Lasik for Myopia
Laser in-Situ Keratomileusis (LASIK) can be used
to treat low to high levels of nearsightedness (myopia) with the
goal of reducing or eliminating dependence on corrective lenses.
Nearsightedness occurs when the cornea is too curved or the eye
is too long. This causes light to focus in front of the retina,
rather than on the retina, resulting in blurry distance vision.
LASIK uses the computer-controlled precision of the Excimer laser
to treat the inner tissue of the cornea.
The procedure is done using eye drop anesthesia,
and while you may feel pressure, the technique is generally not
painful. First, an instrument known as a microkeratome makes a protective
flap in the outer layer of the cornea, at about twenty-five percent
of its depth from the surface. Next, the Excimer laser sculpts the
internal corneal tissue to the correct refractive power by flattening
the curvature of the exposed corneal tissue. The "flatter" cornea
allows light rays to focus more directly on the retina, thereby
reducing nearsightedness. The corneal flap is laid back in its original
position and allowed to dry for several minutes. Due to the cornea's
extraordinary natural bonding qualities, stitches are usually not
required.
Although the vast majority of patients see 20/20
or better postoperatively, individual results cannot be guaranteed.
Patients over the age of 40 should ask about Monovision. Monovision
can postpone the need for reading glasses. The surgery is performed
on an out-patient basis and most people return to work within one
to three days. As with any surgical procedure, side effects and
complications may occur.
What is Nearsightedness?
In the normal eye, light bends through the cornea and lens to focus
on the retina. With Nearsightedness (nearsightedness - place cursor
over image) the eye is longer (or cornea is steeper) causing light
to focus in front of the retina. The image is therefore out of focus
on the retina and vision is blurred. The Treatment
1. A thin flap of cornea is created and folded back.
2. Excimer laser is applied to reshape (ablate) the cornea.
3. The corneal flap is replaced over the treated cornea.
4.
The "flatter" cornea now bends light to become focused on the
retina.
LASIK
for Myopia Animation The Result
Before LASIK treatment, light is out of focus on the retina. After LASIK treatment (place cursor over image), the "flatter" cornea (arrow) causes light to bend in such a way as to become focused on the retina. Vision is clear.
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