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Assessing a New GP Lens Family

readers' forum
Assessing a New GP Lens Family

As optometric physicians in private practice in a northwestern college community, we're always looking for contact lens options that will meet our patients' needs for excellent visual acuity, eye health, durability and wearability. As small businessmen, we're constantly looking for lens modalities that will meet those patient needs and help our practice maintain its profitability. At the same time, we look for lenses that will allow easy adaptation, varying oxygen permeability for different applications, convenient care regimens and day-long "on-eye" comfort.

Last year, we studied a new family of lens materials (Optimum, Contamac Ltd, Essex, UK, Table 1) designed to meet those needs. This article describes our informal, 100-day investigation involving our clinic, Youngs Valley Contax (a national contact lens fabricator) and Contamac USA, Inc.

Proposing an Investigation

In February 2004, Stephen Young, owner of Youngs Valley Contax of Springfield, OR, approached us to see if we had any interest in conducting an "informal" study of Contamac's new Optimum family of GP materials. Contamac had introduced the materials into the United States in January 2004 after extensive clinical trials outside of the United States.

Contamac had approached Mr. Young and asked him to distribute its new materials. Mr. Young and Valley Contax have always prided themselves on the quality, performance and reproducibility of their GP products and have avoided endorsing any particular product. After touring the Contamac facility, Mr. Young wanted to find out whether this new range of lenses was as good as it seemed. He contacted us and we began to develop this study.

We held several meetings to determine how to design a program to review the new materials. Because we're not a large, multi-doctor office, we never intended to conduct a technical scientific investigation. Our goal was to determine whether the new materials provided a noticeable improvement for our patients.

Beginning the Process

We sent a letter to all of our GP wearers, offering them a complimentary pair of "new" lenses. In return, we required them to return for a one-week and a one-month post-dispensing visit. At the one-month visit, we required them to return their new lenses (so that Valley Contax could perform a physical inspection) and to answer a brief survey about their wearing experience with the new lenses.

If participants hadn't received an exam within the last year, then we required them to undergo a current evaluation of their cor-neal health, topography, refractive error and lens fit. We imposed no restrictions on age, gender, occupations or lifestyle.

One-hundred-and-five individuals who had normal eyes volunteered to participate in the investigation. Of these, 103 patients had worn fluorosilicone or silicone acrylate GP lenses previously and had used either a two-bottle or a multipurpose solution regimen.

Most of the subjects had previously worn Boston ES or Fluoroperm 30 (Paragon Vision Sciences) materials. Other materials included Boston EO and Boston XO (Bausch & Lomb), Fluoroperm 60 (Paragon) and Fluorex 700 (G.T. Laboratories).

If patients didn't require fit changes, then we provided them with new lenses in the same parameters as their current lenses. If they required fit changes, then we supplied the changes in the new materials. In the case of some multifocal wearers, we changed lens designs to comply with availability (the Solitaire II design is not yet available in the Optimum material). Contamac recommends Optimum by Lobob solutions (Table 2) for its new materials, so we required patients to switch to Optimum by Lobob solutions if they weren't currently using them.

 TABLE 1 The Optimum Lens Family



26 12 degrees
Comfort 65  6 degrees
Extra 100 3 degrees
Extreme 125 6 degrees

Conducting the Study

We initially intended to designate which of the four materials from the Optimum family of lenses we would give to each patient. But after further discussion, we concluded that our assessment might be less biased if we didn't know what material individual participants had received. We felt comfortable that all four materials had undergone thorough testing through clinical trials and that any of the Optimum materials would serve our patients' needs for the short term. However, when we felt strongly that a specific material was more appropriate for a specific patient, we indicated which material to supply.

In a majority of patients, we didn't know which material they had received. A few patients received a different material for each eye. We left those determinations to Valley Contax.

We told patients that their "new" lenses might even be a new pair from their habitual material and that we wouldn't disclose which materials they'd received until the study concluded. We held their habitual lenses in quarantine to ensure that patients wouldn't "mix" the lenses. We returned patients' habitual lenses at the conclusion of the study. If a subject preferred his old lenses to the study lenses, then we gave him a new pair in his habitual material.

Of the sample, we fit 20 percent of eyes with Optimum Classic, 30 percent with Optimum Comfort, 27 percent with Optimum Extra and 23 percent with Optimum Extreme.


TABLE 2 Optimum by Lobob Solutions


  • Optimum Wetting and Rewetting Solution

  • Optimum Cleaning, Disinfecting and Storage Solution

  • Optimum Extra Strength Cleaner Solution


Forty-five percent of the subjects returned their surveys. All of the respondents had received Optimum materials. Of these, 32 percent agreed with the statement, "These lenses feel very comfortable." Ten percent of those responding said the lenses were an improvement over their habitual lenses during the allergy season. Eighty-two percent rated overall lens comfort as either "very good" or "excellent." When asked whether they were "able to wear their lenses as long as they would like each day," 90 percent said "yes." Seventy percent said that end-of-day comfort was either "excellent" or "very good."

When asked to consider all of the aspects of the study, 90 percent said that the study lenses were "as good as" or "better than" their habitual lenses, 39 percent said the study lenses were "somewhat better" and 30 percent said that the study lenses were "much better" than their habitual lenses. Only five participants wanted to return to wearing their old lenses.

While 55 percent of respondents said they preferred the Optimum lens care solutions, Dr. Knutson's own experience as a long-time GP wearer confirmed Contamac's recommendation that the Optimum materials perform better in conjunction with Optimum by Lobob solutions.


When Mr. Young first approached us with this study concept, we were excited about the possibilities that a combination high-Dk and lower-wetting-angle (determined by dynamic contact receding angle) material could bring to our practice. In this informal study, it became clear to us that the Optimum family of lenses is highly wettable and comfortable.

The higher Dk and low wetting angle of the Optimum Comfort, Extra and Extreme materials enabled us to deliver to our patients increased quality of vision and longer wearing time without compromising comfort and corneal health. The Dk range allows us to fit patients who have a variety of refractive errors as well as varying lifestyles and wearing demands. The durability and stability of the material appealed to us as well.

It's our impression that the Optimum family of GP contact lenses, worn in combination with the Optimum by Lobob system of solutions, is an important step forward in the GP arena and will help us continue to provide our patients with quality eyecare products in this highly competitive marketplace.

Drs. Knutson and Young are in private practice in Corvallis, OR. Mr. Young is the owner of Youngs Valley Contax, a contact lens fabricator in Springfield, OR.