LASIK
had
its
origins
about
thirty
years
ago
and
was
originally
developed
to
treat
patients
who
had
very
poor
vision
due
to
corneal
disease.
It
has
now
evolved
into
a successful
technique
for
correcting
refractive
errors.
The
current
procedure,
done
on
an
outpatient
basis,
involves
both
the
use
of
conventional
and
laser
surgery
to
correct
nearsightedness,
farsightedness
and
astigmatism.
LASIK
can
correct
a much
higher
degree
of
nearsightedness,
with
or
without
astigmatism,
than
any
other
refractive
procedure,
with
excellent
results
(95%
of
patients
achieve
20/40
vision
or
better). In
performing
LASIK,
eye
drop
anesthetic
is
used
to
numb
the
eye.
The
surgeon
then
uses
a special
instrument
to
cut
into
and
behind
a layer
of
the
cornea.
A portion
of
the
cornea
is
peeled
back
to
create
a flap
and
expose
the
inner
portions
of
corneal
tissue.
The
eye
is
then
positioned
under
the
excimer
laser,
which
has
been
computer
programmed
to
remove
microscopic
amounts
of
the
internal
corneal
tissue.
Removal
of
the
tissue
changes
the
curvature
of
the
cornea.
If
the
patient
is
nearsighted,
tissue
closer
to
the
central
part
of
the
cornea
is
removed
to
decrease
the
curvature
and
effectively
flatten
the
cornea.
If
a patient
is
farsighted,
tissue
in
the
peripheral
part
of
the
cornea
is
removed
to
increase
the
curvature
of
the
cornea.
To
correct
for
astigmatism,
selected
tissue
at
certain
angles
is
removed
to
ensure
that
the
cornea
curves
equally
in
all
directions.
After
the
laser
has
been
used,
the
flap
is
returned
to
its
original
position.
The
corneal
tissue
has
extraordinary
natural
bonding
qualities
that
allow
effective
healing
without
the
use
of
stitches. Since
only
local
anesthetic
is
used,
patients
remain
awake
during
the
procedure.
The
entire
procedure
takes
only
a few
minutes.
Improved
vision
is
often
possible
on
the
day
following
the
surgery.
After
surgery,
eye
drops
may
be
prescribed,
and
it
may
be
necessary
to
wear
a protective
eye
shield
at
night.
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