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Astigmatism and Toric Lenses – The Condition And The Solution

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Astigmatism and Toric Lenses – The Condition And The Solution Powered By Docstoc
					Astigmatism is quite a common condition caused by irregularities in the
cornea or lens of the eye, and distorts the image on the retina. Those
having a slight blurred vision are not even aware that they have
astigmatism. In the case of more severe astigmatism, everything is blurry
at a distance, and it becomes impossible to ignore the condition. People
who suffer from astigmatism can have their vision improved by the usage
of toric lenses.

Usually, astigmatism is a hereditary condition, where the shape of the
eye is irregular. The normal spherical shape of the cornea, or the lens,
of the eye is more oblong - football ball like. Astigmatism may accompany
Myopia (nearsightedness) or Hyperopia (farsightedness). Astigmatism can
usually be corrected with toric contact lenses among other methods, such
as glasses and refractive surgery.

Types Of Astigmatism

There are basically two variations of astigmatism – regular astigmatism
and irregular astigmatism.

Regular astigmatism is usually easier to correct. In it, the meridians in
which the two different curves are, are located 180 degrees apart. In the
case of irregular astigmatism, which is more difficult to correct, the
two meridians may be more, or less, than 180 degrees apart, or there may
be more than two meridians. Correcting this is quite complicated and
depends on the extent of irregularity, and the cause behind it.



Toric lenses can easily correct regular astigmatism, whereas irregular
astigmatism, being more complicated and difficult to correct, requires
custom made contact lenses. Astigmatism, whether slight or severe, should
not be ignored, as it not only gives you a blurred vision, it also gives
you headaches and eyestrain.

Children too develop astigmatism and are either generally not aware, or
do not complain. Nevertheless, it makes their life quite difficult. It is
best that you have your child's eyes tested every year, and if diagnosed
with astigmatism, can have this condition corrected with toric contact
lenses.

Toric Lenses For Astigmatism

The earlier   belief that people with astigmatism could not wear contact
lenses, and   only Rigid Gas Permeable (RGP) contact lenses could correct
astigmatism   is no longer true. Soft contact lenses that can correct
astigmatism   are called toric contact lenses, and they can do an equally
good job of   correcting your, and your child's, astigmatic vision.



They have a special inbuilt correction that also has correction for
either nearsightedness, or farsightedness, depending on your condition.
In the past soft toric contact lenses were not available in disposable,
frequent replacement, multi-focal, or colored varieties. Today, you have
many options available to correct your astigmatism with toric contact
lenses, unless you have an especially complicated prescription.

Soft toric contact lenses are made from the same materials regular
contact lenses, which are also known as spherical contact lenses, are
made from. To take care of astigmatism, and either myopia or hyperopia,
toric lenses are created to have two different powers in them with
curvatures at different angles.

The normal 'spherical' contact lenses have the same power all around, and
so it does not matter if the lens rotates in the eye. In the case of
toric contact lenses, due to the two different powers, there is a need to
keep the lens from rotating, to maintain the best visual acuity. For
this, they are 'ballasted' by making them heavier at the bottom. This
mechanism keeps the lens relatively stable, providing you with crisp
vision, when you look around or blink.

The fitting of the soft toric contact lenses will take more time and
expertise of your optometrist than for the normal regular contacts. Some
eye care practitioners may fit you with high powered spherical soft
lenses to correct your mild astigmatism. The results will vary from
person to person, and by a trial and error method. It is best to opt for
toric contact lenses, even though the cost of fitting, and the cost of
the lenses themselves, will be more than the spherical lenses.

Types Of Toric Contact Lenses

When looking for toric contact lenses, you have a choice of color and
disposable lenses.

Toric contact lenses are available in many colors that change or enhance
your natural eye color. Most colored toric contact lenses are non-
disposable conventional contacts, and only some colors are available as
disposables.

The four types of colored toric contact lenses are visibility tints,
enhancement tints, opaque color tints and light-filtering tints.

Visibility Tints – These are usually with a light blue or green tint.
These tints are added to a lens, just to help you see it better if you
drop it, or during insertion and removal. The very light tint does not
affect your natural eye color.

Enhancement Tints – These are   translucent but solid tints that are a bit
darker than visibility tints.   They do affect eye color, as they are meant
to enhance the existing color   of your eyes, as implied by the name. They
intensify your eye color, and   produce the best results for people who
have light colored eyes.

Opaque Color Tints - The deeper opaque tints dramatically change your eye
color. They best change your eye color especially if you have dark eyes.
The colors include hazel, green, blue, violet, amethyst and gray.
Light Filtering Tints – The latest in color toric contact lenses are the
ones with light filtering tints. Specially designed for sports use, the
light filtering tints enhance certain colors, by muting other colors.
They enhance the vision of sportsmen by making the ball stand out against
the background, and allow them to see the target more easily.

Disposable lenses were designed to be worn for a specific period and then
to be disposed of. They are more hygienic than traditional lenses as
substances that are found naturally in your tears, like protein, calcium,
and lipids, can build up on your lenses, causing discomfort. The
alternate to disposable lenses is to clean your conventional toric lenses
regularly.

If you are suffering from astigmatism, it is best you visit your
optometrist for a fitting of toric contact lenses – the best option
available today.

Michael Wright is a virtual authority on contact lenses.   He also writes
articles about astigmatism and colored contacts.

				
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