Orthokeratology
Created | Updated Dec 23, 2002
Orthokeratology is the name of a procedure used to correct myopia (short-sightedness) using contact lenses. It is temporary and relatively painless. The procedure has its roots in a traditional Chinese technique for correcting myopia. The sufferer would sleep with small bags of sand on their eyes. As myopia is caused by a lengthening of the eyeball, the weight of the sandbags would temporarily flatten the eye, restoring normal vision for a time.
This is the principle on which orthokeratology operates. Instead of using sandbags, contact lenses are worn on the eyes during sleep.* Overnight, the contact lens places pressure on the layer of tears covering the cornea, and thus myopia is reduced.
The lens itself is of the rigid gas-permeable type: it is relatively hard, making it uncomfortable for daily wear but allowing pressure to be applied. Oxygen can penetrate the lens membrane, preventing eye infections. Lenses are changed yearly, but can last longer if cared for properly. They can also fracture during cleaning or if handled carelessly, rendering them useless - even hazardous.
Vision correction is initially minor, although results improve with regular wear. A good result is the restoration of near-perfect vision, lasting for a period of greater than twenty hours.
Orthokeratology can become expensive, but is not permanent like laser surgery, and without the drawbacks of glasses. Their use can be discontinued at any time and vision will slowly return to pre-treatment levels. They are a reliable method of vision correction which allow one to carry out many activities that glasses prohibit, such as swimming and contact sports, but without the expense or danger of laser surgery.
More information on the procedure, and the subtle difference between types of orthokeratology, can be found at this location.
