Orthokeratology (sometimes called OrthoK or corneal reshaping lenses), is a procedure where your contact lens practitioner uses specially designed rigid gas-permeable (RGP) contact lenses to alter the shape of your cornea to temporarily reduce or correct your short sight (myopia).
Orthokeratology can also be effective if you have a low degree of astigmatism as well as your short sight. You can tell if you have astigmatism by looking at your glasses prescription. The amount of short sight is written in the “sph” box (with a ‘minus’ if you a short sighted, and a ‘plus’ if you are long sighted), and the amount of astigmatism is written in the “cal” box.
In orthokeratology you wear the contact lenses at night so that you do not have to wear them during the day.