Uses
Many people are inflicted with a sight disability known as astigmatism, a condition in which the cornea of the eye is curved irregularly, leading to vision reduction. One of the best solutions to this problem is to obtain special contact lenses known as toric lenses, which have the same soft and comfortable structure that normal contact lenses have, but offer an extra angled lens in order to better correct the poor eyesight that may be associated with an astigmatism or other sight irregularities.
Structure
While these contacts may look and feel the same, they incorporate not one, but two curvatures with differentiated angularities to better compensate for astigmatism. They can also be used to treat people suffering from irregular eyesight due to hyperopia (farsightedness) or myopia (nearsightedness). They also have the ability to stabilize a person's variegated vision when the person is in motion, thus reducing blur and creating a more sharpened view of objects due to a reduction in the time needed to focus when switching from one object to another.
Vision Correction
This double-powered lens system works through the use of something called a ballast system. A ballast system consists of two lenses in which the bottom lens is thicker in order to better maintain the entire contact's position in the eye. Poor eyesight is caused in part by very minute differences in the eye, which in turn can create a large effect in terms of poor eyesight. In astigmatism, the irregularly-curved corneas scatter incoming light rays in directions that can cause objects to appear blurry. The multiple curvatures and shapes in toric lenses allow for a more effective and precise redirection of those misdirected light rays. They are able to do this through the addition of a toroidal surface to the normally spherical surface of contact lenses. A toroid is a cylindrical shape that circles around to reconnect with itself. This allows light to be redirected in multiple directions, thus providing a solution for people with multiple points of sight disability.
