Don't Forget the Humble GP Sphere
BY JOHN MARK JACKSON, OD, MS, FAAO
Sometimes it's the obvious things in life that elude us. Recent reports show that new cosmetic GP lens fits are on the decline. I've made it my personal mission to see that our graduates are comfortable fitting GP lenses, but I realized recently that I'm guilty of not always offering them to patients when I should.
1. GP lens with even alignment and good lid attachment.
Soft Lens Woes
I recently saw a patient who had a long history of soft toric lens wear and wasn't satisfied with her lenses. She's in her mid-30s and stated that her vision had always been "good enough," but not crisp with her contact lenses. She also noted that previous practitioners had tried numerous lenses with only moderate success. Her manifest prescription was OD –7.00 –1.25 x010 and OS –6.50 –1.25 x170. Her K values were OD 46.00/47.00 @ 102 and OS 46.00/47.00 @ 090. Her ocular tissues were all unremarkable.
We tried several brands of soft toric lenses over time, and she experienced problems with all of them: Excessive rotation, borderline acuity, discomfort from dryness and a "film" that developed on the lenses within a few days. Changing cleaning regimens and makeup didn't help, either.
A Simple Solution
We were all getting frustrated when a student asked, "Why don't we try a pair of GP lenses?" Even though I know better, I inwardly sighed and began a mental list of reasons not to try them (patient nonacceptance and adaptation difficulties being the main ones). I then realized that the student was correct and we hadn't offered the patient the obvious solution to her problem. She had a textbook-perfect situation for successful GP lens wear: About 1.00DC of with-the-rule corneal and refractive astigmatism and an upper lid that covered the limbus, allowing for good lid attachment. We also believed that she would find the lenses easier to care for and to keep clean.
The patient was eager to try something new, so we ordered a pair of lenses with the following parameters: Starlens (X-Cel) design, Paragon HDS material, OD 7.58mm base curve, 9.6mm overall diameter (OAD), –6.00D power; OS 7.58mm base curve, 9.6mm OAD, –5.50D power.
At the dispensing visit, she was a little unsure about the initial lens awareness but claimed that her vision was better than with any lenses she'd tried before (20/15 OU) and even better than with her glasses. The lenses fit well (Figure 1) with even alignment and good lid attachment. We taught her application and removal and lens care techniques, then scheduled her for a follow-up visit a week later.
Like No Other (Soft) Lens
By the next visit, she was wearing the lenses for almost the whole work day. She was thrilled with her vision and was adapting well. She was also pleased with the ease of cleaning and that no "film" developed on the lenses. Her main question was: "Why hasn't anyone offered these lenses before?"
Why indeed. This column regularly discusses GP lens fitting from the simple to the complex, and while complicated fits are fun to read about, sometimes the simple fits are the most rewarding for patients. Offer GP lenses to your patients when they're appropriate - you'll be glad you did.
Dr. Jackson is an assistant professor at Southern College of Optometry where he works in the Advanced Contact Lens Service, teaches courses in contact lenses and performs clinical research.