While the monovision-versus-multifocal debate for presbyopia continues (which is the better Rx for vision correction?), todays patients over the age of 40 have even more contact lens options to choose from than ever before. Recent additions to the market include a contact lens that targets early presbyopes, a hybrid lens with a gas-permeable center surrounded by a soft lens skirt and the first silicone hydrogel multifocal.
We have so many new patients each year entering into the presbyopic category. Just when we thought there was nothing new, along comes some exciting designs in additional materials, says Joseph P. Shovlin, O.D., of Scranton, Pa. Eye-care professionals should be less timid in recommending bifocal or multifocal lenses today; fortunately, we have a wide array from which to choose.
Which is Better: Monovision Or Multifocal?
When deciding on a contact lens for your presbyopic patients, you first need to decide whether monovision or multifocal is the best approach.
The advantages that monovision provides over multifocals include uninterrupted visual acuity in each eye and less chair time than bifocal and multifocal contact lens fittings. Monovision may be especially helpful for fitting hyperopic patients, astigmats, or younger presbyopes.
Fitting Pearls for Multifocal and Bifocal Contact Lenses
Options are important. If you provide a wide lens selection to your patients, 70% of them should be able to wear basic bifocal lenses, says Birmingham, Ala., optometrist Jack Schaeffer, immediate past chair of the AOA Contact Lens and Cornea Section.
Dont be afraid to use different products with different eyes. Difficult patients may need different types of lenses on their right and left eye, Dr. Schaeffer says.
Doctors need to realize that, in todays market, monovision is a compromise in vision, says Dr. Schaeffer. Optometrists must consider night vision issues that patients may have. Night driving is a problem with monovision. If a patient drives at night, they should be thinking about bifocals. This helps not only the patient, but the other drivers on the road as well, he adds.
Gas-permeable bifocals will give patients the best vision on the market, Dr. Schaeffer says. In addition, there are multiple options to choose from in this category. The average bifocal patient takes a minimum of three visits to complete the evaluation and fitting.
However, some optometrists feel that monovision compromises a patients vision, since it weakens the efficacy of binocular vision. A recent study found that patients prefer multifocal contacts to monovision by a ratio of approximately three to one.1 In a crossover study of 38 patients with presbyopia, patients were randomized into two groups: each wore either multifocal or monovision lenses for one month. Of the total cohort, 76% of patients in the study reported that they preferred multifocal contact lenses, while 24% preferred monovision contact lenses. The study attributed these findings to the excellent visual acuity the multifocal lens provided without compromising stereo acuity to the same degree as monovision.
Whats New in Contact Lenses
Whether they are soft, gas permeable, bifocals, or multifocal lenses, optometrists should keep multiple lenses in stock in order to evaluate their presbyopic patients properly. There isnt just one lens for everyone anymore, says optometrist Jack Schaeffer, of Birmingham, Ala., immediate past chair of the American Optometric Association Contact Lens and Cornea Section. Keep a steady stock of multiple soft lens and rigid lens designs, including soft annular, aspheric and concentric designs, as well as rigid aspheric and translating designs.
Here is a snapshot on some of the latest products for your patients over 40:
Biomedics EP. From CooperVision, this is the only contact lens designed for emerging presbyopes currently on the market. These two-week disposable lenses are designed for patients with an add less than +1.50D. Biomedics EP (EP stands for early presbyopes.) feature sphere powers of +4.00D to -6.00D in 0.25D steps, an 8.7mm base curve and a 14.4mm diameter. They are made from omafilcon A and have a water content of 60%.
This is a great lens for that hyperopic patient who is now an emerging presbyope, Dr. Shovlin says. The lens has a center spherical distance zone with a progressive aspheric zone for inter- mediate and near vision.
Soft Toric Multifocal Clinical and Practice Management Pearls
By Jason R. Miller, O.D., M.B.A.
Success with soft toric multifocal lenses begins with a solid refraction.
Set expectations up-front.
Discuss projected fees.
Set a clear time frame for adjustment to the new lenses.
Discuss visual expectations.
Discuss the need for follow-up care.
Use similar strategies with soft toric multifocal contact lenses as with traditional soft multifocal lenses, but allow for rotation of the lens.
Be flexible and confident with your doctor-patient discussions.
Develop a starting-point strategy.
I have found the lens very useful for patients looking to get a little more out of their monovision contact lenses, says Jason R. Miller, O.D., M.B.A., of Powell, Ohio. I start with same Rx as their monovision lenses, and I have found that the patient has a slightly larger range of clear vision.
Optometrist Brian Chou of San Diego, Calif., uses the Biomedics EP for presbyopes who require up to a +1.25D near add power. He has found that this lens works well in cases of incipient presbyopia by improving near vision without noticeably sacrificing distance vision. The Biomedics EP lens also requires minimal chair time to prescribe, so it is helpful in satisfying those patients complaining of near vision difficulty and who are unwilling to spend great amounts of time or money in being fit with presbyopic lenses, he adds.
The doctor prescribing Biomedics EP usually has a minimal time burden, to the extent that progress visits and fees for additional time are not necessary, Dr. Chou says. The caveat, however, is to let these patients know that as their presbyopia advances (near add requirement increases beyond +1.50D), they will likely require refitting into a different multifocal lens design, where additional time and related professional fees are expected.
SynergEyes Multifocal. This hybrid design aims to eliminate the instability and soft optics issues associated with other multifocal contact lenses. From my vantage point, having worked with this lens for the past 18 months, its design has tremendous utility in clinical practice, says Dr. Shovlin. It has all the benefits of both a soft and rigid lens wrapped into one.
Case Report: Single Vision Soft Toric to Multifocal Soft Toric Contact Lenses
By Jason R. Miller, O.D., M.B.A.
A 51-year-old female who wears single-vision soft toric contact lenses presented to my office complaining of blurred vision both distance and near. She was not only having trouble seeing the ticker on the bottom of the television, but she was also complaining of difficulty focusing while she was on her computer or reading smaller print. She had no complaints of dry eyes or discomfort with her current contact lenses. The current lenses were slightly under-corrected O.U.
Her best-corrected visual acuity was 20/20 O.U. with a manifest refraction of -6.00D-1.50Dx026 O.D. and -4.75D-1.75Dx174 O.S. The patient also had a +1.75D add O.U. External and internal ocular health examinations were clear and quiet in both eyes.
Management and Discussion
At this point, we held a doctor-patient conference. I believe that it is important to identify the patients occupation, hobbies and daily visual requirements. I also preface the contact-lens fitting by describing how lens technology has advanced greatly in the multifocal arena in the past few years. Additionally, I discuss how these lenses allow patients to have clear distance and near vision for the vast majority of visual tasks. For example, fine print, such as that on a pill bottle, may still require the use of low-power readers. Also, glasses may play a role when patients eyes are tired, or when patients read for an extended amount of time, so an up-to-date glasses prescription is important as well.
This patient desired better near vision without sacrificing any distance vision. In fact, she wanted improved distance vision. Many of us have already experienced similar challenging situations. Many O.D.s may suggest switching to full-time spectacles, monovision contact lenses, or going to distance contacts with over-readers. I recommend multifocal contact lenses because I believe that they provide the most flexibility. I may have to modify them to meet a patients needs, but I use the other options as alternatives.
After experience with these multifocal contact lenses, confidence and comfort levels will increase over time. I have a specific formula I usually start with: Use the low add lens or distance/dominant lens (D lens), depending on the brand. I use the appropriate add power (but nothing over a +1.50D add) and a +0.50D under-correction in the non-dominant eye (which I determine with a +2.00D fog while in the phoropter).
I spend little time letting the lenses settle in-office. In the beginning, my job is primarily to encourage the patient to wear the lenses as much as possible to help their eyes adjust. We schedule a follow-up appointment in one week. I have had noticeably lower success rates with higher-powered add lenses and near dominant lenses (N lens), so I reserve those lenses for troubleshooting.
We opted to special order the Proclear Multifocal Toric (CooperVision) contact lenses. I ordered a -5.50D-1.25Dx020 D lens with a +1.50D add for the right eye and a -4.25D-1.25Dx170 D lens with a +1.50D add for the left eye. Upon insertion, her distance acuity was 20/20 O.U., and her near acuity was 20/25 O.U. The lenses were perfectly centered.
During the follow-up exam one week later, only one minor axis adjustment of 10 was necessary in the left eye. Her distance visual acuity was 20/20 both O.D. and O.S., and 20/20+ O.U. Her near visual acuity was 20/30 both O.D. and O.S., and 20/25 O.U. Her binocularity has not been compromised, and her visual needs were met and exceeded.
The lens has a rigid gas-permeable center and a soft contact lens skirt. The irregularities of the front surface of the eye that are usually transferred to the front surface of a soft contact lens are neutralized by the eyes tear film and the gas-permeable center.
Company officials say that the new multifocal lens also provides good centration and stability. The reading portion is small: 1.9mm or 2.2mm. Three reading powers are currently available in 0.50D steps ranging from +1.25D to +2.25D. It has a diameter of 14.5mm and a wide range of distance power.
The SynergEyes Multifocal is an excellent lens choice for presbyopic contact lens correction, including patients with low-to-moderate corneal astigmatism, Dr. Chou says. It does not have the initial lens edge awareness of a rigid lens due to its soft skirt. And, unlike a soft toric multifocal, the turnaround time with the SynergEyes multifocal is quickusually just one to two days within a core parameter range, he adds. By comparison, most soft multifocal torics take at least a few weeks.
The patients I"ve prescribed SynergEyes Multifocal for have generally found that this lens offers excellent comfort and vision. Lens removal does seem to require a little more work, especially in the beginning, says Dr. Chou. Since its a unique contact lens, patients seem to instinctively value how practitioner services are required for the lens to provide optimal performance.
PureVision Multi-Focal. From Bausch & Lomb, the PureVision Multi-Focal contact lens is the first silicone hydrogel multifocal on the market. The PureVision Multi-Focal combines the companys balafilcon A and AerGel silicone hydrogel materials and a patented rounded-edge design, which helps reduce lens awareness. This multifocal is a wonderful design just made better by making it into silicone hydrogel material, Dr. Shovlin says. Patients will easily adapt to this design.
It comes in an 8.6mm base curve, 14.0mm diameter and in powers ranging from +6.00D to -10.00D in 0.25D steps. The PureVision Multi-Focal is indicated for daily or extended wear (up to 30 days) and should be replaced monthly.
Proclear Multifocal Toric. CooperVision recently extended the parameters of the Proclear Multifocal Toric. Now, it is available in a sphere power range of +20.00D to -20.00D in steps of 0.50D after +/- 6.50D.
Proclear Multifocal Toric lenses have cylinder powers of -0.75D to -5.75D in 0.50D steps, axes in 5 steps, and add powers of +1.00D to +4.00D in 0.50D steps. They also feature two base curves: 8.4mm and 8.8mm. Proclear Multifocal Toric lenses are manufactured with omafilcon A, which has high affinity for water. Also, this material creates a shield of water on the lens surface to prevent deposits from adhering to it and allows the lens to resist dehydration. This is the only multifocal toric contact lens available in a monthly modality.
CooperVision provides a wide range of options in correcting that patient with cylinder needs, Dr. Shovlin says. Ive been pleasantly surprised by our results. Admittedly, I went into using it as a skeptic.
Also, he adds, Dont be afraid to mix and match various designs, especially since most of the designs that are available today favor either better distance or near performance [instead of both].
What"s nice is that for patients needing a toric lens in only one eye, I can keep him or her in the same monthly replacement schedule and same lens material, he adds.
CIBASOFT Progressive Toric. This lens, by CIBA Vision, features a double slab-off, front-surface toric design combined with a center-near progressive add on the back surface. The lens is made of tefilcon, a non-ionic material that has a 37.5% water content. It comes in a 14.5mm diameter, 8.6mm and 8.9mm base curves, a power range of +9.00D to -9.00D, cylinders of -0.75D to -2.75D in 0.25D steps, and around-the-clock axes in 5 increments. A zero-cylinder is available for patients who require astigmatic correction in one eye only. CIBA Vision recommends a six-month to annual replacement schedule.
So, what does the future hold regarding new contact lenses for your presbyopic patients? In the near future, our industry can expect more silicone hydrogel multifocalsbut, while they may offer better comfort and reduced hypoxia, its unlikely that theyll offer significant vision improvements over their hydrogel counterparts, Dr. Chou says.
Or, perhaps being overly optimistic about the future, as good as the designs are, theyll only get better, Dr. Shovlin counters. I look forward to better correction of the aberrations that plague the visual system and, by doing so, [we] can only enhance the overall performance of a wide variety of possible lens designs.
Richdale K, Mitchell GLM, Zadnik K. Comparison of multifocal and monovision soft contact lens corrections in patients with low-astigmatic presbyopia. Optom Vis Sci 2006 May;83(5):266-73.
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