Toric Soft Contact Lenses: Where Are We Now?

Optometric Management, Feb 2005 by Hickson-Curran, Sheila, Dias, Louis

Two studies focus on the status of soft toric contact lenses.

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 tories 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.

STUDY #1: 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.

Fitting considerations

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 unconnected astigmatism even though the majority do present soft tories as an option.

Eyecare practitioners most commonly use soft tories 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 tories 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 tories 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 10� 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 5�.

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.

Lessons learned

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.