Contact lenses range from simple to extremely complex. Some patients have streamlined prescriptions, and we use spherical soft lenses to correct their vision. Other patients have slight astigmatism and require us to switch over to a toric lens. Modern toric lenses are far more complex and correct vision far easier, which to some means that they are less custom.
When a patient has a large amount of astigmatism or is in need of a multifocal lens, we generally see the fit as more complex; these patients require lenses that some perceive as custom. Extend this into lens fitting for orthokeratology (ortho-k), irregular astigmatism, and keratoconus. These fits may require far more time and far more expertise and experience for the fitting process to be completed. Frankly, all of us can complete these fits. But, are we willing to put in the time and exert the effort? For those who do take the time to learn the craft, we call them specialists who excel in creating custom lenses.
How Complex Is Ortho-k?
Generally, we say that a contact lens fit is custom when it requires us to modify the fit or work extensively to get it just right. If a lens design allows for a streamlined fit but is still complicated, is it still custom, and are we still specialists?
Ortho-k is a prime example of this. With the primary purpose of correcting refractive error and providing patients freedom from glasses and daytime contact lens wear, ortho-k continues to grow as a refractive correction option. Beyond the vision correction, both research and clinicians have reported on its added benefit for slowing down the progression of myopia; several publications have shown that ortho-k may slow the progression of myopia in children by around 50% (Cho et al, 2005; Walline et al, 2009).
As I have traveled the United States and internationally, I am surprised by how few practitioners fit ortho-k. Although most of us are aware of its benefits, many practitioners say: “I don’t specialize in ortho-k” or “I don’t fit those types of custom lenses.” There appears to be a perceived level of complexity around ortho-k that keeps practitioners from fitting the lenses.
In 2009, an ortho-k study was published that revealed the simplicity of fitting these lenses (Eiden et al, 2009). Of the 10 study sites, only two had experience with fitting the lens design used in the study. Using an empirical fitting system, the investigators provided the manifest refraction, keratometry readings, and the corneal diameter. With this lens design, 80.5% of the patients had success with the initial lens fit; if the first lens was not ideal, one lens change resulted in 95.5% success in the lens-wearing eyes.
Not as Complex as You Think
I estimate that I need two to three lens changes on new multifocal patients to achieve success. Most of us fit multifocals. Perhaps we should look at our success with multifocals and at our projected success with ortho-k and consider adding a new “specialty” to our practice.
Just because the fitting process appears to be complex doesn’t mean that it has to be. Ortho-k with proper patient selection, proper consultation, and excellent laboratory support can make custom easy and anyone a specialist. CLS
For references, please visit www.clspectrum.com/references and click on document #262.