Nearsightedness

The Science Behind Your Eyes

Nearsightedness: The Cornea

Orthokeratology is the science of modifying the curvature/shape of the cornea to change how light is focused on the retina (back part of the eye). The cornea is a clear, dome-shaped structure that overlies the colored iris. Corneal tissue is clear, and closely resembles wet skin, and like skin tissue, it is very pliable. The cornea functions as a protective layer that separates the eyes’ contents from the environment and its unique structural curvature are able to bend the light rays towards the back of the eye. It is responsible for most of the eyes’ corrective power and contributes to various conditions such as nearsightedness (myopia), farsightedness (hyperopia) and astigmatism.

The Science Behind Myopia (Nearsightedness)

Myopia control is used to slow or stop the increase in axial length of the eye (how long the eyeball is). Blurry vision will cause the eye to extend in axial length, and as the axial length increases, the level of myopia will get larger. Children and adults can be treated with Ortho-K because the principle of flattening the cornea is effective for both types of patients. Myopia control is used to slow/stop the increase in axial length of the eye that occurs in growing children who suffer from the effects of increased nearsightedness each year (patients whose spectacle prescription continues to increase in power every year). Myopia control therapy can result in a lower prescription, so the patient won’t have to wear thick lenses, otherwise required, by the time they become a teenager.

One of the most exciting areas of research in Orthokeratology and Corneal Re-shaping (CR) has to do with the control of myopic progression. At the present time, it appears that CR can essentially stop the progression of myopia in a young, emerging myope (someone who experiences nearsightedness). The use of CR lenses on a young myope is the best alternative for preventing the progression of myopia. Research indicates that it is better than Rigid Gas Permeable lenses (RGPs), bifocal therapy, progressive lens therapy, atropinizing drugs, vision therapy and under-correcting the myopia.