Prescribing for Presbyopia
An Overview of Correction Options for Presbyopia
BY DOUGLAS P. BENOIT, OD, FAAO
Welcome to my inaugural Prescribing for Presbyopia column. This series will explore different approaches to correcting the visual challenges of presbyopia. Because this publication is contact lens-focused, we will primarily explore this modality. However, there are non-contact lens methods that are worthy of discussion.
The simplest approach is spectacles, with a number of choices that can bring vision into sharp focus for all distances. However, patients often do not want to wear glasses; they look to alternatives such as contact lenses and refractive surgical procedures.
A brief, not all-inclusive discussion of the latter is appropriate. Conductive keratoplasty uses radio waves to change the corneal shape, usually in the nondominant eye, to improve near vision. LASIK can be performed on the dominant eye in myopic patients to create a monovision effect. There are even multifocal LASIK procedures performed on the nondominant eye that create far, intermediate, and near zones to correct presbyopia.
A more recent development, corneal inlays are placed in the anterior cornea (deep epithelium/anterior stroma) of the nondominant eye to decrease the entrance pupil aperture and create an increased depth of focus. There are also bifocal/multifocal intraocular lens implants that can be used in cataract patients to enhance near vision after cataract removal or in non-cataract patients undergoing a clear lens extraction.
At the 2015 American Academy of Optometry meeting, a presentation (Weiss et al, 2015) discussed animal studies in which the clouded crystalline lens material was removed (preserving the capsule) and replaced with a substance of similar refractive index. This technique provided clear vision at distance and allowed the accommodative system to work again, providing near focus. Human trials will begin in 2016.
For contact lens options, first would be distance lenses with reading glasses over them. The reverse can also be done, but this is not used frequently. However, as mentioned previously, patients often do not want to wear glasses.
Next is monovision. Here, the dominant eye is corrected for distance, and the nondominant eye is corrected for near. Issues such as decreased depth perception can limit monovision’s usefulness.
Bifocal and multifocal contact lens options have been around since the late 1940s. These are underutilized; whether due to the perceived complexity of these designs, or to poor experiences with early designs, many practitioners do not use bifocals/multifocals as their primary choice. Patients often do not hear about them from their practitioner, but rather from friends who wear them. Hopefully, this column will convince readers that these lenses are worthy of their attention.
What’s in Store
My future columns will explore contact lens design options for correcting presbyopia, including simultaneous image designs, alternating image designs, soft lens options, and GP options. We will look at factors to consider when evaluating presbyopic patients, including refractive status and physiologic condition, vocation and avocation, etc. We will create a decision tree to allow a systematic approach to fitting these patients. Stay tuned! CLS
For references, please visit www.clspectrum.com/references and click on document #243.
Dr. Benoit is the senior optometrist with Concord Eye Center, a multi-subspecialty ophthalmology group in Concord, NH. He is a Diplomate of the American Academy of Optometry’s Section on Cornea, Contact Lenses and Refractive Technologies, currently the Special Advisor for the section. Dr. Benoit is a Distinguished Practitioner and Fellow in the National Academies of Practice-Optometry Section and is a Diplomate of the American Board of Optometry. He is also on the Advisory Board of the GPLI and is the 2016 GPLI Practitioner of the Year. Dr. Benoit is a consultant to, and clinical investigator for, Alcon.