Orthokeratology (ortho-k) is a non-surgical procedure that can reverse the effects of nearsightedness on your vision. Basically, your eye doctor fits your eyes for special contacts made to exactly balance the specific error in your vision. By using a special machine, your eye doctor will “map” the surface of the cornea and use that data to fit you for a type of contact called a gas permeable lens. These lenses are harder, more rigid, and made out of a material that allows more oxygen to pass through the lens to the eye than the average soft lens. The rigidity of the lens is what makes this procedure more permanent than the normal contact lens fitting. The harder lenses actually alter the shape of the cornea, for a limited amount of time, so that you can actually go without them and still be able to see clearly. The procedure is done slowly, with incremental adjustments of the prescription, until the shape of the cornea is more like a normal, healthy eye, and contacts are no longer necessary. It is important to wear them frequently, however, because the reshaping of the eyes is temporary. They will revert back to the irregular shape that causes less-than-perfect vision if you are not diligent about wearing your lenses.
Generally, vision is improved and clear for about a day without the lenses, and after that the eyes will need to be re-shaped. New technological findings in the realm of contact lenses have made it possible for gas permeable lenses to be suitable for overnight wear, so ortho-k has surged in popularity as of late. Patients are now able to wear their contacts while they are sleeping and remove them during waking hours, living unbothered by some of the inconveniences of contact lenses.
The ideal candidate for ortho-k is a nearsighted person with a refractive error of less than -4 or -5, and little to no astigmatism. This procedure is not probably adequate for someone who wants to eliminate contacts altogether—he or she may be looking for LASIK surgery—but it is great for someone who cannot or is unwilling to pay for LASIK, but would like to achieve some of the benefits of lens-free vision.