Astigmatism is characterized by an irregularly-shaped cornea which causes light images to focus on two separate points in the eye, creating a distorted image. Symptoms range from visual discomfort in mild cases, to severe blurring and distortion similar to a reflection in a funhouse mirror.
Contact lenses designed to correct this condition are fitted to each individual. The misshapen cornea is measured and special toric lenses are used to direct light rays to one spot on the retina. There are more than 60 thousand different toric prescriptions available, offering Canadians an alternative to eyeglasses.
Due to their firm design, Rigid Gas Permeable (RGP) lenses offer a high degree of corrective ability for this condition. In many cases, RGP lenses do not need a complicated toric design, because they are able to compensate for the irregularly-shaped cornea.
Presbyopia develops as the eye's lens grows older and begins to lose the elasticity needed to switch focus between viewing near and far objects. Also know as 'aging eye,' this condition actually starts at about age 10, though most people do not begin to experience its effects until their forties. As the eye's lens continues to lose its elasticity, the eye takes longer to adjust between objects such as the road and the speedometer.
Half-glasses or bifocals used to be the only answer for people with presbyopia. Today, there are a number of contact lenses that can correct this condition. These lenses include multifocal contacts and specialized fitting techniques such as monovision.
