Prescribing Multifocal Contact Lenses
Prescribing Multifocal Contact Lenses
There are ways to increase your prescribing success with your presbyopic patients.
By Clarke D. Newman, OD, FAAO
Regardless of how we look at the numbers surrounding presbyopic contact lens prescribing, we're not doing a very good job. According to research performed by Ciba Vision (Ciba) in 2009, the number of people who need vision correction goes from just under one-half of those individuals in their late 20s to more than 80 percent in those patients older than 60.
These numbers are big. According to the “Demographic Trends in the 20th Century,” the average American in 1900 was a male younger than 23 who lived in a rural area. By 2000, “he” became a “she,” older than 35 living in a city. In 1900, 70 percent of America was younger than 35. By 2000, 54 percent of America was older than 35. Today, one-half of Americans are incipient presbyopes or beyond. Think about that—one-half.
We are getting older and we read more. The need for clear near vision has never been greater. We must fill that need or someone else will. Currently, surgical options are somewhat limited and expensive, but they are improving and they will invariably become less expensive. We also compete against an ever-improving progressive addition lens array and ubiquitous over-the-counter (OTC) readers.
When we again look at the Ciba data, the percentage of each age group that wears contact lenses declines from one-in-four of those 25 to 29 years of age, which represents more than one-half of those needing correction, to less than 1-in-20 of those older than age 60. That represents just under 5 percent of those needing correction. That is a reduction of 10 times market penetration. I'm a clinician; therefore, I haven't calculated the p-values, but I'm going to go out on a limb here and say that that reduction is significant. So, what gives?
The data suggest that many of the same reasons we lose contact lens wearers in the pre-presbyopic age groups are at play for the presbyopic lens wearers as well. We have all read these studies: dryness, redness, convenience, and end-of-day comfort are all factors. However, the rate of loss as a percentage of each age group drops linearly after age 40 while the number of those who need correction grows linearly. So, presbyopia has to play an important role here.
The other reason for this gap is the fact that the presbyopic patient is one who sometimes didn't need correction before 40. The presbyopes and latent hyperopes who are now beginning to manifest account for the increase in the percentage of the population that needs correction.
The silver lining in this information is that one of the most profitable and rewarding things we do in contact lens practice has a huge potential upside. The gap in the numbers between those who need these lenses and those who wear these lenses is tremendous—and it's at a time when we have more and better presbyopic lens designs available to us.
I have been prescribing contact lenses for presbyopia for nearly 25 years. During that time I have learned a few things that have helped improve my success rate. Most are just common sense; others are not quite so obvious. So, let's review how you can achieve a higher level of success.
More Is Better
The more lens options that we have at our disposal the better, and we have never had more options—both soft and GP (Tables 1 and 2). During the last few years, the industry had created many new lens designs that have greatly enabled us to help more patients than ever before.
In my opinion, the biggest mistake that you can make when prescribing for presbyopia is believing the myth that a single lens design can solve the presbyopic puzzle for all patients. You need to be facile with several lens designs that feature different advantages if you are to be a successful prescriber.
Whether for presbyopes or not, different materials with different dynamics help you achieve comfort and wearability, which are major keys to success. Again, according to the Ciba data from 2009, the major reasons cited by older and younger patients for discontinuing contact lens wear are discomfort and inconvenience; each account for approximately one-quarter of the dropouts. Just because we have a more difficult optics problem to solve doesn't relieve us of our other responsibilities.
However, the optics problem does have a significantly greater impact on our presbyopic patients. The number of patients who drop out of contact lenses because of unacceptable vision doubles after age 40 to one-quarter of all dropouts.
We need different methods of attacking the presbyopic optics problem because our patients perform profoundly different visual tasks, and their brains process multifocal images differently. So, we need lenses that come at the problem from different angles and that, I believe, is the strength of the lenses that we have currently available.
Be an Expert
If you want to be successful at presbyopic prescribing, you have to solve each patient's problems as quickly as possible. As I have written in my column, chair time depletes profitability quite rapidly. Also, repeat visits decrease the patient's perception of the value of the multifocal experience.
You must become an expert at the lenses that you use. The more lenses that you know inside and out, the better you will be at solving the multifocal dilemmas that are unique to each patient.
Choose the Right Patients
One of the most important elements in presbyopic prescribing is determining who is and, just as important, who is not a multifocal lens candidate. Much of what makes for a successful candidate is the patient's ability to tolerate defocus.
One of the best tests that you can use was taught to me by Stan Yamane, OD, FAAO. He would put the patients' manifest distance refraction in the phoropter and take the patients' reading addition in trial lenses. He would have patients look at a far distance and tell them that their manifest was “a 10.” Then, he would hold the trial lenses in front of the phoropter lens wells and say, “That's a zero.” Then he would show patients just the reading lens in front of the right eye, and he would ask the patients to rate their subjective vision, zero-to-10, based on the scale he had just showed them.
He would do the same for the left eye at distance. Then he would repeat the same protocol with the patients looking at a near target, except now the distance manifest was the “zero.” Patients who did not give responses that were “7s” or above did not handle defocus well, and were probably not good candidates for monovision or multifocal prescribing. I have found this simple test to be very good at separating my candidates—especially those dreaded “plano presbyopes.”
Dominance Doesn't Always Equal Preference
One outcome from the “Yamane Test” is that patients sometimes prefer the dominant eye for near. Over the years, I have found the frequency of this preference to be nearly one-in-four. If you want to perform monovision or bias one eye slightly for near or distance, then knowing which eye is preferred at distance is really helpful. When patients prefer their dominant eye at both distances, prescribe for distance in that eye. And don't be afraid to bias a slight amount—especially in older presbyopes.
Get Them While They're Young(ish)
While I am not an advocate for prescribing multifocals for incipient presbyopes who need better light or a little help once in a blue moon, I do think it is easier to train patients to accept multifocal prescriptions if they start with lower reading additions. If you wait until their reading addition is a +2.25D, then they will just have a much more difficult time adapting successfully.
Select the Correct Lens
The correct lens is the lens that gives patients an image that their brains can process efficiently while performing the activities that they do in their day-to-day lives. When prescribing, it is essential to gather as much information about how patients use their eyes as possible. Do they drive all day? Do they read all day? Do they have any special hobbies, etc? You miss 100 percent of the questions you don't ask.
I have found that the lens designs can be biased. For example, because you can put the distance power in the center of both eyes when using the Proclear Multifocal (CooperVision) or Frequency 55 Multifocal (CooperVision), you can bias that system for distance easily. The PureVision Multi-Focal lens (Bausch + Lomb [B+L]) can be biased at near because of the design of the “High” add. The Acuvue Oasys for Presbyopia (Vistakon) and the Air Optix Aqua Multifocal (Ciba) lenses are often successful in the middle of these two extremes.
While I am an advocate of using the prescribing guides—especially for new prescribers—I have found a few tricks that you won't find in the guides that have improved my success. The first tip is that I think the CooperVision lenses should be prescribed with a “D” center on each eye until the patient absolutely cannot achieve acceptable near acuity. Second, don't be afraid to use a “High” add on both eyes when using a B+L, Ciba, or Vistakon multifocal lens. It isn't always successful, but it saves you from time-to-time.
Mix and Match
Don't be afraid to mix and match designs. While the prescribing guides will never tell you that, I will tell you that using one lens design on one eye and another on the other is sometimes the key to success. The point is that you have to be flexible and creative. Multifocal prescribing is not for the mentally rigid who need a cookbook approach to success.
An Add is Not a Microscope
I have “12 commandments” that I give externs rotating through my office, and this rule is one. It is surprising how often you can reduce the add power of a multifocal lens and improve the patient's vision at all distances. I think the prescribing guides sometimes err in advocating near powers that are too strong.
You Have to Have Distance Acuity
Without discussing what constitutes “dynamic visual acuity,” suffice it to say that most distance tasks are at least partially dynamic, they often subtend smaller visual angles, and they often occur in very poor lighting conditions. Driving at night is a good example.
I always concern myself with distance acuity first. I have found over the years that this “20/happy” thing that people talk about is 20/20 or better at distance and 20/30 at near. If I have to sacrifice something, I do it at near most of the time. Many a practitioner has gone astray by sacrificing distance acuity to achieve 20/20 at near. Patients rarely need that level of near acuity.
Also, take patients outside of the examination room. Go outside to demonstrate changes that you're contemplating. Patients don't live in your examination room; they live in the “exam room of life,” and what works in the examination room doesn't always work in the real world—and that can cost you chair time.
Don't be Afraid of the GP Multifocal
You can't call yourself a multifocal expert if you shy away from GP multifocals. I become excited when I see a well-adapted GP lens patient become a presbyope. Prescribing for these patients is easier, in my opinion, because the GP lens provides them with such clear vision that the defocus created by the multifocal optics is not as burdensome.
We have great spline curve lenses that allow us to provide significant reading additions while not creating spectacle blur. Another successful design is the SynergEyes Multifocal lens (SynergEyes); learn to prescribe this lens. I always advocate having diagnostic sets of all of the GP and hybrid multifocal lenses that you use.
Also, remember that you can increase a GP reading addition by using the higher-refractive-index materials. You can change the add by as much as +0.75D by using the same lens design and going to a Fluorex 500 material (GT Laboratories), Paragon HDS HI (Paragon), or Optimum HR (Contamac). Blanchard Contact Lens, which uses Boston materials as its standard material, also makes its designs available in Fluorex 500. It is a real help. The other large laboratories make their lenses available in an array of materials also.
Finally, don't evaluate lens position, segment heights, and rotation with the patient's head behind the slit lamp biomicroscope. You get bad data that can lead you astray. You should use a Burton Lamp.
Do Not Ignore Cylinder
The visual image degradation of the various simultaneous vision multifocal lenses demands that we eliminate the degradation created by uncorrected astigmatism. With the newer multifocal toric designs, there is now no excuse for leaving cylinder uncorrected. My favorite lens in this category is the Proclear Multifocal Toric (CooperVision), but the C•Vue Advanced Toric Multifocal (Unilens) is great as well. The correction of cylinder is also why I like GP multifocals. Now you can obtain some of the GP designs with front toric optics.
Promise What You Deliver
It is very important that potential multifocal patients have a very realistic understanding of what they are getting into. They need to know how challenging the process can be, exactly how much it costs, what the return policies are, what type of vision and comfort that they can expect, and they need to know what their alternatives are. You should tell them that they might require over-spectacles for a specific task if the demand of that task is too specialized.
The better educated your patients are at the start, the less trouble you will have with them down the road. Realistic expectations and no surprises are the path to multifocal Nirvana.
Know When to Say When
Patients want these options. According to the 2009 Ciba study, 6-in-10 presbyopic patients are interested in a contact lens correction, and that number goes up in existing wearers. So, you have to know when to offer them to patients, but you also have to take them away when they are not successful. You have to know when you are defeated. Not everyone that you attempt to prescribe for will be successful. Continuing to chase the impossible is frustrating. It also gets very expensive.
If multifocal prescribing is not profitable for you, then you will lose the will to do it, and that is the biggest barrier we have to prescribing multifocal lenses: resistance on the part of the prescriber.
One sign of failure that I have found over the years is what I call the “break down.” That is when the patient's returning visual acuities are worse than what they were when you dispensed the lenses initially. That is a harbinger of failure.
The other time to know when to say when is when you have reached a successful outcome. Don't make changes with a successful patient. Some patients will continually press you to tweak what they have in search of visual perfection. Don't feel compelled to comply. Nothing takes up more chair time than that. Firmly tell the patient when you have given them the best that you have to offer.
Prescribing for presbyopic patients is rewarding professionally and financially, and as this patient population grows, being an expert at multifocal contact lens prescribing will be a practical necessity. Be willing to invest your time and your treasure in becoming a multifocal lens expert. You won't regret it. CLS
For references, please visit www.clspectrum.com/references.asp and click on document #183.
|Dr. Newman is in private practice in Dallas, Texas, where he specializes in vision rehabilitation through contact lenses, corneal disease management, optometric medicine, and refractive surgery consultation. He is a Diplomate in the AAO Section on Cornea, Contact Lenses, and Refractive Technologies. He is also a consultant or advisor to B+L and Inspire Pharmaceuticals. You can reach him at email@example.com|
Contact Lens Spectrum, Issue: February 2011