Article

PRESCRIBING FOR PRESBYOPIA

WHEN MULTIFOCALS FAIL

Multifocal contact lenses are successful in many circumstances for patients who have a range of refractive errors, near demands, accommodative abilities, and ocular surface conditions. However, there are times when patients and practitioners alike struggle to achieve success with multifocal lens performance. In these moments of struggle, failure may seem inevitable—although some considerations may help in moving from impending failure to a more successful outcome.

The Fitting Guide Is (Almost) Always Right

Contact lens companies spend an inordinate amount of time developing and refining their multifocal fitting guides. The fitting guides present the ways in which company internal researchers and product developers, as well as external key accounts, have achieved the greatest success with the products. They should be be initially consulted in the troubleshooting process.

That being said, on rare occasions, deviating from the fitting guide might be necessary to achieve success. Though the fitting guide will result in success in the overwhelming majority of cases—and it is generally suggested to not deviate from it—each patient scenario is different, and their unique distance and near demands may vary.

A potential troubleshooting strategy that may result in a successful outcome is when the near demand and, therefore, the necessary add power becomes great enough that it significantly disrupts distance vision. In this case, a dissimilar add or add profiles over the nondominant eye may be indicated.

Beyond Lens Design

Sometimes patients are seemingly successful with a particular multifocal lens design but are unhappy with comfort or the lens replacement schedule. Knowing which contact lens companies make their proprietary multifocal lens designs in various material and lens replacement schedules can be a powerful tool in achieving success with such patients. Many companies incorporate the same or similar multifocal optical designs with the various material choices within their product portfolio, using essentially the same multifocal lens fitting guide for all.

Don’t Forget Pupil Size

In presenting simultaneous distance and near optics to patients, the optics that are placed over and within the pupil are thought to be the most visually significant. Paying attention to pupil size and making sure that those optics are within patients’ average ambient pupil size ensures that patients receive the necessary optics of a particular multifocal design. Choosing a design in which the optic zone can be modified based on pupil size may result in a more successful outcome.

The same can be said for lens designs that incorporate astigmatism correction. It is tempting to try to compensate for subtle amounts of astigmatism by prescribing the equivalent sphere, but doing so may disrupt patients’ distance and near vision to the point that it results in multifocal failure. If this is the case, consider correcting the astigmatism within the lens by ordering a soft toric multifocal design or, when the astigmatism is present in the cornea, by prescribing a GP multifocal lens design.

Not One-Size-Fits-All

Each presbyopic patient presents a unique clinical challenge. Incorporating some of these strategies may help to move patients who are struggling in multifocal contact lenses to a more successful outcome. CLS