MULTIFOCAL LENSES

Presbyopic Lens Patient Management and Troubleshooting

Strengthen your skills in fitting this currently underserved segment of the market.

By Brooke M. Messer, OD, FSLS; Stephanie L. Woo, OD, FAAO, FSLS; & Edward S. Bennett, OD, MSEd, FAAO, FSLS

It is well established that presbyopes represent the largest untapped segment of the contact lens market (Schwartz, 1999; Edwards, 1999; Bennett and Jurkus, 2005); in fact, we are under-prescribing multifocal contact lenses (Morgan et al, 2011). The number of presbyopes continues to increase as the baby boomers (born between 1946 and 1964) and the Generation X post-baby boomers (born through the mid-70s) are living longer lives (Schwartz, 1999; Studebaker, 2009).

Potential presbyopic contact lens wearers are a combination of current lens wearers who have reached presbyopia and non-lens wearers who have a greater number of vision requirements at varying distances (e.g., tablets, cell phones) and may find spectacles to be inconvenient and over-spectacles to not meet all of their visual needs. In addition, today’s presbyopes are more active and fitness-oriented, making spectacles less than optimal.

What About Monovision?

Monovision continues to be a popular option and is fairly successful, with a success rate of 70% or greater (Westin et al, 2000; Jain et al, 1996). Many practitioners have the perception that monovision is easier to fit and provides uninterrupted vision in each eye individually, whereas multifocal contact lenses are often perceived as complex, difficult to fit, and resulting in less-than-optimum vision.

However, comparison studies have found that, in a forced choice situation, 68% to 76% of lens wearers preferred multifocal contact lenses to monovision (Benjamin, 2007; Richdale et al, 2006; Situ et al, 2003; Johnson et al, 2000). In a study comparing vision performance of GP multifocals, soft multifocals, monovision, and progressive addition spectacle lenses, monovision had the poorest performance in all categories compared, whereas GP multifocals exhibited parity with the spectacle correction (Rajagopalan et al, 2006). Multifocal contact lenses also provide better stereoacuity and near range of clear vision, resulting in a better balance of real-world visual function because binocularity is less disrupted (Gupta et al, 2009).

It is encouraging, therefore, that contact lens prescribing habits have changed in recent years. In an annual survey performed by Contact Lens Spectrum, 70% of practitioners said that they prefer to fit multifocal contact lenses (versus 59% in 2008), whereas 22% prefer monovision (versus 27% in 2008), and 8% prefer over-spectacles (versus 14% in 2008) (Nichols, 2015; Nichols, 2009).

Dispelling the Myths

Improvements in multifocal technology resulting in higher add powers, better optics, and availability in hybrid and scleral lens designs are ongoing. That said, there remain misconceptions about multifocal contact lens use that Dinardo and Fosso (2014) countered very well in a recent publication. Based on their research at the Michigan College of Optometry (MCO) Vision Research Institute (VRI), they concluded the following about multifocal contact lenses:

• Do not rule out patients who have moderate-to-high visual demands.

• Do not rule out advanced presbyopes. In the MCO-VRI multifocal contact lens study, the majority of successful contact lens patients were presbyopes who had >2.00D add (Dinardo et al, 2014).

• Do not rule out over-readers. It is important to never promise that over-glasses will never be necessary. In the MCO-VRI study, 25% of the successful multifocal contact lens-wearing subjects wore over-readers for fine print and did not mind doing so.

• Patients do not need to be previous single-vision wearers to be successful. In the MCO-VRI study, almost half of the subjects were first-time wearers.

• Occasional wear is an option. They found in the MCO-VRI study that occasional wear was both common and successful in daily disposable multifocal contact lens wearers.

• Multifocal lenses improve quality of life. Successful multifocal contact lens wearers in the study felt better about their physical appearance. Their general happiness also increased, as did their ability to perform desired daily activities.

Presbyopic Lens Selection

When advising any potential presbyopic contact lens wearer, it is important to present all of the options (i.e., single vision, monovision, and multifocals), although we tend to emphasize the multifocal option for the reasons mentioned previously.

Bennett and Quinn (2014) reviewed which multifocal option would be preferred in many different situations. For ease of fitting, initial comfort, and occasional wear, soft multifocals—especially daily disposable for occasional wear—are preferable. For ease of fitting and high quality of vision, empirical fitting of aspheric GP multifocals is recommended. Segmented, translating bifocals or multifocals are recommended for unparalleled vision at distance and near. Hybrid and scleral multifocal designs can provide good initial comfort and vision surpassing that of soft multifocals.

GP Multifocals

Patients desiring good visual acuity, including individuals who are not satisfied with their vision from soft multifocal contact lenses or monovision, are good candidates for GP multifocals. The primary designs in use today are aspheric multifocals and segmented, translating lenses, with some designs having a concentric or annular component. To determine which specific design to use, it is important to consider patient goals, pupil diameter, and lower lid position (Bennett and Henry, 2014).

Patients desiring good vision at all distances and, in particular, who frequently use a tablet or laptop computer are good candidates for an aspheric multifocal. The exception would be those individuals who want uninterrupted vision at distance and near; in that case, a segmented translating multifocal would be indicated. Individuals who have a larger-than-average pupil diameter (i.e., ≥6mm) in normal room illumination are not good candidates for an aspheric multifocal due to the resulting glare and blur in low illumination. Individuals who have a low lower lid (i.e., ≥1mm below the lower limbus) are not good candidates for segmented, translating designs because of absent or limited lens translation when viewing inferiorly.

Aspheric Multifocals Numerous improvements in aspheric designs in recent years have resulted in better optics, higher add powers, less risk of corneal molding, and the introduction of post-surgical lens designs. These center-distance lens designs still utilize simultaneous vision; therefore, good centration and limited movement with the blink are important.

Historically, aspheric multifocals have incorporated asphericity on the back surface and were typically fit 1.00D to 1.50D steeper than “K.” Decentration of these posterior designs, especially superiorly, could cause corneal molding and distortion. Ultimately, modified designs were introduced in which additional add power could be incorporated on the front surface—typically in the paracentral-midperipheral region, such that the lens would shift into this zone with downward gaze—for moderate-to-highly presbyopic patients. Some of these designs also have a slight amount of asphericity on the back surface, allowing for them to be fit with, or close to, an “on K” base curve selection. Front-surface aspheric designs can also incorporate a higher amount of add power compared to back-surface designs (Norman et al, 2008).

A benefit of aspheric GP designs versus most segmented designs is that they can be fit empirically with good first-fit success. In fact, it was found that only 42% of 710 aspheric multifocal lenses fit in a large contact lens practice were returned in a three-year period (Blanchard, 2012). In addition, in a workshop setting in which six different aspheric lens designs were empirically ordered for participating subjects, all six were quite successful (Norman, 2014).

It is important to note that every laboratory has several aspheric multifocal designs, all of which are different; laboratory consultants can work with you to optimize success with lens selection, fitting, and troubleshooting. Notably, if you are not achieving sufficient add power, they can recommend a different design to achieve a patient’s visual goals. Often, if a lens is exhibiting excessive movement with the blink, a steeper base curve radius will result in a better lens-to-cornea fitting relationship.

Segmented, Translating Designs The bar for vision in a multifocal contact lens is at its highest with translating designs. These designs require a diagnostic fitting set (with two exceptions to be discussed later) to achieve an optimum fitting relationship because the position and movement of the lens must be evaluated. The bifocal segment should be located in close proximity to the lower pupil margin; prism ballasting helps position the lens inferiorly, with the edge resting against or near the lower lid margin. This allows the lower lid to push the lens up when the patient looks down, moving the near segment in front of the pupil (Figure 1). To help achieve this fitting relationship, a base curve slightly flatter than “K” often results in a lens that will drop quickly and position inferiorly.

Figure 1. A translating GP multifocal lens being pushed up on the eye by the lower lid as the patient looks down.

Several segmented, translating multifocal designs have been introduced to the market recently to provide vision correction at all distances. These include designs with an aspheric intermediate zone, an executive trifocal design, and a bifocal that has asphericity on the back surface.

In addition, the Expert Progressive design (Essilor) represents the only segmented, translating multifocal design that can be empirically ordered. Its empirically fitted bifocal counterpart, the Bi-Expert design, is available from both Essilor and Art Optical. Once you provide the necessary anatomical measurements, such as lower pupil-lower lid, corneal diameter, pupil diameter, and palpebral fissure width, the first-fit success can be good with empirical fitting of these two segmented, translating designs.

Troubleshooting translating GP multifocal designs is not particularly difficult (Bennett and Luk, 2001). If the lens is rotating excessively, a flatter base curve radius may make it less resistant to the upper lid forces. A lens that is picked up too superiorly with the blink can often be lowered by adding prism. If the lens does not shift upward or translate with inferior gaze, flattening either the base curve radius or the peripheral curve radius will increase the inferior edge clearance and may improve translation due to increased interaction between the lens and lower lid.

GP Multifocal Misperceptions Two misperceptions about GP multifocals are that: 1) they are uncomfortable; and 2) they are unpopular. To address the first issue, a study was performed at the University of Missouri-St. Louis in which subjects wore spherical GP contact lenses, aspheric GP multifocals, and segmented translating GP bifocals (Bennett, 2005). Both the aspheric and segmented designs were initially more comfortable, likely due to the fact that they move on the eye less with the blink compared to a spherical design.

Regarding the second misperception, with a total of 63 aspheric/concentric designs available from 38 laboratories and 40 segmented, translating designs available from 31 laboratories (www.gpli.info), it is evident that GP multifocal lenses are still very much in use today.

Resources The GP Lens Institute (www.gpli.info) offers many resources on GP multifocal contact lenses. Five webinars are available, with a sixth coming in April. In addition, a 17-component module titled “Building Your Practice with GP Bifocals and Multifocals” offers numerous resources for practitioners, staff, and patients, including videos on setting patient expectations and fitting, a fee calculator, scripts for handling patient telephone inquiries, a consumer brochure, and application and removal videos.

Soft Multifocal Lenses

Soft multifocals have been a great addition to our contact lens tool box. The vision technology is much improved over previous generations and includes vision function at the intermediate range. Proper patient education and selection bring success with soft multifocal lenses well within our reach.

Patient Selection The first step in the soft multifocal fitting process is to identify potential candidates. These include current successful contact lens wearers or new contact lens wearers who have a strong motivation to remain free from glasses. Patients who are willing to accept some visual compromise are also more likely to be successful.

From a refractive standpoint, presbyopes who have low hyperopia are great candidates for multifocal lenses, as they tend to function with some blur at distance and are very dependent on reading glasses for near tasks. Multifocal lenses will likely improve both their near and their distance vision. Moderate-to-high hyperopes, along with most myopes, are also great candidates for multifocal lenses, as they require a definite correction at both distance and near.

Challenging patients are those who have moderate myopia and are accustomed to removing their glasses to read. Adaptation to the multifocal optics is particularly difficult for them because they are accustomed to seeing very clearly during their near tasks. Take extra time during the patient education process to help you determine whether such patients are sufficiently motivated to wear and adapt to their soft multifocal contact lenses.

Lastly, patients who have little-to-no astigmatism are better candidates for soft multifocals compared to those who have moderate-to-high astigmatism, but this doesn’t mean that you can’t have success fitting soft multifocals on patients who have higher astigmatism. Both frequent replacement and custom toric multifocal lenses are available.

Once you identify potential candidates, discuss multifocal contact lenses and how they can improve daily function and decrease dependency on reading glasses. The discussion should include a description of the lenses and how they work, that there are multiple designs available to customize the fit and vision to their needs, and that adaptation to this vision technology is required. By setting the stage ahead of time, patients will be more relaxed and open to what the lenses can provide.

When describing soft multifocal contact lenses, you can explain that the lenses provide both near and distance optics to the eye at the same time, and the brain will interpret what images to see clearly. Due to this “simultaneous vision,” there may be times when images have a softer edge or overall appearance, and there may be some halos around lights in dim conditions. But, in exchange for those aberrations in their vision, they will gain freedom from reading glasses. You can then explain that the optics in progressive spectacle lenses are split into different areas of the lens, which allows for a more defined set of optics to enter the eye; patients should not compare their vision with the soft multifocal contact lenses to their vision with the progressive spectacles because the optics are completely different. Prior to applying the trial lenses, you can also educate patients that they will experience improved performance over the first few weeks as they adapt to their new lenses.

As much of this conversation can appear to emphasize the less desirable side of multifocal contact lenses, it’s important to understand patients’ goals and to communicate to them how these lenses will improve their experience and function during their desired tasks. A common explanation used with patients is the “80/20 Rule,” which helps remind them that our goal with multifocal lenses should be to function well during 80% of their daily activities, with 10% of distance tasks being less clear compared to their single-vision lenses, and they may need additional magnification for 10% of near tasks.

Fitting and Troubleshooting To begin the lens selection process, determine a patient’s dominant eye by your method of choice. A popular way to do this is to hold a +1.50D loose lens over each eye while patients wear their glasses or distance vision contact lenses; the dominant eye will have blurrier vision through the loose lens. Determining the dominant eye is important for optimizing vision function and for troubleshooting. Next, determine which lens modality and material is most appropriate for each patient’s lifestyle and vision correction needs. Soft lenses are available in a variety of lens materials, including silicone hydrogels that are approved for overnight wear, and in all lens replacement schedules.

After determining the lens type, consider selecting your first trial lens with an add power that is slightly less than the spectacle add power to keep patients’ distance vision relatively clear. Then explain that you have selected a lens with a slightly weak reading power, which will be adjusted as needed. This lets patients know that multiple lenses may be needed during the visit to optimize their vision, and not to panic if they can’t quite see well enough at near with the first lenses.

Once you apply the lenses, use loose lenses to over-refract the dominant eye to optimize distance vision and to over-refract the nondominant eye to improve near vision. When using the loose lenses, encourage patients to keep both eyes open, as vision quality is improved when binocular. Because of the add zones in multifocal lenses, patients may interpret more minus power in an over-refraction as being more clear, so be sure that they are actually gaining letters on the acuity chart and not just improved contrast before adjusting lens powers.

Finding the appropriate balance between the two eyes is different for each patient, and it may take some extended chair time or an additional follow-up visit to further troubleshoot their vision demands. For patients who have struggled with adapting to monovision, try to keep the disparity between the two eyes to a minimum. You can do this by optimizing vision in each eye, then adding near power in each eye until the distance vision is too compromised.

For patients who were previously successful in monovision and are now looking for improved intermediate function, one method is to prescribe a low add in the dominant eye to ensure that their distance vision remains crisp, which should make pushing plus power on the nondominant eye easily accepted.

It is also helpful to utilize real-life tools when adjusting lens powers, such as cell phones for near adjustments and looking out a window rather than at an acuity chart for distance vision modifications. Also, if you have reached an endpoint with patients in the office for the day, encourage them to try their lenses in their normal workspace and to take note of where they could use a vision adjustment. Let them know that it is acceptable to return for a follow-up visit to make small adjustments. Many patients worry about their distance vision in the examination room, but they often find that they actually see quite well when driving. They usually return to the office seeking increased reading power.

When fitting patients who have moderate-to-high astigmatism with a multifocal toric design, one tip to a successful fitting is to utilize the single-vision toric lens first to fine-tune the distance prescription, rotation, and stability of the lens. After achieving a stable distance vision lens, then choose the multifocal option. If the toric single-vision lens is unsuccessful, consider a custom soft toric lens.

As our presbyopic population grows, so does the demand for practitioners willing to spend the time to fit a well-performing soft multifocal lens. Taking a few extra minutes at the first visit to make lens adjustments can make a huge difference in the success of your patients. Improving your skills in prescribing multifocal lenses is a great way to increase your confidence and success with the modality, which in turn will build patient loyalty and word-of-mouth referrals.

Hybrid and Scleral Multifocal Lenses

Some of the most exciting developments in multifocal contact lenses are in hybrid and scleral lens designs. These highly customized lenses may offer better vision to patients who are unsuccessful in other designs. Keeping up with the latest technology and offering your patients more choices for their vision correction can help your practice grow and keep your patients satisfied.

Hybrid Contact Lenses Presbyopic patients who have astigmatism have limited options when it comes to standard soft lenses. Hybrid multifocals can be a great option for these patients. Hybrid multifocals are made up of a GP center and a soft lens skirt (Figure 2), which combines the vision of a GP lens with the comfort of a soft lens.

Figure 2. A hybrid contact lens has a GP lens center and a soft hydrogel skirt.

Hybrid lenses offer a number of advantages. They can correct presbyopia and astigmatism. In addition, they are able to correct corneal astigmatism without a toric ballast system, so lens rotation is not an issue. Because a hybrid lens is a more custom design compared to a standard contact lens, it is likely to provide better vision. Hybrid multifocals can be created with just keratometry values and manifest refraction. They offer dissatisfied patients another option, which can be great for patient loyalty. Hybrid lenses are available only through eyecare practitioners, so patients will not be able to take their contact lens prescription and fill it with a mass distributer, which can also help with patient retention. The fitting process has been streamlined over the years, and it is best to order lenses empirically to start with.

There are some disadvantages. Hybrid lenses are only able to correct corneal cylinder; if lenticular cylinder exists, a hybrid lens may not be the best choice. Hybrid lenses can cost more compared to traditional soft or GP lenses, and the fitting fee is usually more expensive compared to traditional fittings. These financial issues should be dealt with prior to contact lens fitting. Hybrid lenses are applied and removed a bit differently from other lenses, so patients may need additional training. Patients unwilling to try a different lens modality are not good candidates for a hybrid lens. Keep in mind that hybrid multifocals work best on regular corneas, so consider a different lens design for patients who have any corneal irregularity.

Hybrid multifocal candidates include:

• Presbyopic patients who have corneal astigmatism.

• Patients who want to try GP multifocals but are concerned about the comfort.

• Patients who have tried soft multifocals but want to see whether their vision can be improved.

• Patients desiring less dependence on glasses.

• Patients unhappy with their current lens design.

If patients are unhappy with their current form of vision correction, or they want to explore new technology, consider recommending hybrid lenses. Explain to patients how customizable hybrid lenses are. You could say, “This is a new type of contact lens that you’ve never tried before. The shape of your eye and your exact prescription are used to design the lens, so it is extremely customized.”

Hybrid lenses usually have excellent warranties. This may also help in encouraging patients to consider them. If you explain that there is minimal financial risk involved, they may be more willing to try it.

Scleral Multifocal Lenses Among the exciting new designs in presbyopic contact lenses are scleral multifocal lenses. Scleral lenses are larger compared to corneal GPs and are known for their excellent centration and comfort. Scleral lens stability and quality of optics are great as well. Most scleral lens designs vault the cornea completely (Figure 3), which takes the cornea out of the fitting process. The fluid layer between the cornea and the lens can serve as a treatment for dry eyes as well.

Figure 3. Scleral lenses have a larger diameter to provide central clearance.

Advantages of scleral multifocal lenses include that they can be fit on both regular and irregular corneas, which makes them a possible option for many patients. Scleral lenses also offer good comfort and vision. Because they are very customizable, patients are able to achieve good, functional vision. Your patients will know that you are on the cutting edge of technology when you offer this unique lens type.

One disadvantage is that scleral lens fitting fees and devices are usually more expensive compared to other GP or soft multifocal designs, which could deter patients. The fitting process also can be more time consuming compared to other types of contact lens fits, and several follow-up appointments may be necessary to get the best lens. Discussing the amount of time involved prior to fitting can help prevent patient frustration. Troubleshooting scleral lenses may become tedious and time consuming, and both practitioners and patients can start to get aggravated.

Good candidates for scleral multifocal contact lenses include:

• Patients who have irregular astigmatism. Patients who have irregular astigmatism and desire more freedom from reading glasses can be excellent candidates. Helping these patients achieve functional vision for distance and near can be very rewarding.

• Patients who have normal corneas. Many scleral lens manufacturers have developed scleral designs for normal corneas. The base curves, shapes, and diameters are slightly different from scleral contact lenses created for irregular corneas, and the fitting process is usually quicker due to the predictability of normal-shaped corneas.

• Patients who have dry eye symptoms or who experience contact lens dryness. The tear chamber helps to bathe the cornea in liquid during wearing time, which can reduce or eliminate dry eye symptoms.

• Post-refractive surgery patients (e.g., post-LASIK or post-radial keratotomy). Post-refractive surgery patients are some of the most successful patients with scleral multifocals. Think about it, these patients underwent refractive surgery in the first place because they did not want to wear glasses! They are usually quite motivated to get out of glasses once again.

Poor candidates for scleral multifocal contact lenses include:

• Patients who have high/unreal expectations. Patients who have very high expectations for their vision may be disappointed with any multifocal design. Be sure to outline what the lenses can and cannot do and to set realistic expectations.

• Patients who have significant vision loss. Patients who are unable to achieve 20/50 vision or better are not the best candidates for multifocals. Because the eye is compromised in some way, the multifocal optics will likely distort their vision even more.

• Patients who have scarring. Patients who have significant scarring are probably not good candidates for multifocal sclerals because they may experience significant glare and halos.

• Patients unwilling to try a new lens modality. Scleral lens application, removal, and care is different compared to any other lens modality, and patients unwilling to try something new are not good candidates.

• Patients wanting to leave with a multifocal contact lens today. Multifocal scleral lenses are all custom orders, so they can take one to two weeks to fabricate and ship.

Scleral contact lenses do not translate, so most multifocal scleral lenses have concentric or aspheric designs. Most have a center-near design, which is similar to other soft and GP multifocals. Multifocal scleral lenses are very customizable; the base curve, power, edge, and diameter can be altered if the fit needs adjusting. Many labs even have front-surface toric optics and toric peripheries to give your patients a truly custom lens.

Multifocal scleral lenses are easy to order. Fit your patient with a scleral lens from your diagnostic set, perform an over-refraction (including add power), and speak with a consultant to help design the lens.

Multifocal hybrid and scleral contact lens designs are always improving. They will likely become contact lenses of choice in the future for many presbyopic patients. More customization and comfort allow patients to feel their best while achieving great, functional vision.

What Does the Future Hold?

We surveyed experts in the industry about where they thought the multifocal contact lens market was headed in the next two to five years. The sidebar “The Future of Multifocal Contact Lenses” (on page 27) shows their responses.

There is potential for soft multifocal contact lenses to improve, not only through expanded parameters but also with optics that account for line of sight, decentration, pupil diameter, and spherical aberration (Charman, 2014; Brujic, 2015; Plainis et al, 2013; Kollbaum and Bradley, 2014). Multifocal scleral designs should continue to improve while also optimizing optics to account for decentration, as is the case with other simultaneous vision multifocal lens designs. Corneal reshaping may also become a more viable option for presbyopes, and daily disposables, GP designs, and hybrids should continue to improve in the next few years. CLS

Acknowledgements: Josh Adams; Doug Benoit, OD; Raymond Brill, OD, MBA, FAAO, FOAA; Mile Brujic, OD; Clark Chang, OD; Robert Davis, OD; Greg DeNaeyer, OD; Tim Edrington, OD, MS; Barry Eiden, OD; Jason Jedlicka, OD; John Laurent, OD, PhD; Michael Lipson, OD; Ken Maller, OD; Bob Maynard, OD; Bruce Morgan, OD; Tom Quinn, OD, MS; Phyllis Rakow, FCLSA; Renee Reeder, OD; Jack Schaeffer, OD; Jeff Sonsino, OD; Jan Svochak; and Eef van der Worp, BOptom, PhD.

For references, please visit www.clspectrum.com/references and click on document #232.