Vision Problems that Require Contact Lenses

Individuals with ordinary optical disorders, such as nearsightedness, farsightedness, or presbyopia, have a choice as to whether or not they want to wear contact lenses. Mostly they wear contact lenses because they look better without glasses. But there are many people who must use contact lenses, looks or no looks.

A compelling example is keratoconus, or "conical cornea," a pathological condition in which the cornea, pushed by internal pressures, tends to bulge. Unless the process is stopped, it may result in a ruptured cornea, which is further damaged by scar tissue.

Until the development of contact lenses, little or no correction was possible for keratoconus sufferers. Now, contact lenses afford almost perfect correction, and tend also to arrest development of the defect. The prophylactic effect, together with visual improvement, makes contact lenses imperative as soon as keratoconus has been diagnosed.

Cataract - a condition in which the eye's crystalline lens has lost its transparency - is another pathological defect. The cure is in variable: surgical removal of the lens - aphakia. Spectacle lenses for the correction of aphakia are commonly called "cataract lenses." Made of glass, they are very thick in the center and very heavy to wear. Plastic lenses are lighter, but even thicker at the center than glasses. In either case the wearer's appearance is hurt, and the optical results are poor. There is image distortion away from the center, and high magnification. The wearer's depth perception is distorted, so that he misjudges distances and constantly bumps into solid objects.

Contact lenses are an almost perfect solution for the aphakic patient's problems. Magnification is reduced from about 35 percent to a mere 5 percent. Objects appear almost in their true position. There is no peripheral distortion, and the lens weight is negligible.

If only one eye has developed a cataract, it is generally better not to operate, allowing the patient to get along with the vision of the normal eye. When it becomes necessary to operate on the cataract in one eye, correction problems arise. With glasses, the aphakic eye will see an image seen by the good eye, and the brain will be unable to fuse the images. The result is double vision.

Again, contact lenses offer a satisfactory solution. When a contact lens is prescribed for the aphakic eye, the image in that eye will be only slightly larger than normal. The brain will probably be able to fuse the two images.

The corrections of pathological eye disorders by contact lenses are almost miraculous, compared to past methods, but the psychological aspect of contact lens prescription is just as striking. Children, for instance, often feel that glasses are a social stigma. This is particularly true when lenses are thick enough to distort the wearer's features. In such cases, contact lenses can make the child feel accepted.

Sources:

Keratoconus: www.keratoconus.com

Cataracts and contact lenses: www.preventblindness.org/eye_problems/contacts.html -

Aphakic: www.thefind.com/beauty/info-aphakic-contact-lenses