soft toric lenses
Toric Soft Contact Lenses: Where Are We Now?
Two studies focus on the status of
soft toric contact lenses.
BY SHEILA HICKSON-CURRAN, B.Sc., MCOptom, F.A.A.O. & LOUIS DIAS, B.Sc., Jacksonville, Fla.
Soft toric contact lenses have become an increasingly viable and popular fitting option thanks to improvements in lens designs and manufacturing as well as the introduction of frequent replacement and planned replacement lenses. But despite this modality's improving status, contact lens practitioners still widely view soft torics as complex, time-consuming and expensive. Additionally, the proportion of soft toric lenses fit fails to reflect the incidence of astigmatism among contact lens wearers.
To make the fitting process simpler, faster and more cost-effective, it's important to understand current habits and practices in soft toric fitting. And to understand what astigmatic patients really want from their contact lens correction, we need to evaluate patient satisfaction with currently available lenses. We conducted two studies to investigate the current status of soft toric lenses and to try to determine the reasons why these lenses have yet to meet their full potential. This article will review the results of those studies.
Fitting habits and practices
We conducted online interviews with 153 eyecare professionals (qualified optometrists and ophthalmologists who prescribe soft toric lenses) across the United States to gain a better understanding of their practices, expectations and requirements with respect to fitting soft toric lenses.
Our survey found that contact lens practitioners most commonly prescribe soft toric lenses at 1.00DC of astigmatism and above (Figure 1). Eyecare practitioners use spherical lenses mostly for cylinder powers of 0.25DC and 0.50DC. They don't widely use GP lenses, with only one in four eyecare practitioners prescribing this modality.
Many studies have found that practitioner recommendation is a key factor in the uptake of contact lenses. In this study, we found that only half of eyecare practitioners proactively recommend soft toric lenses to their astigmatic patients for previously uncorrected astigmatism even though the majority do present soft torics as an option.
Eyecare practitioners most commonly use soft torics because they feel that they provide the best vision and optical quality, are more comfortable for patients and are easier to fit with available diagnostics. Among the most important secondary considerations when choosing to fit soft torics are the replacement schedule and the patient's specific visual demands.
Soft toric success factors
The number of trial fitting and follow-up visits has important implications for appointment scheduling and pricing and may play a role in practitioners' perceptions of soft torics and their willingness to fit them. (A lens that fits rapidly and works most every time would permit shorter fitting appointments and less follow-up visits. In such a situation, practitioners may become confident enough with the lens performance to fit and order lenses without asking subjects to return to the clinic after a trial-wearing period.)
Ultimately, more successful, simpler toric lenses would reduce fitting time for both patients and practitioners and may eventually bring toric fitting fees in line with those of spherical soft lenses. Practitioners report that one to two trial visits and the same number of follow-up visits are needed to successfully fit a soft toric.
Lens rotation is a key measure of successful soft toric fitting. Lens rotation of 10º or less is generally considered the maximum for acceptable fit. According to the results of our online interviews, at 1.75DC, fewer than half of eyecare practitioners are satisfied with lens rotation greater than 5º.
Eyecare practitioners successfully fit only eight out of 10 patients using their lens of choice.
Making your first lens choice
When selecting a lens brand of first choice, the ability to fit patients successfully is the primary factor eyecare practitioners consider, followed by comfort, vision and ease of handling. On average, they would try a new brand on 10 patients before deciding to fit that lens regularly, although around one in three would base their decision on five or fewer patients. The minimum success rate eyecare practitioners would consider before a new brand becomes their lens of choice is about 66%.
One to two-week disposable lenses for daily wear and monthly replacement for daily wear are the most preferred and regularly fitted soft toric lens modalities, according to our interview results.
The findings of this first study confirm the wide range of approaches that eyecare practitioners currently take to fit soft toric lenses and we can use these approaches to develop and improve fitting processes and management strategies.
Through our interviews, we've found that eyecare practitioners believe that soft toric contact lenses are the best option for meeting the needs of their astigmatic patients, but fitting soft toric lenses still remains challenging. There is an opportunity to increase eyecare practitioner satisfaction in fitting soft toric lenses with a faster fitting, more stable lens.
To understand what astigmatic patients really want from their contact lens correction, we conducted a second study in which we surveyed 335 astigmats at 19 sites across the United States about their attitudes toward their current lenses and toward contact lenses in general. Patients were existing daily wear soft lens users (85% currently wearing a soft toric) with 0.75 to 2.50DC of astigmatism and were chosen to represent a cross-section of the population with respect to age, previous lens use and current lens brand. The study consisted of an initial baseline visit, fitting visit, two-week wearing trial and follow-up visit.
At the initial visit to the study site, patients completed a questionnaire regarding the factors important to them in the performance of contact lenses and their opinions of their current lenses. To optimize clinical performance, they were then fit with one of four soft toric contact lens brands (Vistakon's Acuvue Toric [n = 86], Bausch & Lomb's SofLens 66 Toric [n = 86], Ocular Sciences' Biomedics Toric [n = 77] and CooperVision's CV Encore Toric [n = 86]) under study conditions.
We asked those patients who were dispensed lenses to return after two weeks to complete a questionnaire assessing their satisfaction with the study lenses.
Expectations and opinions
Figure 2 illustrates the patient opinions regarding the importance of lens attributes to toric contact lens performance. Patients cited vision- and comfort-related factors as having the highest importance.
The subjects' habitual contact lenses were broadly representative of the U.S. market and were rated consistently lower than their expectations of contact lenses (Figure 3). Only 70% of the patients surveyed described their overall opinion of their lenses as "excellent" or "very good" and ratings for aspects of vision and comfort, the factors they considered most important to contact lens performance, also fell short of expectations. Only 74% rated overall quality of vision and 65% described overall comfort with their current contact lens as "excellent" or "very good." Among the symptoms reported, 86% said they experienced blurred vision with their current lenses and 57% reported fluctuating vision.
Satisfaction ratings at two weeks (when subjects returned wearing the toric lenses prescribed to them in the study) were consistently lower than patients' expectations of contact lenses (Figure 4). Only 58% rated overall satisfaction as "excellent" or "very good" and ratings for aspects of vision and comfort again revealed gaps in performance.
Mean visual acuity was nearly one line (0.07 logMAR) poorer than spectacle visual acuity and only 70% of patients rated overall quality of vision as "excellent" or "very good." Only 54% said that the statement "They were comfortable to wear all day long" described the lenses "completely" or "very well" and only 68% of patients rated overall comfort as "excellent" or "very good."
Asked how well the study contact lenses met expectations, patients' opinions were divided (Figure 5). Less than half (48%) of the respondents said that the contact lenses were "much better" or "slightly better" than expected and in 25% of cases, the contact lenses failed to meet expectations ("much worse" or "slightly worse").
This study has confirmed that astigmatic patients have high expectations of their contact lenses, particularly with regard to vision and comfort. Patients' satisfaction with their current lenses was consistently rated low in comparison with their rating of the importance of various attributes to contact lens performance and the characteristics they considered important when deciding which brand of soft toric lenses to buy.
Comparing these findings with those of our previous study, we found that good vision and comfort, the features that astigmatic patients consider most important to contact lens performance, are also the principal reasons why practitioners prescribe soft toric contact lenses and are among the deciding factors when selecting a lens brand of first choice.
Where do we go from here?
The number of patients who could benefit from soft toric contact lenses is still vastly greater than those who are prescribed and who successfully wear currently available products, and the unmet eyecare practitioner and patient needs that these two surveys highlight suggest reasons for this fact.
If manufacturers provide a contact lens that better meets the needs of eyecare practitioners and satisfies patients' expectations, then everyone will benefit. A faster fitting, more stable lens that delivers expectations of excellent comfort and vision will close the gap between these expectations and the soft toric contact lenses that are currently available.
We should judge new soft toric contact lenses that enter the market in 2005 on their ability to address the need for improved vision, comfort and ease of fit in the category.
Dr. Hickson-Curran is principal research optometrist at Vistakon, Division of Johnson & Johnson Vision Care, Inc. She has a special interest in contact lens design and correction of astigmatism and has been issued patents and has authored papers and book chapters on these topics.
Louis Dias is worldwide director of New Products Marketing Research at Vistakon. He has a special interest in customer-centric product development and has been involved in multiple new product launches in different categories.
Optometric Management, Issue: February 2005