Is This the New Norm?
Is Prescribing Toric Lenses for Low Cylinder the New Norm?
BY MILE BRUJIC, OD, FAAO, & DAVID L. KADING, OD, FAAO
It is commonly known that most of our patients who have astigmatism have cylinder of less than 0.75D. In fact, the majority of those who have astigmatism have less than 1.25D of cylinder (Young et al, 2011).
So we pose this question: Is it normal to put a patient who has low cylinder, such as a prescription of –4.50 –0.75 x180, in toric lenses? Our guess is that the vast majority of us would initially vertex this patient and prescribe a lens with a spherical equivalent. You could even argue that this would be the best course of action because, indeed, placing a lens with –0.75D of cylinder on this patient would leave him slightly overminused in the cylinder meridian. We could even take this one argument further: why place a toric lens on this patient at all? Toric lenses cost more, take more time to fit, and the patient will not notice the difference.
Toric Contact Lenses Have Come a Long Way
We feel that this begs the question today, should correcting low-cylinder patients with toric contact lenses be the new normal? We believe so. Our industry partners have advanced the stability of toric lenses to such a precise degree that we rarely place more than one lens on our patients’ eyes in the fitting process. In the past, if we had attempted to fit the patient described earlier with a toric contact lens, the process would have looked something like this: allow the lens to settle for 15 minutes, evaluate the lens only to find that it had rotated 10º, do a cross-cylinder calculation (or LARS), place another lens on the patient’s eye, then discover that his acuity is the same with a spherical lens.
We feel that our industry partners have locked down their current generation of toric contact lenses to the point that if you do not have a stable lens within four minutes of lens application, you should consider another brand. Our rationale for this belief comes from our patients; they do not want to put up with unstable vision in their first moments of lens wear.
We Need to Give Patients the Best Possible Vision
Additionally, our patients are looking for high-definition vision. We would never consider leaving a –0.75D cylinder patient uncorrected in spectacles, so why should we do it in his contact lenses when we have tools to fix the problem?
Our mantra is to correct the most amount of prescription possible. Although the spherical power might correct 80% of the refractive error, the low cylinder amount may just make that extra 20% improvement in challenging situations.
We believe that prescribing toric contact lenses for low-cylinder patients is the new norm in most cases. CLS
For references, please visit www.clspectrum.com/references and click on document #231.
Dr. Brujic is a partner of Premier Vision Group, a three-location optometric practice in northwest Ohio. He has received honoraria in the past two years for speaking, writing, participating in an advisory capacity, or research from Alcon Laboratories, Allergan, B+L, Optovue, Nicox, Paragon, SpecialEyes, TelScreen, Transitions, Valeant Pharmaceuticals, Valley Contax, VMax Vision, VSP, and ZeaVision. Dr. Kading owns the Specialty Dry Eye and Contact Lens Center in Seattle, Wash. He is the co-owner of Optometric Insights with Dr. Brujic. He has received honoraria for consulting, performing research, speaking, and/or writing from Alcon Laboratories, Allergan, Bausch + Lomb, Biotissue, Contamac, Essilor, Nicox, Oculus, RPS Detectors, TearScience, Valley Contax, and ZeaVision. Follow him on Twitter @davekading.