prescribing for presbyopia
GP Designs for Mature Presbyopes
BY CRAIG W. NORMAN, FCLSA
Having been associated with one clinical practice for more than 30 years, I've come to the realization that your contact lens practice grows old with you. Whereas once most patients I'd interact with were in need of single vision contact lenses, today the practice has a much higher percentage of patients in the presbyopic age demographic. In fact, it is skewing even more toward the more mature presbyopic patients who are 55 years old or older.
This group poses some challenges, of course — drier eyes, sagging and looser lids, more medication use, etc. — but often has an interest in beginning or continuing contact lens wear.
Options for Mature Presbyopes
Luckily, many options are available to help us manage these patients in soft, hybrid and GP designs. While we use all of these lens types in our practice, we have a higher percentage of GP lens wearers compared to many other practices. Because many of these GP wearers are becoming mature presbyopes, we often use translating designs for their correction.
Aspheric or concentric distance (rotational) designs are our first choice for GP wearers and usually provide excellent visual results. For those patients for whom we need more add power, such as the mature presbyopes, translating bifocals (non-rotational ballasted designs) are an excellent alternative.
We have many good lenses in this category — Truform Optics' Llevations and Solitaire, X-Cel Contacts' Solutions Bifocal, Fused Contacts' Tangent Streak, to name a few — that are quite successful.
Figure 1. Bi Expert non-rotational GP lens design. Note the "dots" that designate the seg height and the steep fluorescein pattern, which facilitates rapid movement of the lens back to its proper position after blinking.
New Option Comes to the U.S.
Recently I had the opportunity to evaluate a translating GP bifocal that is new to the U.S. market — the Bi Expert design.
This lens, which originates from the French contact lens company Precilens and is available in the United States through Art Optical Contact Lens, is unique in this category in that it utilizes a patented slab-off technology that results in a 360-degree uniform edge profile. It's non-truncated and can be fabricated thinner than some other lenses in this category.
We evaluated this lens on 13 patients who were a mix of previous single vision GP and soft contact lens wearers as well as patients who were presently wearing GP multifocals and bifocals. As of this writing, 10 of the 13 are successfully wearing the design with good vision, comfort and overall wearability.
I found some qualities of Bi Expert of interest. The reduced lens thickness resulted in improved comfort in patients we evaluated who were wearing other non-rotational designs. The segment location "dots" (Figure 1) made it easy to find the seg height and amount of rotation (if any). Also, the fitting philosophy is a little different in that the base curve is chosen steeper compared to similar designs to facilitate rapid vertical lens movement during blinking to quickly bring the distance and near optical portions back to their proper positions.
Consider this lens and other non-rotational GP bifocals for your mature presbyopes. CLS
Craig Norman is director of the Contact Lens Section at the South Bend Clinic in South Bend, Indiana. He is a fellow of the Contact Lens Society of America and is an advisor to the GP Lens Institute. He is also a consultant to B&L.