the cornea being uniformly rounded much like a steel
ball, there are areas of the cornea that are steep and other areas of
the cornea that are flattened. This misshapen cornea causes rays of
light entering the eye to be put into focus at several different points
upon the retina causing a distortion in vision. Laser surgery reshapes
and smoothes the cornea to enable rays of light from the world to be
put into a single point of focus upon the retina.
Presbyopia is another form of vision which refers to an ageing
eye. Presbyopia is most commonly seen in people who are 40 years old or
older. It causes difficulty with reading material within arm's length.
Presbyopia occurs with or without laser surgery. Laser surgery at the
present time is unable to correct presbyopia.
Does laser surgery hurt?
There are actually several different techniques used to perform the
procedure. Generally speaking, discomfort associated with laser surgery
is mild. Everyone, however, has a different tolerance to pain. Be
careful concerning claims that laser surgery does not hurt. Like in
most things, words such as "always" or "never" are usually not
completely accurate.
Can you name some of the most common laser procedures?
At the present time the two most common laser procedures performed are Lasik and PRK.
Lasik involves the fabrication of a thin corneal flap, then the
remaining cornea is resculptured, the flap put back in place, and the
eye enabled more normal focus.
PRK or Photorefractive Keratectomy is a less invasive technique which does not involve a flap. The cornea is sculptured and reshaped, enabling clearer vision.
What Might I feel during a laser procedure?
Normally oral medicines, such as Valium for example, are given to
relieve a person's anxiety. Only eye drops are used to numb the eye.
There are no needles involved. You might hear the surgeon and staff
speaking to each other during the procedure, but the procedure itself
lasts only a few minutes. Most of the time that a patient spends in the
laser room has to do with preparing the patient for the procedure.
Laser surgery is performed with the patient reclined for the few
minutes that it takes to perform the procedure.
What kind of vision might I expect after laser surgery?
Most patients will see between 20/20 and 20/40 after laser surgery.
20/40 is the level of vision that a person would need to have in order
to see to drive without glasses. You might require more than a single
treatment to enable clear vision. This is especially true for people
with eyeglass prescriptions that are very large before the procedure.
Can anyone have laser surgery?
Most people these days are candidates for laser surgery. The range of
treatments that are able to be corrected has expanded. It is helpful
for the screening process for one to bring either eye glasses or an eye
glasses prescription to determine if the person is a suitable
candidate. It is not true that everyone is a candidate.
Can both eyes be treated at the same time?
Yes. The majority of patients who undergo laser surgery choose bilateral simultaneous procedures.
Can I still wear contact lenses after under going laser surger?
Usually yes. However, a specialty contact lens might rarely be required
with the new shape of the cornea. Depending on the severity of the
preoperative eye glass prescription.
If I am treated, and my vision is still somewhat blurry after the procedure, is it possible to be treated again?
Yes. Retreatments are ofter called "enhancements". There can be
situations which would make it more prudent not to retreat. However,
enhancements to improve vision will occur in any laser surgery clinic.
Usually one would wait from 3 to 6 months for enhancements or
fine-tuning of vision.
Does it make a difference which laser clinic performs my procedure?
Absolutely! Equipment, technique, and experience can play very important roles in obtaining the very best outcomes.
Are there any potential adverse side effects?
Surprisingly, there appears to be minimal risks associated with laser
vision correction. Complication rates very from clinic to clinic and
are in the range of 1 to 5% of patients. Some potential adverse side
effects include glare, light sensitivity, overcorrection,
under-correction, infection, delayed wound healing.
I have heard a lot about laser surgery, how do I know if this would be something for me?
Candidates for laser surgery:
•I feel frustrated or handicapped by my dependance upon eye glasses or contact lenses.
•I am unable to wear my contact lenses happily.
•I prefer to routinely sleep in my contact lenses.
•I have had ulcers or infections with contact lens wear.
•I would enjoy more freedom to participate in sports activities without being encumbered by glasses or contact lenses.
•I worry about being incapacitated should I lose my eye glasses or contact lenses in a crises situation.
•I would be pleased if my vision were greatly improved even if my vision wasn't made completely perfect.
•My vision seems distorted in eye glasses.
•I might have better career opportunities if I were without glasses or contacts.
•My eyes are too dry for contact lenses.
•I would be content to wear "specialty glasses" for things such as
driving or going to the cinema as long as my vision were to be much
improved enabling good vision for most things.
•I don't like glasses and cannot put anything into my eyes.
Poor Candidates for Laser Surgery.
•I have never had any concerns about wearing glasses or contact lenses.
•My spouse suggested that I consider laser surgery, (never my idea).
•I would be quite disappointed if my vision were not at least 20/20
after laser surgery and I would consider the exerience a failure.
•I would be very disappointed if I found out after laser surgery that I
could not wear contact lenses as easily as I could before the
procedure.
•I want laser surgery because many of my friends have had it and seem to be very happy with it.
•My perscription changes frequently.
LASIK or Lasik (laser-assisted in situ keratomileusis) is a type of refractive laser eye surgery performed by ophthalmologists for correcting myopia, hyperopia, and astigmatism. The procedure is generally preferred to photorefractive keratectomy, PRK, (also called ASA, Advanced Surface Ablation) because it requires less time for the patient's recovery, and the patient feels less pain overall. However, there are instances where a PRK/ASA procedure is medically justified as being a better alternative to LASIK.[citation needed]
Many patients choose LASIK as an alternative to wearing corrective eyeglasses or contact lenses.
レーシック (LASIK: Laser in Situ Keratomileusis ) とは角膜屈折矯正手術の一種で、目の表面の角膜にエキシマレーザーを照射し、角膜の曲率を変えることにより視力を矯正する手術である。一般的に近視の場合は、眼鏡やコンタクトレンズ等の道具を使用することにより視力を補正するが、角膜を矯正手術することにより限りなく正視の状態に近づける手術である。裸眼のまま、一定の視力が確保される。1990年代にアメリカを中心にその手術方法が認知されるようになった。wiki