|
Three
variables
can
be
altered
to
achieve
clear
vision.
These
are:
changing
the
light
as
it
enters
the
eye,
altering
the
front
curve
of
the
eye,
or
changing
the
length
of
the
eye.
For
centuries,
directing
light
rays
with
lenses
has
obtained
clear
vision.
Glass
or
plastic
lenses
bend
light
the
exact
amount
required
to
change
the
focal
point
to
match
the
length
of
the
eye,
producing
clear
vision.
Later,
contact
lenses
would
be
used
to
achieve
the
same
results.
Researchers
have
been
trying
for
decades
to
come
up
with
a
more
practical
solution
to
create
clear
vision.
Early
research
led
to
the
development
of
several
surgical
procedures,
including
Radial
Keratotomy
(RK)
and
Automated
Lamellar
Keratectomy
(ALK).
These
procedures
offered
some
improvements
but
were
limited
in
the
degree
of
correction
possible.
With
the
advent
of
the
excimer
laser,
more
precise
vision
correction
procedures
such
as
Photorefractive
Keratectomy
(PRK)
and
Laser
in
Situ
Keratomileusis
(LASIK)
were
developed.
Many
surgeons
believe
LASIK
to
be
a
superior
technology
for
vision
correction.
Rather
than
bend
light
before
it
enters
the
eye,
LASIK
allows
the
surgeon
to
design
a
corneal
shape
that
will
bend
incoming
light
to
correspond
with
the
length
of
the
eye.
This
technological
breakthrough
has
changed
the
way
people
think
about
vision
correction.
The
LASIK
procedure
is
performed
as
an
outpatient
procedure
with
only
a
topical
anesthetic.
The
vast
majority
of
patients
are
spectacle
or
contacts
lens
free
the
day
following
surgery!
|
In
a
myopic
eye
(commonly
referred
to
as
"nearsightedness")
light
rays
from
objects
are
focused
in
front
of
the
retina.
This
causes
images,
particularly at
a
distance,
to
be
blurred.
In
a
hyperopic
eye
(commonly
referred
to
as
"farsightedness")
light
rays
from
objects
are
focused
in
the
back
of
the
retina.
This
causes
images,
particularly
close
up,
to
be
blurred.
Astigmatism
is
a
condition
where
the
front
of
the
cornea
is
not
uniformly
curved,
but
slightly
oval
or
"football"
shaped.
As
a
result,
rays
of
light
that
enter
the
eye
are
bent
unequally
and
cause
distortion
of
the
image.
Most
people
have
some
degree
of
astigmatism.
