Finding the Best
Lenses for Presbyopes
BY JOSEPH T. BARR, OD, MS,
Last week, a presbyopic colleague from another university asked me about her recent experience with two different bifocal contact lenses. The first type didn't work out. The second type isn't adequate at work but is fine for a night of socializing. I asked her what worked and didn't work with the first pair. She said that those lenses corrected her distance vision but were inadequate for near and computer work. She said that the new pair is poor at near and for the computer and bad for distance.
I asked her if she had ever tried monovision -- one eye for distance and one for near? She said, "No, but my half eyes work fine. I just find them a hassle." I asked, "So you don't need any correction for distance, for driving or for watching a movie or television?" "No," she replied. So I said, "Well then, you really aren't a great bifocal or multifocal contact lens candidate."
That's the way it is with
emmetropes. Everything we do with bifocal or multifocal contact lenses to improve their near vision decreases their distance vision, with the possible exception of optimally fit GP alternating vision lenses.
I hate second guessing other eye doctors. I may talk frankly with a patient, but I never second guess the other practitioner
publically. So I told my colleague that I agreed in general with her doctor's approach of trying multifocals first, but in her case she may be better off with one lens (single vision or
multifocal) on one eye and nothing on the other.
About 15 years ago, a cynical, wise old sage in the contact lens field told me that it's better to prescribe multifocal contact lenses for presbyopic patients because you can charge more for multifocals than you can for
monovision. Let's hope that practitioners don't do this today. We should choose the system that offers the best chance for success. Emmetropes do better with one spherical or one multifocal lens. Some multifocal or bifocal designs are better than others. I believe that center-near lenses work better on hyperopes and center-distance lenses work better on
myopes. "Tweaking" or modifying the power of each lens at distance and near for each patient is crucial. It's also critical to test near vision with reading material (not VA charts) first and then to over-refract to find the best compromise between distance and near power. And don't forget Dave Hansen, OD, FAAO's many comments in past issues about choosing lenses based on pupil size.
Before you dispense lenses for a presbyopic patient, inform him that all corrections for presbyopia are a compromise. The best prescription depends on our best assessment of patient needs and lens type, patient adaptation and our ability to modify the prescription to best fit the patient's needs. So, instruct patients, after they try the first lenses, to tell you when they work, when and why they're a challenge and what isn't pleasing so we can make corrections and create the fewest compromises for each patient.
Contact Lens Spectrum, Issue: November 2004