The Ortho-K Contact Lens and How It Works

ORTHOKERATOLOGY FOR RESHAPING THE CORNEA is the most technologically advanced non-invasive therapy for the correction of myopia available today. Much of its recent success comes from the new, high-tech Orthokeratology lenses. Thousands of ortho-K procedures have been performed with these marvelous lenses and the number is growing daily.

How Does the Ortho-K Contact Lens Work?

Many patients ask, "How can a specially designed and manufactured contact lens possibly improve my vision?" As mentioned earlier, Ortho-K contact lenses gently reshape the central curvature of the cornea. This reshaping reduces and causes more spherical shape, to reduce or eliminate nearsightedness and astigmatism.

The high-tech, therapeutic lenses are manufactured using state-of-the-art lathes. Until a few years ago it was not possible to manufacture these special lenses, the technology is truly revolutionary. The new lenses allow as much as twice the vision improvement in considerably less time.

Here are some of the specifics about the lens design.

The design you see above is made from a rigid, gas-permeable material that allows enough oxygen to pass through the lens, so the cornea receives sufficient oxygen to remain healthy even while the patient is sleeping. The accelerated Ortho-K contact lens design allows for night wear. Improvements now occur in hours, days, and weeks versus years with previous Ortho-K procedures. Many people will notice significant improvement after the first night of lens wear.

The currently used, state-of-the-art Ortho-K lenses have a central base curve that fits significantly flatter than the central curvature of the cornea. This lens/cornea relationship creates a stimulus to reduce the central corneal curvature thus resulting in improved myopia and unaided vision. Outside the base curve is a steep zone which allows the flatter central corneal curvature to shift to the mid-peripheral cornea.

The alignment curve of the lens causes it to position properly. The flat peripheral curves of the lens provide a reservoir of tears which supply oxygen to the cornea.

This special, unique lens design is manufactured in labs outfitted with special computerized lathes. Not every lab with such equipment is capable of fabricating these lenses with the precision necessary. This truly revolutionary procedure requires everyone involved—doctor, patient and lab technician—to perform with utmost precision in order to attain the best possible result.

The Lens Fit
Today’s comfortable Orthokeratology lenses are fit so as to not compromise the health of the cornea. The new Ortho-K procedure allows the lens to center well on the cornea. The better fitting lens allows improved control and centration of the treatment zone.

Corneal Adaptation and Rapid Change
The ortho-k contact lenses, like all gas permeable lenses, are actually floating on a layer of tears and not pressing on the eye as one would think. The initial awareness of the lens on the eye is actually felt by the lids during a blink. Comfort improves rapidly, and most wearers of orthokeratology lenses report good comfort within the first few days. It is important to note that the eye does not form a callous. It becomes desensitized, and the brain soon determines that this sensation of a lens on the eye is not detrimental and therefore ignores the sensation. This is much like the process of becoming unaware of wearing a watch or ring, initially they are an annoyance, however the sensations soon go unnoticed.

Visual acuity can improve as much as 50 percent in as little as hours or a couple of days and certainly in weeks. It is common for someone with unaided acuity of 20/200 to experience good vision after their first night of lens wear. With a properly fit lens, these changes are accomplished with no compromise to corneal integrity.

The changes that take place in the first several hours of wear are significant enough to show on Corneal Topography. As discussed earlier, corneal topography is the method of choice to monitor the change in shape and elevations of the entire cornea.

Eight hours of wear a night or twelve hours of day wear is usually sufficient wear to create the desired improvement in vision. It is important to follow, as close as possible, the wearing schedule prescribed by the doctor. Significant variations in lens-wearing time can cause less than ideal results or require longer time periods to reach the best results. Ortho-k lenses are designed to give clear vision while the lenses are worn. If day time wear is used, the patient should always see 20/20 with the lenses on, and have the luxury of seeing well without lenses in days to weeks. If night wear lenses are worn, within the first few weeks, patients are able to see quite well for all their waking hours.