EYE FUNCTION CONDITION FAQ
1. Myopia (short-sightedness)
2. Hypermetropia (long-sightedness)
3. Astigmatism (uneven bending of light rays)
4. Presbyopia
5. Monovision
1. Myopia (short-sightedness)
Myopia or short-sightedness is a condition in which the eye
can see close objects but has difficulty bringing distant objects
into focus.
Myopia is often detected in childhood and typically the condition
progresses during the teenage years but levels off in early
adulthood. As a result there may be a need for new glasses every
six to twelve months during this period of progression. There
is usually very little change in this condition after the early
to mid twenties.
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2. Hypermetropia (long-sightedness)
Hypermetropia is the opposite of myopia. Hypermetropia is
when the distance between the cornea, at the front of the eye,
and the retina, at the back of the eye, is shorter than normal.
Unlike myopia, long-sighted eyes tend to require glasses correction
at an older age. One of the earliest signs of hypermetropia
is the premature requirement for reading glasses.
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3. Astigmatism (uneven bending of light
rays)
Figure 1A. Corneal topography – Astigmatism. The bow-tie shape
indicates astigmatism is present.
For normal, undistorted vision, the cornea should be smooth
and equally curved in all directions. In an astigmatic eye,
the cornea curves more in one direction than the other so that
the surface is more like the shape of a football or rugby ball
rather than a soccer ball.
Astigmatism distorts or blurs vision for objects at any distance.
It is usually evident from an early age and will require some
form of vision correction. Low level astigmatism is very common,
and may not be bothersome. Astigmatism commonly occurs together
with myopia or hypermetropia.
Figure 2A. 3D image of a corneal topography.
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4. Presbyopia
Presbyopia is the effect of the ageing process on your vision.
As you age it is not uncommon to experience a gradual difficulty
in focusing your eyes for reading or close work. This is a condition
that can be easily corrected with reading glasses, but it is
normal to require a gradual increase in their strength over
the years. It will not bother most people until they are in
their mid 40s, an age when the lens gradually starts to lose
some of its flexibility.
Bifocal or multifocal lenses may need to be prescribed for
people with presbyopia if they also suffer myopia, astigmatism
or hypermetropia.
After the laser vision correction procedure you will typically
be normally sighted and you will be just like every other normal-sighted
person in that, when you reach your mid-forties reading glasses
will usually be required. The excimer laser has no effect on
your eye's focusing muscles or the lens. As such, the excimer
laser cannot directly help patients who are solely experiencing
the effects of presbyopia. However, Monovision can be used to
help overcome some of the limitations arising from presbyopia.
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5. Monovision
Monovision is a treatment for presbyopia where one eye may
be corrected by laser for reading and the other eye for distance
vision, so in effect you use one eye for near sight and the
other for distance.
This treatment is not suitable for everyone but we can discuss
the details with you and discuss your suitability. Your regular
eye care practitioner can provide a contact lens for a trial
of Monovision to see if this option suits your lifestyle. A
choice for laser vision correction is a lifestyle decision,
whether it is for practical, professional, sporting or leisure
purposes.
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