Orthokeratology (also known as Ortho-K) is an excellent alternative to correcting one’s vision without the use of glasses, surgery or eye exercises.
Orthokeratology is basically changing the shape of the front curvature of the eye (cornea) with a specially designed Hard Contact Lens. The effect is very similar to refractive eye surgery (PRK and LASIK), but orthokeratology does not involve surgery.
It is important to understand that the first seven layers of corneal cells (called epithelial cells) can move and change their thicknesses. This is necessary to help with the normal wound healing process of the cornea. Through positive fluid forces (pushing) and negative fluid forces (sucking) under an Ortho-K lens, it manipulates the thickness of these epithelial cells. Thus, Orthokeratology controls the precise movement and placement of these cells.
Below is a histology picture courtesy of Dr Jennifer Choo. It’s demonstrating how the epithelial cells change their thickness under an Ortho-K lens to create the vision correction.
Research done by both Australian and American corneal research institutes have all concluded that Orthokeratology holds no significantly higher risk to corneal health, compared to regular contact lens wear. In addition, it also has a significantly lower risk profile when compared to refractive surgery. This is exactly why the FDA approved Orthokeratology as a safe procedure for the correction of eye refractions (June 2002).
Remember, the effect of Ortho-K is only temporary. To maintain daily vision correction, it is important that you wear the OrthoK lens every night while you sleep. This is due to the epithelial cells moving and changing their thicknesses.
The epithelial cells in the cornea are also replaced every ten days. This rejuvenation of the cornea presents a double edge sword for Orthokeratology. On the one hand, it forces Ortho-K to be a non-permanent correction method, thus every night wear. But on the other hand, it allows the process to be adaptive. Should a person’s prescription change, the Ortho-K lens can also be replaced to correct for the changed prescription. If a patient prefers to halt the process, lens wear can simply be stopped. The cornea will revert to its original shape within 14 – 18 days, allowing for alternative correction methods.