The Multiple Uses of Toric Contact Lenses

August 23, 2009 by  
Filed under Contact Lenses

Contact lenses have been around for quite some time, but for pretty long everyone could not benefit from it. A contact lens was effective as far as the problem was only farsightedness or nearsightedness, which required only a simple bending of the light rays for the vision to get corrected. But it was not possible to use contact lenses for astigmatism. The problem was finally solved by the arrival of toric lenses on the scene.

Myopia, or nearsightedness, is the result of the image forming in front of the retina while hyperopia, or farsightedness, is the result of the image forming behind the retina. Astigmatism is neither and is the result of the eyeball changing shape. Because of the change in shape, light rays go here and there not forming a clear picture and thereby the vision becomes blurred.

Because of the different directions in which light rays get scattered in the case of astigmatism, it is difficult to make contact lenses for astigmatism. In fact, making even ordinary glasses was a little difficult in the case of astigmatism. Ordinary eye contacts or eye glasses are shaped like the part of a sphere. Astigmatism required the lens to have different shapes and that was not easy.

The structure of toric lenses solves this problem to a large extent as it can combine shapes. Toric lenses are a combination of a toroidal surface and a spherical surface. A toroidal surface is the surface that is created by a torus, or the shape of a revolving circle like a doughnut or a tube that is kept in a circular form. Because of this double surface, toris lens solved the problem of making contact lenses for astigmatism.

Though the shape is different, the material of a toric lens is the same as that of other contact lenses. It may be hard, soft, or RGP. But because of the powers of its shape, a contact lens made of toric lens can be designed to contain lenses of varying powers and can be used to correct two vision problems like hyperopia and astigmatism together. So the manufacturing process of a toric lens and its fitting process are very exacting jobs.

Because of the delicate and demanding work involved in fashioning toric lenses, these contact lenses are quite expensive. Even the doctor’s visits related to it are expensive. For a mild case of astigmatism, regular contact lenses would suffice to solve the problem. But for certain cases of astigmatism, or other eye problems, the doctor may suggest that the use of toric lens is mandatory.

There is a wide range of choices available for toric lenses. Toric lenses are used as contact lenses for astigmatism, or bifocal contact lenses or multifocals. They come as disposable contact lenses or can be extended wear contact lenses that may last 2 days, a week, or even a month. Toric lenses are also available as colored contact lenses. Among the colored ones there are further choices like those with limited visibility tints, or those with color tints that can darken eye color, or those that can change eye color completely.

If the doctor prescribes a toric contact lens for you, there is definitely no shortage of patterns or styles in this type contact lens.