Is This the New Norm?
Is Monovision the New Norm?
By MILE BRUJIC, OD, FAAO, & DAVID L. KADING, OD, FAAO
For presbyopes looking to focus things better at near, we could prescribe reading glasses over their contact lenses to maintain binocularity. However, patients won’t have the ability to see in the distance when they are wearing their reading glasses, and they must keep track of the reading glasses. Or, we could simply provide them with slightly more plus power in their nondominant eye; this provides the convenience of not requiring reading glasses, but it also disrupts binocularity.
Although many would agree that retaining binocularity is important, we still see a high percentage of patients in monovision. Multifocal lenses, the one option not yet discussed, can provide patients with binocularity as well as the convenience of not requiring supplementary glasses over their contact lenses for near vision. Additionally, we are fortunate that multifocals are now offered in a number of designs and modalities.
Near-Center Aspheric Optical Design As its name implies, the near optics of this simultaneous design multifocal lens are located in the center of the lens and slowly progress to distance optics in its periphery. This design is available as a daily disposable or monthly frequent replacement lens, can incorporate astigmatic correction, and is the design found in the hybrid multifocal lens design.
Distance-Center Alternating Design This lens has its distance optics in the center of the lens and then alternates several times between near and distance optics toward the periphery. This design is available as a two-week frequent replacement lens.
Distance-Center Lens This design has the distance optics in the center of the lens, progressing to near optics in the periphery. This monthly frequent replacement lens is fit binocularly on patients who require low presbyopic correction. For patients requiring high add, this lens design is fit on the dominant eye, with a near-center lens placed on the nondominant eye.
GP Lenses Many of these have an aspheric design with distance optics occupying the center of the lens and progressing to near optics in the periphery. Proper translation of the lens when viewing at near optimizes the acquisition of the near optics in the peripheral portion of the lens. Segmented bifocal designs provide distance optics through the superior portion of a prism-ballasted GP and near optics through the lens’ inferior portion.
Scleral Lenses This lens is available in a multifocal design with the near optics located in the center of the lens, progressing to distance optics in the periphery.
Dividing the optics would seem to have the effect of decreasing the strength of the optical signal reaching the retina for either distance or near targets. But, this design allows the patient to retain binocularity. Research has shown that when patients are fit with either monovision or multifocal contact lenses, although their monocular visual acuities may measure better at a given distance with monovision, patients prefer the multifocal lenses (Richdale et al, 2006; Woods et al, 2014).
With the benefits and options that exist with today’s multifocal lenses, we feel that monovision is not the new norm. With current multifocal technologies and those that will be coming to market in the next several years, we would argue for multifocal lenses for presbyopes as the new norm. CLS
For references, please visit www.clspectrum.com/references and click on document #233.
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. 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.