Overview of Refractive and Laser
Eye Surgery
Introduction
Vision repair surgery, also called refractive and laser eye
surgery, is any surgical procedure used to correct vision
problems. In recent years, tremendous advancements have been
made in this field. After refractive and laser eye surgery, many
patients report seeing better than they had at any other time in
their lives.
All refractive and laser eye surgeries work by reshaping the
cornea, or clear front part of the eye, so that light traveling
through it is properly focused onto the retina located in the
back of the eye. There are a number of different types of
refractive or laser eye surgeries used to reshape the cornea,
including:
- LASIK: Short for laser in-situ keratomileusis,
this laser eye surgery is used to correct vision in people
who are nearsighted , farsighted , and/or have astigmatism . During
LASIK laser eye surgery, vision is corrected by reshaping underlying corneal
tissue so that it can properly focus light into the eye and onto the retina.
LASIK laser eye surgery differs from others in that a flap is made in the
outer layer of the cornea so that the underlying tissue can be accessed.
- PRK: Short for photorefractive keratectomy, this
laser eye surgery is used to correct mild to moderate
nearsightedness, farsightedness,
and/or astigmatism. During PRK laser eye surgery, an eye surgeon uses a laser
to reshape the cornea. This laser, which delivers a cool pulsing beam of
ultraviolet light, is used on the surface of the cornea, not underneath the
cornea, like in LASIK laser eye surgery. Therefore, no cutting is required.
- LASEK: Short for laser
epithelial keratomileusis, this is a newer form of laser eye surgery that
combines many of the benefits of LASIK and PRK. However, unlike LASIK and PRK
laser eye surgeries, there is no cutting or scraping of the eye. Instead an
epitheal flap is created using a 20% alcohol solution. LASEK laser eye surgery
is used to treat nearsightedness, farsightedness, and astigmatism.
- ALK: Short for automated
lamellar keratoplasty, this eye surgery is used to correct vision in people
with severe nearsightedness and slight degrees of farsightedness. As in LASIK
laser eye surgery, a flap is created in the cornea so that the doctor can
reach the underlying tissue. However, during this procedure, a laser is not
used to correct vision. Instead, another incision is made on the sub layer of
the cornea to reshape the cornea.
- LTK: Short for laser
thermokeratoplasty, this is a new laser eye surgery is used to treat
farsightedness and astigmatism. During LTK laser eye surgery, a laser beam
uses heat to shrink and reshape the cornea. Vision is corrected in a matter of
seconds, without any cutting or removal of tissue.
- AK: Short for astigmatic
keratotomy, this is not laser eye surgery, but a surgical procedure used to
correct astigmatism. The cornea of people who have astigmatism is shaped like
a football. AK eye surgery corrects astigmatism by making one or two incisions
at the steepest part of the cornea. These incisions cause the cornea to relax
and take a more rounded shape. This eye surgery may be used alone, or in
combination with other laser eye surgeries such as PRK, LASIK, or RK.
- RK: Short for radial keratotomy, this eye surgery
was once one of the most frequently used procedures to
correct nearsightedness. However, since the development of
more effective laser eye surgeries, such as LASIK and PRK,
RK is rarely used today.
Are Refractive and Laser Eye Surgeries Safe and Effective?
While the results of laser eye surgeries have been promising,
there are possible side effects. It is important to keep these
side effects in mind when considering refractive or laser eye
surgery.
- Infection and delayed healing. Infection resulting from PRK occurs in one-tenth of one percent
of patients. For LASIK laser eye surgery, this number is even smaller. If an
infection does result from refractive or laser eye surgery, it generally means
added discomfort and a longer healing process.
- Undercorrection or overcorrection. It is difficult to accurately predict the success of
refractive or laser eye surgery until the eye has healed properly. Patients
may still need to wear corrective lenses even after laser eye surgery. Often
surgeries resulting in undercorrections can be adjusted with a second laser
eye surgery.
- Worse vision. Occasionally
the vision through corrective lenses is actually worse after refractive or
laser eye surgery than it was before. This may be a result of irregular tissue
removal or excess corneal haze.
- Excess corneal haze.
Corneal haze occurs as a part of the natural healing process after some
refractive or laser eye surgeries, including PRK. It usually has no effect on
the final outcome of vision after laser eye surgery and can only be seen
through an eye examination. Occasionally, however, this haze may affect a
patient's vision. A second refractive or laser eye surgery may be needed to
correct it. The risk of corneal haze is much less with LASIK laser eye surgery
than it is with PRK.
- Regression. Sometimes the
effects of refractive or laser eye surgery gradually disappear over a period
of several months. When this happens a second surgery is often recommended to
achieve permanent results.
- Halo effect. The halo
effect is an optical effect that occurs in dim light. As the pupil enlarges,
the untreated area on the outside of the cornea produces a second image.
Occurring sometimes in patients having LASIK laser eye surgery or PRK, this
can affect and interfere with night driving, especially in patients who have
big pupils in dark conditions.
- Flap damage or loss. This is a risk factor with
LASIK laser eye surgery only. Instead of creating a hinged
flap on the central cornea that can be closed, the entire
flap may detach, risking permanent damage to the cornea.
Refractive and laser eye surgeries require healthy eyes that are
free from retinal problems, corneal
scars, and any eye disease.
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