Retinal Physician Article Submission Guidelines-Prescribing for Astigmatism and Presbyopia

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Article Date: 2/1/2005

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MULTIFOCAL ADVANTAGES
A Shift in Presbyopia Management
A new study compares two methods of managing this common condition.
By Lee E. Rigel, OD, FAAO, Rob Davis, OD, FAAO, John Schachet, OD, FAAO and Paul Klein, OD, FAAO

The emerging presbyope in today's society is markedly different than that of 20 years ago. Many of today's patients are long-time soft lens wearers and expect to continue to experience the comfort and convenience of soft lens wear as their vision needs evolve over time. These same patients are busy, active adults who have high expectations for their vision and low tolerance for discomfort or inconvenience.

Unfortunately, as presbyopia evolves, the surface of the eye becomes dryer. To aggravate this situation, many presbyopes also take medications that have dry eye symptoms as side effects. Meeting the complex needs of this patient demographic presents a challenge that requires attention.

While monovision has been successful in meeting the needs of many presbyopic patients, this solution contains many flaws and isn't the most academic approach for addressing the visual needs of presbyopes. "Monovision has been successful, but is still lacking in a few important areas," says John Schachet, OD, FAAO. This article will look at the multifocal approach to managing presbyopia.

Multifocal Musings

"We have just one eye to meet distance vision needs. With a multifocal lens, we get some near vision from the distance eye and some distance vision for the near eye. That can make a critical difference for a patient," says Dr. Schachet.

Safety is one example he cites. "Let's say a monovision patient is driving down the road with the sunroof down and something flies into his distance lens. He's in real trouble for at least a moment, and that momentary disturbance is just long enough for something bad to happen. With a multifocal lens, at least the patient still has some distance vision from his other eye during that critical moment."

Rob Davis, OD, FAAO, concurs. "Everyone in our practice uses the bifocal design as their lens of choice," he says. "I find that there's just too much separation with monovision. The prescription differences with bifocal lenses aren't as drastic between the eyes, which makes it easier for patients to adapt."

Two Multifocals Go Head to Head

A recent evaluation of two leading multifocal lenses revealed strong success rates and further supports the idea that practitioners and patients no longer view monovision as the standard for managing presbyopic patients. To help practitioners narrow the field of which multifocal lens to reach for first, Foresight Regulatory, with the help of four leading optometrists (Lee E. Rigel, OD, FAAO; Rob Davis, OD, FAAO; John Schachet OD, FAAO; and Paul Klein OD, FAAO) recently conducted a multi-site comparative evaluation of the Frequency 55 Multifocal (CooperVision) and the SofLens Multifocal (Bausch & Lomb).

The randomized, open-label, two-week dispensing crossover study compared distance and near visual acuity, ocular physiology, fitting ease, subjective comfort when worn for daily wear and overall success. None of the evaluators knew of the sponsor (CooperVision) and the patients had no previous experience with either contact lens brand.

Investigators completed study evaluations for each subject at the initial/dispensing visit, one-week and two-week visits and at 48- to 72-hour post-dispensing fitting evaluations for each of the two lens brands. If the subject couldn't achieve a good fit with the first pair of lenses, then an investigator trial fit and dispensed a second pair. If the subject couldn't be fit with either the first or the second brand of lenses, then he was discontinued from the study.

Study Specifics

This study evaluated the qualitative and quantitative aspects of the two multifocal lens brands mentioned above. Four investigators from geographically diverse sites recruited 60 presbyopic subjects who had normal eyes and were generally successful soft contact lens wearers for the study. In all, 51 subjects completed the study, three exited during enrollment and six discontinued during the evaluation.

Of the 60 subjects recruited for the evaluation, 11 were male and 49 were female, all ranging in age from from 43 to 71, with an average age of 52.2 years. Overall, these were experienced contact lens wearers, with an average of 17.7 years of contact lens wearing experience (Figure 1). An average pupil size of 4.17mm was reported with a range of 2mm to 6mm.

Investigators randomly trial fit each subject with one of the multifocal lens brands. They dispensed the lenses to subjects at the initial/dispensing visit and evaluated them again after 48 to 72 hours to assess lens fit, vision and comfort. The investigators scheduled follow-up visits six to nine days after the initial fitting and evaluation and collected quantitative data to measure visual acuity and ocular physiology. Additionally, subjects answered a series of qualitative questions about the lenses. Subjects went through the same process for the second (randomly chosen) brand of lenses.

Figure 1. Length of time the 60 subjects had worn lenses.

Results and Discussion

While both lenses performed well in this study, clinical investigators identified many characteristics of Balanced Progressive Technology (Frequency 55 Multifocal) that provide an advantage in managing presbyopia, particularly in regard to the range of add powers available and the flexibility of the lens design while fine-tuning the fit. Dr. Rigel said, "The fitting system of the Frequency 55 Multifocal is simple and straightforward. Perhaps the best feature of this lens is that the practitioner can make small incremental changes in vision." He continued, "We tend to like this because this option provides control of the direction of the fit and with minor tweaks, adjustments and modifications, we can enhance and improve our patients' fits."

The simplicity of the Frequency 55 Multifocal fitting system mainly results in the large number of lens parameters available (+4.00D to �6.00D spheres in 0.25D steps, with each sphere power available in four add powers and either a "distance" or "near" design). Therefore, for each sphere power, the Frequency 55 Multifocal effectively has four times as many power designs compared to the SofLens Multifocal. For example, for a �3.00D sphere power, the Frequency 55 Multifocal has +1.00D, +1.50D, +2.00D and +2.50D adds with each available in a "D" or "N" add. By way of comparison, the SofLens Multifocal has only a "low" and a "high" add in the �3.00D sphere power.

Snellen distance acuity was similar between the two lens brands. However, when compared by eye and binocularly, Jaeger near visual acuity was better with the Frequency 55 Multifocal lens. A by-eye comparison revealed that 60.2 percent obtained J2 or better with the Frequency 55 Multifocal, vs. 48 percent with the SofLens Multifocal. Binocular near visual acuity with the Frequency 55 Multifocal lenses was J2 or better in 79.6 percent of the subjects as compared to 74 percent of the SofLens wearers.

Patient questionnaires further demonstrated a preference for the Frequency 55 Multifocal when attempting close-up tasks such as makeup application and reading a watch (Figure 2). "We shouldn't overlook the slightly better performance of the Frequency 55 Multifocal lens in near visual acuity," stated Dr. Rigel. "After all, most emerging presbyopes come into our practices complaining of difficulty with near vision. Our challenge is to always improve near vision without degrading the excellent distance vision to which our emerging presbyopic patients are accustomed."

The stereopsis with the Frequency 55 Multifocal's Balanced Progressive Technology is better (lower value) at both baseline and at follow up (61.3 and 54, respectively) compared to the baseline and follow-up values of the SofLens (67.2 and 83, respectively). With a measurement of 54 seconds of arc, the Frequency 55 Multifocal is much closer to the ideal stereopsis measurement of 40 seconds of arc, as compared to the SofLens measurement of 88 seconds of arc.

"The Frequency 55 Multifocal lens provides advantages in stereopsis and contrast sensitivity," reported Dr. Rigel. "This lens is also excellent for monovision wearers who are reaching a point where too much disparity exists between near and distance vision. The full range of vision from the Frequency 55 Multifocal lens makes this lens an excellent solution to a common problem."

Subjects successfully fit quickly adapted to the test lenses and as many as 86.2 percent of subjects wore their contact lenses seven days each week, many for as long as 19 hours each day. Comfort is critical to successfully supporting these wearing schedules. The aggregate questionnaire responses related to "overall comfort" demonstrated a preference for the CooperVision Frequency 55 Multifocal lens by a small margin.

Figure 2. Patient evaluation of near vision in a variety of tasks.

A Clear Preference

Practitioners and patients welcome a multifocal lens that can provide ease of fit, comfort and a range of crisp visual acuities. The clinical evaluation previously summarized reveals that while the visual performance between the two lenses was comparable in terms of distance vision, the Frequency 55 Multifocal provided better near vision when compared to the SofLens Multifocal as demonstrated by the Jaeger visual acuity measurements and supported by the questionnaire responses.

Further, the Frequency 55 Multifocal provided superior stereopsis as compared to the SofLens Multifocal. Also, a key advantage reported was the availability of the Frequency 55 Multifocal in a wider range of add powers and the flexibility of its design and fitting system as far as fine tuning the final fit.

In the course of this evaluation, certain advantages came to light with regard to the Balanced Progressive Technology in the Frequency 55 Multifocal lens. "Of all the lenses on the market, the Frequency 55 Multifocal is my initial lens of choice," said Dr. Davis. "I have opportunities with this lens to fit patients I couldn't help with other designs. The wide range of add powers, combined with a fitting system that allows me to address each eye independently, gives me the flexibility to meet my patients' needs that I just can't find anywhere else."

"Academically speaking, the core advantage of the Frequency 55 Multifocal is the flexible design with a distance-sighted lens and a near-sighted lens," said Dr. Davis. "Initially, I fit a D lens on the dominant eye and the N center lens for the nondominant eye. But if I wish to further refine acuity in a small percentage of my patients, I do have the option to mix two D or two N lenses, which is something unique to the Frequency 55 Multifocal lens. I have the flexibility to tailor the design to the individual needs of my patients."

This multi-center clinical evaluation revealed that the Frequency 55 Multifocal's extensive range of add powers is attractive to practitioners and is therefore an advantage over the SofLens Multifocal system, which offers only a "low add" and a "high add" profile. Said Dr. Schachet, "There's an advantage with the Balance Progressive Technology. Multiple add powers and different N and D lenses allow me to tailor near and distance vision while keeping the core prescription the same. A nice advantage over the SofLens Multifocal is its superior performance for patients who have higher add powers," he continued. "Now we don't have a concern when the patient comes in two years later needing additional correction. We can keep him in the same lens and just change the add power. This design keeps me from wasting my valuable chair time, and I don't have to start over every time a patient comes in."

Excellent Design, Enhanced Material

Recent enhancements to the lens material have integrated the lens dryness and discomfort combative material of CooperVision's Proclear line of contact lenses (omafilcon A, 62 percent water content). Given the tendency of the presbyopic patient demographic to experience dry eye symptoms, practitioners are eager to finally have the technology of the Proclear material together with the Balanced Progressive Technology design of the Frequency 55 Multifocal. "My nonpresbyopic Proclear wearing patients love this material," said Dr. Schachet. "I'm excited to be able to offer the Balanced Progressive Technology design in the Proclear material. Now I'm confident that patients who were already successful in the Frequency 55 Multifocal design will become even more successful with the comfort enhancements of the Proclear material."

Embrace the Best Presbyopic Option

Multifocal lenses are swiftly emerging as a lens of choice for managing presbyopia. Results from this evaluation, together with anecdotal experience from our respective practices, point to new support for the Balanced Progressive Technology available in both the Frequency 55 Multifocal and the Proclear Multifocal as the multifocal lens of choice for all presbyopic patients from emerging to advanced.

One thing is certainly clear: New materials and wider options are paving the way for happy patients with longer lens-wearing cycles. The time has come to raise the bar, abandon monovision and provide our patients with the binocular and full range of vision that they deserve.

Dr. Rigel is a fellow of the American Academy of Optometry and is a diplomate of the Academy's Cornea and Contact Lens Section. He's also presently chairman of the Foresight Optometric Meeting and the American Society of Corneal Refractive Technologies.

Dr. Davis has worked extensively in the management of eye care for more than 20 years. He has developed many contact lens designs and is a Fellow and Diplomate in the American Academy of Optometry.

Dr. Schachet has a large, private contact lens practice in Englewood, CO, where he specializes in dry eye, allergy and CRT.

Dr. Klein is in private group practice specializing in contact lens care, therapeutic optometry and laser vision correction in Fort Lauderdale, FL. He's also an adjunct professor of optometry at the Pennsylvania College of Optometry and has published and lectured internationally.

 


Contact Lens Spectrum, Issue: February 2005

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