The Bare Essentials of Orthokeratology

Orthokeratology is the use of rigid gas-permeable contact lenses, usually worn only at night, to improve vision through the reshaping of the cornea. The idea of correcting vision by reshaping the cornea has been around for a while. George Jessen produced what was almost certainly the first orthokeratology design in the 1960s made from PMMA material, which he promoted as "Orthofocus."

Vision care specialists have described modern orthokeratology as the short-term reduction of myopia by the programmed use of rigid gas-permeable lenses. New contact lens design improvements have speeded up the corneal reshaping procedure and now frequently only one or two pairs of lenses are necessary rather than the previous four to six pairs for the entire process.

Ortho-K is a non-surgical process, and it is used mainly to correct refractive errors such as nearsightedness and astigmatism. With the introduction of space-age polymers, computer-assisted lathes, and technological advancement in the procedure, it is now possible to achieve reduction in myopia in a matter of days. Children and adults can be treated with Ortho-K since the principle of flattening the cornea is helpful for both.

Orthokeratology is still controversial, especially for children. Although not extensively used in the United States, the process is gaining recognition, particularly in countries such as China. The main prohibitive factor is the cost, which is approximately 10 times that of a pair of traditional gas-permeable lenses. Orthokeratology lenses also cause the ocular surface to swell, which may cause the cornea to become vulnerable to the formation of ulcers.

In general, suitable Orthokeratology patients should have:

- Mild to moderate myopia where night therapy is to be used
- Mild "with-the-rule" astigmatism and no "against the rule" or oblique forms of the disease, as current designs tend to increase these types of astigmatism and seem ineffective in reducing it
- No contraindication to overnight lens wear such as diabetes
- A favorable response to a six-hour or an overnight tolerance trial
- Realistic expectations

What's New In Orthokeratology

With the introduction of computer numerically controlled lathes, it is now possible to create almost any type of contact lens. Among the new designs are "reverse-geometry" lenses, whose base curve is flatter than the periphery. Ortho-K patients using these lenses have quite a few advantages: primarily that the results are reversible and the cornea remains intact.

Basic Ortho-K Hygiene

Remember to always wash your hands carefully with a mild soap, rinse them completely and dry them with a lint-free towel before touching the contact lenses. Also remember that you shouldn't wear the lenses around the clock. Dirty contact lens cases are another notorious source of bacterial contamination. Empty the case and rinse it with fresh, sterile rinsing solution and allow it to air dry every day to prevent bacterial growth.