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Normal vision (Emmetropia)
 For
you to see clearly, light rays must be focused by the cornea
and the lens to fall precisely on the retina. Your vision
is clear if the cornea and lens continue to focus near and
far objects precisely on the retina. The lens is located inside
the eye behind the iris (the coloured part of the eye). The
retina is the inner layer on the back of the eye that senses
light. It converts the light rays into impulses that are sent
through the optic nerve to the brain, which interprets them
as images.
Refractive errors
Refractive errors have in common that there is a mismatch
between the focusing ability of the cornea and lens on one
hand and the length of the eyeball on the other. Refractive
errors are classified as MYOPIA
or short-sightedness, HYPEROPIA
or long-sightedness and ASTIGMATISM.
These disorders may be developmental and is usually so, or
it can be acquired as a result of disease or injury. These
refractive problems are solved by helping the eye to focus
light precisely on the retina, using glasses, contact lenses
or refractive surgery.
Refractive eye surgery
Many people rely on glasses and contact lenses to correct
their vision, but some find these methods inconvenient, uncomfortable
or unattractive. Spectacles and contact lenses are not always
ideal for certain occupations and sporting activities. For
those patients who are unhappy with their spectacles or glasses,
a permanent alternative may well be economically preferable
to the regular optical aid replacement many of these people
need. Refractive eye surgery includes several surgical and
laser techniques designed to improve problems in focusing
the eyes. It has developed rapidly in recent years.
This website is not intended to be comprehensive, but to
give an outline view of what is possible together with some
background information on ocular physiology and optics. It
is to be noted that refractive surgery is only contemplated
on eyes and in patients where some specifc eye problems have
been excluded.
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