contact lenses

Please Presbyopes in Contact Lenses

To satisfy these patients, be knowledgeable of the patient's visual and lifestyle needs, current fitting trends and pertinent patient education.

DIANNE M. ANDERSON, O.D., F.A.A.O., Aurora, Ill.

Because presbyopic patients expect their contact lenses to provide them with the same crisp vision that their spectacles provide, satisfying this patient population with contact lens wear can be extremely challenging.

Emmetropic presbyopes can be even more challenging with contact lens wear. After all, these patients, who suddenly have difficulty seeing near once they turn 40, have never worn any form of eye correction before. As a result, they require extra time for contact lens training (i.e. placing the lens in their eye, etc.); they may not be able to see the chosen contact lens, and monovision or multifocal wear may compromise their personally prized distance vision.

As a practitioner who fits several presbyopic patients in contact lens wear and has retained these patients and attracted new ones, I can tell you there are four keys to satisfying these demanding patients: (1) a knowledge of the patient's visual and lifestyle needs; (2) a knowledge of the current fitting trends, (3) a knowledge of the currently available products designed for these trends; and (4) providing the education required to ensure patients aren't surprised, and, as a result, dissatisfied with the outcome of a fitting.

Satisfying presbyopic patients — in particular — with contact lens wear, can be extremely rewarding personally. This is because you've played a role in improving their quality of life (i.e. their desire to maintain a youthful appearance, freedom from multiple pairs of readers and the ability to participate in activities, such as sports, unencumbered by spectacle wear).

In addition, meeting these patients' needs can be very lucrative for your practice. This is because baby boomers tend to have disposable income. In fact, as a population, they account for almost $230 billion in sales for consumer packaged good products, representing 55% of total U.S. sales, says a recent Hallmark Channel/Nielsen Company study.

Here, I discuss the current presbyopic contact lens fitting trends, the best candidates for these trends (based on visual and lifestyle needs) and the necessary patient education related to each.

You can apply the following five trends to any lens type (i.e. soft, spherical, aspheric or toric, GP or hybrid). Regardless of lens type, though, you must determine the patient's dominant eye to ensure the chosen presbyopic lens wear doesn't put unnecessary stress on the patient's visual system.

Regardless of which fit you choose, always let patients know that the fits are subjective, and that despite great strides in technology, no product is perfect. Then, tell them that because of this fact, you're counting on them to inform you of any problems they may encounter, so you can work with them to resolve these issues.

1. Standard monovision

With this type of presbyopic contact lens wear, you fit the patient in one single-vision lens to correct her distance vision and one single-vision lens to correct her near vision. The ideal candidates for this lens: those whose job and/or lifestyle require them to see at all distances for short periods of time without depth perception.

For instance, teachers, who, by virtue of their job, are required to move throughout the classroom and vary their focus are ideal candidates for standard monovision lenses.

Something to keep in mind: Standard monovision fits are extremely convenient for both you and the patient because you can keep the patient in her current lens material. You just have to adjust the lens power for stronger near vision in the non-dominant eye. Further, if the patient is new to contact lens wear (i.e. an emmetropic presbyopic patient), you aren't confined to a specific lens modality and design.

To manage this patient's expectations, educate her prior to the fit that standard monovision isn't going to duplicate the clear optics of her spectacles, and that she must be willing to make visual compromises. Specifically, inform the patient that the eye (i.e. the dominant one) you fit in the distance lens will view near objects as a bit blurry, and the eye you fit in the near lens will view distance objects a bit blurry as well. In fact, because of the differences between the two lenses, patients who have a substantially lower visual acuity in one eye vs. the other aren't good candidates for this lens modality.

Also, educate the patient that the lenses will require a period of neuroadaptation (usually one to two weeks) as a result of the brain adapting to the loss of binocularity.

Consider prescribing monovision with GP lenses for patients who have large amounts of astigmatism. This is because GP lenses mask great amounts of cylinder. Most designs can correct up to 2.75D of astigmatism. Recommend toric GP designs for cylinder values greater than 2.75D to account for residual astigmatism and provide a better fit. If the patient's astigmatism is corneal as well as refractive, consider monovision with an aspheric GP design.

Another option: Monovision orthokeratology. This is often ideal for presbyopic patients who experience decreased contact lens wearing time as a result of soft contact lens-induced dryness. (As a brief aside, prescribe a hydrogen-peroxide-based disinfecting solution, a separate daily cleaner and preservative-free lubricant eye drops to all mild to moderately dry patients. Further, always educate these patients that decreased wearing time may be a possibility.)

Most presbyopic patients began contact lens wear in GP lenses. Nevertheless, always have a thorough knowledge of the patient's history just to be sure. Again, a surprised patient is often a dissatisfied patient.

2. Modified monovision

This lens wear is for the standard monovision patient who presents complaining she can't see as well in the distance or near as she once did with standard monovision. You fit the patient in a multifocal lens on one eye and a single-vision (distance or near) lens on the other eye. Or, you fit the patient in two multifocal lenses (i.e. one corrected for distance and one corrected for near).

The patient education for modified monovision is the same as standard monovision. As a result, simply reinforce the standard monovision education with the patient during this visit. You don't want the patient to get the impression that modified monovision will make her vision as crisp as it was with spectacles or that she won't experience a period of neuroadaptation again.

3. Binocular multifocal

This presbyopic fit consists of multifocal lenses on both eyes for balanced binocular vision. The ideal candidates for this wear: those whose job and/or lifestyle require them to see distance and near using both eyes and have depth perception. (See "Soft Multifocal Designs and Parameters," below.) For instance, a truck driver is a good candidate for a binocular multifocal, as he requires binocularity. In addition, a presbyopic patient who is unable to neurologically adapt to monovision often adapts well to the multifocal modality.

To manage this patient's expectations, educate her that her vision isn't going to be as clear as her spectacles, and that the binocular multifocal lens design will require visual compromise. For example, if you fit a patient in a design that has the near segment in its center, explain to the patient that she will be looking through the lens' near part in conditions of bright light when the pupil constricts, such as driving during daylight. Recommend that the patient wear sunglasses during these conditions to reduce pupil constriction and improve distance vision. If, on the other hand, you fit a patient in a design that has the distance segment in the center, educate her that in dim illumination, she may experience halos due to pupil dilation beyond the distance zone of the contact lens. The bottom line: Patients need to understand that these lens designs are pupil-size dependent, and this type of lens wear subjects them to visual fluctuation depending on their working and living conditions.

4. Aspheric GP multifocal

I've found that this lens works well if the patient's cylinder is corneal as well as refractive. Most of the currently available designs can correct up to 2.75D of cylinder. If the patient's cylinder values are greater than 2.75D, recommend a toric GP design to avoid residual astigmatism. GP multifocal lenses cost more than monofocal GP lenses, so be upfront with the patient about the cost differential to give her an opportunity to decide whether she'd like to try them. Doing so sends a clear message to the patient that you're invested in her satisfaction and not your wallet. Several new aspheric multifocal GP lens designs and materials are available. Consult with your GP lab, or search their Web site to obtain the latest information.

The latest aspheric multifocal designs incorporate the asphericity on both the anterior and posterior lens surface. The result: a well-fit back surface (which reduces corneal reshaping) and an aspheric front surface (which provides extra add power). Also, these designs enable you to customize the center-distance/intermediate zone for the patient's pupil size.

Many GP lens companies have designed bi-aspheric multifocal GP lenses, which they've manufactured with state-of-the-art tracing lathes to decrease aberrations inherent with increased add powers. The benefit to these designs is that the add power is a spherical addition on the periphery of the front surface, thereby decreasing the chances of corneal molding and reducing the aberrations traditionally induced by back-surface GP multifocal lens designs.

Two new GP lens materials have recently been created with a high refractive index to improve the effective add power of aspheric multifocal GP designs: Paragon HDS HI 1.54 (Paragon Vision Sciences) and Optimum HR 1.51 (Contamac US, Inc).

5. Enhanced multifocal

As with the standard monovision patient who presents needing modified monovision, the enhanced multifocal is for the binocular multifocal patient who needs a tweak or two to better her vision. Specifically, you enhance one eye for either distance or near.

Also, as is the case with the education for standard monovision and modified monovision patients, the patient education for enhanced multifocal wear is the same as binocular multifocal wear. Therefore, re-emphasize this education to the patient to avoid any surprises with the outcome of the fitting.

Unfortunately, you will never satisfy every one of these patients in contact lens wear. But, by having a knowledge of the patient's visual and lifestyle needs; a knowledge of the current fitting trends and available products for these trends; and managing patient expectations through pertinent education, you have an excellent chance of satisfying several of these patients. The result: personal and financial reward. OM

Dr. Anderson practices in suburban Chicago, specializing in orthokeratology, keratoconus, post-surgical lens fits and anterior segment disease. E-mail her at dianne.anderson@com cast.net.