| Refractive
Errors |
| Why
do some people need to wear glasses or contact lenses? |
About
50% of the general population have refractive errors,
i.e. they need to wear glasses or contact lenses to
see clearly. This situation arises because the length
of the eyeball or the shape of the cornea is abnormal,
such that an image cannot be focused on the retina
(the same as a film in a cornea). |
|
| Myopia
(Shortsightedness) |
This
is a very common condition where the eyeball length
is relatively too long, such that the image falls
short of the retina and becomes defocused. Distant
objects appear blurred. |
 |
| As
a rule, LASIK corrects myopia (shortsightedness) up
to 13.00 D |
|
| Hyperopia
(Farsightedness) |
In
this instance, the eyeball length is relatively short
and the image is focused behind the retina. The near
objects are relatively more blurred compared to the
distant objects. |
 |
| LASIK
corrects hyperopia (farsightedness) up to 6.00 D |
|
| Astigmatism |
In
this situation, the curvature of the cornea is not
spherical, but appears more egg shaped, resulting
in the inability to focus the image to a single sharp
point. Images appear distorted both from a short and
far distance. |
 |
| LASIK
corrects astigmatism up to 5.00 D |
|
| The
goal : 6/6 |
This
begins in most people around the age of 40 and is
considered as the normal aging process. This occurs
in everyone as the natural lens becomes less flexible
with age, and is unable to focus near objects. Therefore,
regardless of whether a person has refractive error
(poor eyesight) or not, most people will need to wear
reading glasses for close-up work with age.
LASIK does not correct presbyopia. In short, you must
understand that the goal of LASIK is to reduce your
dependency on the need for glasses or contact lenses
so that you can see well without the need for them.
It is important that you understand the aim of the
procedure so that you can have a realistic expectation
of the LASIK outcome.
|
|
| The
goal : 6/6 |
Traditionally,
the way to help focus images in people with poor eyesight
is with the aid of prescription glasses (spectacles)
or contact lenses.
If you can read letters 9.5mm high from 6mm away,
you have 6/6 vision. |
 |
|
| How
do I know if I am suitable for LASIK? |
- Most,
but not all people who wear glasses or contact
lenses are candidates for laser refractive surgery.
- Only
after a proper eye assessment, your doctor can
advise if you are suitable for this procedure.
- In
addition, your eye must be in good health, and
your refractive errors must be stable.
- You
must be at least 18 years old and not pregnant
at the time (to ensure stability of vision), and
not to wear contact lenses for at least for one
week prior to the surgery (as contact lens wear
may temporarily affect the power of your eye).
- Furthermore,
some patients may have too thin cornea that precludes
them from a safe LASIK procedure.
- Overall,
about 90% of patients are suitable for the LASIK
procedure.
|
