Toric Contact Lenses: Great For Astigmatism
Toric contact lenses arose out of a need that could not be addressed by regular contact lenses. For many years after they were introduced, contact lenses could easily fix nearsightedness and farsightedness but could do nothing for astigmatism. Through careful crafting of contact lenses, it became possible to change where light rays focused on the retina and return the eye to 20/20 vision. Astigmatism is different and posed a special problem that was not solvable by the technology of the that time, forcing people with astigmatism to continue wearing glasses. Toric contact lenses ultimately solved that problem.
Vision problems usually happen because the eye incorrectly focuses light rays in relation to the retina. Farsightedness causes light rays to focus behind the retina, while nearsightedness causes light rays to focus in front of it.
Astigmatism is a different problem. It’s a condition where the cornea, lens or eyeball as a whole is oddly shaped compared to a normal eye. The physical distortion is usually small, but even small differences in the eye produce a large effect on vision. Light rays scatter in many different directions–not just ahead of, behind, or on the retina. The unfortunate result is blurred vision.
The scattering of light caused by astigmatism made it more difficult to produce contact lenses to fix the problem. Toric contact lenses solve the problem by combining different geometric shapes so as to focus light correctly. Ordinary contact lenses are shaped like a half sphere, but toric lenses combine a spherical surface with a donut shaped (toroidal) one. This special shape prevents light from scattering.
Despite their different shape, toric contact lenses are made of all the same materials as other contact lenses. They can be soft, hard, or rigid gas permeable (RGP). Unlike other contact lenses, they can’t be allowed to rotate around the eye–the toric lens shape must remain firmly in place to prevent the scattering of light. That could mean, for example, that they are weighed towards the bottom so as to keep that side of the lens on the bottom part of the eye.
Toric contact lenses can also be designed to address more than one vision problem at the same time, such as astigmatism and farsightedness. This flexibility makes toric contact lenses more difficult to manufacture correctly, and eye exams and fitting can be more complicated.
As a result of their special qualities, toric lenses are sometimes more expensive. People with a mild astigmatism might avoid the extra expense by just using ordinary contact lenses. The cornea will to some extent conform to the shape of the lens and minimize the scattering of light. In fact, toric lenses may not be necessary at all for mild astigmatism. Only your eye doctor can say for certain after administering an exam.
For people end up needing toric contact lenses, there are many options available. You can purchase single or multifocal lenses. Toric lenses are also available in the same types as regular lenses–disposable, single day wear, weekly wear, monthly wear, and even extended wear.
If you suffer from astigmatism, then there are sure to be great toric contact lenses to fit your budget and lifestyle.
Stop by David Long’s toric contact lensessite, where you can find every type of toric lenses for your needs.
