Correcting Astigmatism
with Contact Lenses
Suffering from Astigmatism?
Astigmatism for a long time was an eye problem which could
not be fully corrected with contact lenses. Mild astigmatism
could be sufficiently improved with soft contact lenses, but
there weren't options for the more serious cases.
The eye problem itself usually results from a misshaped cornea,
instead of being spherical like a ball, the cornea in people
with astigmatism is oblong, which is shaped more like a football.
And due to this shape, light rays can't refract properly against
the retina. So, instead of focusing the rays on one spot,
the odd shape causes light to refract in multiple locations
on the retina, causing the blurred vision, despite of distance,
which is symptomatic of astigmatism.
Toric Contact Lenses
The development of toric contact lenses has been a great
help for people with astigmatism. Toric contact lenses look
the same as soft or rigid gas permeable contact lenses, but
in fact they are very different. The lenses include of a number
of different curvatures in various meridians or sections on
the lens. Since astigmatism is a problem which involves unbalanced
meridian sections (due to the odd shape of the cornea) bringing
the meridian sections back into balance is what helps produce
clear vision.
Since the positioning of the various curvatures is major
key to improving vision, toric soft contact lenses cannot
rotate and they must be held in a certain position in order
to be effective. This can be done in a few ways. One way is
to add weight to the bottom of the lens by building up or
thickening that section. Another way is to make the top part
of the lens lighter, by thinning this section.
Rigid Gas Permeable Lenses
Another way to correct astigmatism with contact lenses is
with the use rigid gas permeable lenses. These lenses are
not as delicate as soft lenses and that enables them to hold
onto their shapes, even after blinking. Regular gas permeable
lenses work great at correcting mild to moderate astigmatism,
but in cases where the astigmatism is serious, you usually
need to purchase gas permeable toric contact lenses. Toric
lenses are custom shaped so that the inside of the lens more
closely matches the shape of the astigmatism. With this customized
fit, toric lenses remain in position and rotation isn't an
issue.
Due to the fact that toric contact lenses involve customization,
you usually have to pay more for this type of contact lens.
You might even find that your eye doctor charges more when
fitting you for toric lenses with the extra work involved
in measuring each eye properly.
If you work with an eye doctor you trust, then you will most
likely be given to try regular contact lenses to treat your
astigmatism. Usually, mild and moderate astigmatism can be
adequately corrected with standard lenses. Only when the astigmatism
becomes severe, then you will have to be prescribed toric
style contact lenses. When this happens, you'll find that
toric lenses are available as daily wear, extended wear, silicone
hydrogel and disposable brands. Good thing is, they even come
in an assortment of eye color options!
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