PRESCRIBING FOR PRESBYOPIA

PRESBYOPIC LENSES—HOW FAR HAVE WE COME IN 30 YEARS?

CRAIG W. NORMAN, FCLSA

In preparation for this column and in honor of the 30th anniversary of Contact Lens Spectrum, I thought it would be of interest to review what presbyopic contact lens topics were discussed in Contact Lens Spectrum during its inaugural year.

In Founding Editor Neal Bailey’s annual review of the contact lens marketplace in the March 1986 issue, he remarked that “No new bifocal lens designs appeared in 1985, and it is not likely that a new design will appear in 1986. We can only hope that some new material may add utility to a design that formerly was only marginally acceptable.” To me, this was a fascinating statement in that, since then, while lens material has been shown to be important, the design is what is really critical for visual success.

In the July 1986 issue, Winegar and Miller described quite successful results in a study done with a new translating soft lens bifocal on 212 subjects. Yet, as we look in the rearview mirror, this category remains unfulfilled today with very few offerings available globally.

What stood out most to me was a June 1986 article that Friant and Miller titled “When Bifocal Contact Lenses Are Most Likely to Succeed.” While they were also discussing the results of a new bifocal design that had been fit by more than 600 practitioners, what really struck me was the Presbyopic Qualification Checklist they described. This methodology is still pertinent today for an eyecare practitioner attempting to discern whether or not a patient is going to be a good candidate for presbyopia contact lenses.

The Test of Time

Their suggestions have withstood the test of time. First, they broke the checklist into two categories—clinical evaluation and lifestyle/visual demand, similar to how we should approach patient selection today.

Clinical Suggestions They defined three categories: distance correction, amount of toricity, and tear production.

Hyperopes (+1.50D to +6.00D) and myopes (–2.50D to –6.00D of distance correction), especially those who have multiple level of vision demands, are the best candidates, while those who have correction needs at only one point (distance, intermediate, or near) are not expected to perform as well. Low myopes and emmetropes should be avoided (+0.50D to –1.50D).

They suggested that cylinder powers greater than 1.00D have a lesser chance of success. This is one area that has definitely changed during the past three decades, with many options available today. Yet, it remains more challenging compared to spherical multifocal lenses.

Their insight into whether the patient has adequate tears was very perceptive. Only now are we getting closer to having lens materials and treatments to improve compatibility with the ocular surface.

Lifestyle and Visual Demands Friant and Miller (1986) stated that those patients who spend a lot of time in the public eye (where wearing glasses was undesirable for them), as well as those who found spectacles cumbersome for sports and leisure, were good presbyopic contact lens candidates.

In essence, patients don’t really want to wear contact lenses—what they want is to not wear eyeglasses. This was understood even in the 1980s.

So, in 30 years much has changed with presbyopic lens designs, materials, replacement cycles, and fabrication. What hasn’t changed is the importance of proper patient selection. CLS

For references, please visit www.clspectrum.com/references and click on document #250.

Craig Norman is Director of Research, Michigan College of Optometry at Ferris State University. He is a fellow of the Contact Lens Society of America and is an advisor to the GP Lens Institute. He receives honoraria from Bausch + Lomb and Truform Optics. You can reach him at CraigNorman@ferris.edu.