A regular contact lens has two surfaces – an inner and an outer – which are manufactured to be like portions of a sphere. This allows them to sit on the surface of an eye comfortably, since the eye itself is spherical.
However, there are certain eye conditions which cause the eye to have an abnormal, non-spherical shape. The most common of these conditions is astigmatism. This is where the eye is an irregular shape, often like a stretched sphere, or a cylinder.
People who suffer from astigmatism, and similar conditions, cannot wear normal contact lenses because they do not sit properly on the eye. This can lead to blurry vision, irritation, dry eyes, and even to contact lenses falling out of the eye because they are not seated properly.
Toric contact lenses are designed specifically for people with conditions such as these. Rather than both surfaces being spherical in shape, one of both are more cylindrical. This allows the lens to flex more, and mold itself to the shape of the wearer’s eye.
Some people may only have astigmatism in one eye, rather than both. In these cases it is common for them to wear one normal lens and one toric one. Of course it is important to ensure the correct contact is being worn in the correct eye.
Further, some toric lenses have a specific ‘top’ and ‘bottom’, which means it cannot be worn any way round like with a traditional lens. This is normally marked with very subtle lettering near the edge of the lens, where it won’t be seen once in place.
Toric contacts are made from the same materials as normal lenses. However, because of their specialist design, they are more expensive, so generally are meant for longer term use, rather than being disposable.
If you suffer from an eye condition which means you can’t wear regular lenses, then a toric lens may be an excellent option for you.