Follow fitting guides, manage expectations with multifocal contacts
Presbyopia is on the rise as our world’s population matures. By next year, the worldwide prevalence is expected to be 1.37 billion (Fricke et al.). As this represents 1,800 presbyopes for each optometrist, it is likely that presbyopic patients will make up a significant part of your practice over the next decade and beyond.
A 50-year-old female patient comes to your practice inquiring about multifocal contact lenses. She has never worn them but is highly motivated to do so. You may be concerned with: chair time, performance, price ... and chair time. Some doctors would fit more patients in multifocals if it took less chair time.
Presbyopic patients can be demanding, but there are ways to maximize efficiency. The first is to determine the dominant eye. Because troubleshooting these lenses almost always involves knowing which eye is dominant, establishing this early will save headaches later in the process.
Another way of maximizing efficiency is to choose the correct multifocal design and power the first time. Optometrists can expect greater than 90% success when using one or two trial lenses (Bauman et al.). This can be achieved with a proper understanding of the fitting guide for each lens. Most companies now have online multifocal contact lens calculators, which include OptiExpert (CooperVision), Contact Lens Virtual Consultant (Alcon) and Contact Lens Fitting Calculator (Vistakon). I have personally found these calculators to be valuable, especially when trying a new design.
Managing expectations on the first visit can save time and reduce subsequent visits. Every presbyopic vision correction option requires compromise, and multifocals are no exception. But multifocals often represent the option with the least amount of sacrifice. Once patients properly understand this concept, they may be more open to visual blur toleration.
It is helpful to inform the patient that these multifocal lens designs are meant to work with both eyes open, and instruct them to resist the urge to cover one eye or the other during the adjustment period. At follow-up visits, we often check distance and near vision with both eyes together.
I rarely make more than one trial lens change at the first visit, as cortical adaptation may take a few days to a few weeks. When I see a patient back for a subsequent visit, I find that an automated over-refraction or careful manual over-refraction is crucial to subsequent changes. In general, I try to use the most amount of plus power in the dominant eye to achieve adequate distance vision and the least amount of plus power in the nondominant eye to achieve adequate near vision.
There are many factors that determine how a lens will perform. The first factor is the design. Most soft multifocal contact lenses are simultaneous vision, which means that the patient will see several distances clearly at the same time. The patient’s job is to focus on the image they are trying to see at that particular moment.
Many patients adapt to this naturally, but some patients need coaching through this process, as they may find the experience disconcerting at first. Lens designs can be center distance or center near. Most commercially available lenses are now center near designs, but center distance lenses still play a significant role. In general, distance-centered multifocal designs do well in emerging to low presbyopia, while near-centered lenses excel with moderate to high amounts of presbyopia.
One of the biggest reasons for failure is lens decentration. Lens decentration may induce third-order aberrations and degrade visual performance. Inadequate centration may also worsen during peripheral gaze. It may be viewed by biomicroscopic observation, but corneal topography may be a powerful diagnostic tool to assess centration. The accompanying map shows the left eye of a patient who is wearing a temporally decentered center-distance design.
Another factor that may affect performance is dry eye or ocular surface disease. Generally speaking, contact lenses will put stress on the ocular surface. Putting a higher stress lens on an already stressed ocular surface may cause unstable vision, resulting in dissatisfaction. Sometimes it is necessary to stabilize the ocular surface with lubricants, topical ophthalmic pharmaceuticals, omega-3 supplements or punctal plugs prior to attempting a contact lens fit or refit.
There are many commercially available multifocal designs available. But sometimes a patient is unsuccessful with all of them. In these cases, a customized multifocal might be an option. Customized multifocals can be found in soft lenses, gas permeables, hybrids and sclerals. Using customized designs, practitioners can alter the power, diameter, base curve and optical zone sizes. Toric presbyopes have traditionally been a challenge to the practitioner, as these patients are more likely to be contact lens dropouts. Fortunately, there are new options being brought to market for these patients.
Practitioners may be uncomfortable with discussing price. Why not just correct the patient for distance and get inexpensive over-the-counter readers? Why not just do monovision? While it is true that multifocal contact lenses add an extra expense, many — if not most — patients are willing to exchange price for convenience. They desire to see like they did before presbyopia became an issue. With manufacturer rebates, most multifocal designs add only $100 to $200 to the price of what patients pay for single vision contact lenses.
Whether it is cosmesis, functionality or frustration with their current situation, motivation remains a key factor in determining a patient’s success. A motivated patient who understands that lens fitting is a process will often experience a positive outcome.
Establishing a level of proficiency with multifocal contact lenses has never been as important as it is right now. We owe it to our presbyopic patients to give them the best chance of success.
Bauman E, Lemp J, Kern J. Material effect on multifocal contact lens fitting of lenses of the same optical design with the same fitting guide. Presented at: British Contact Lens Association Clinical Conference & Exhibition; June 9-11, 2017; Liverpool, U.K.
El-Nimri NW, et al. Optom Vis Sci. 2017;doi:10.1097/OPX.0000000000001127. Fedtke C, et al. Clinical Optometry. 2016;doi:10.2147/OPTO.S108528.
Fricke TR, et al. Ophthalmology. 2018;doi:10.1016/j.ophtha.2018.04.013.
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Michael Cymbor, OD, FAAO, practices at Nittany Eye Associates in State College, Pa. He can be reached at: email@example.com.
Disclosure: Cymbor reports no relevant financial disclosures.