SILICONE HYDROGELS

Making the Move to Silicone Hydrogels

A look at the benefits of these lenses and how to better incorporate them into your practice.

By Timothy Giles, OD, MBA, FBCLA, FIACLE; Anne Austin Thompson, MS, OD; S. Barry Eiden, OD, FAAO; & Kelly Kerksick, OD

Dr. Giles is the global director of Professional Education for Ciba Vision's Professional Affairs Department Dr. Thompson is director of Professional Programs at Visual Eyes, Inc. Dr. Eiden is president and medical director – North Suburban Vision Consultants, Ltd. Dr. Kerksick is the director of Professional Services for Vision Source.

We tend to be creatures of habit. Subject to Newton's Law of Inertia, we can get comfortable doing things a certain way, making it harder to embrace new ideas even when there are compelling reasons to change.

Case in point: silicone hydrogel (SiHy) lenses have been available commercially for more than a decade. They represent a remarkable innovation in contact lens technology and offer important advantages over HEMA lenses—yet many practitioners continue to fit and refit patients in the older lens materials and designs.

A decade of clinical experience has shown SiHy lens wear to be safe and successful (Bergenske, 2007; Stern, 2004). Merging silicone's high oxygen permeability with general soft lens properties, advanced plasma coatings and intrinsic wetting agents, SiHy lenses can offer significant advantages over traditional polyHEMA-based hydrogels.

Most notable is the significant reduction in signs and symptoms associated with corneal hypoxia. A threeyear clinical study compared 30-night continuous wear of SiHy lenses with daily wear of low-Dk/t HEMA (LDW) lenses (Bergenske, 2007). The patients wearing SiHy lenses showed significant reductions in limbal and conjunctival hyperemia and corneal neovascularization as well as less myopic progression, and they reported significantly fewer symptoms of lens awareness, redness, dryness, photophobia, and blurred vision versus the LDW group. Further, the wearers of low-Dk/t HEMA-based lenses exhibited significant increases in limbal redness, papillary conjunctivitis, corneal staining, and myopic progression and reported more frequent dryness and blurred vision as compared to no lens wear.

SiHy lenses are a healthy option for continuous wear and daily wear (Bergenske, 2007; Efron, 2008; Dumbleton, 2006). They can be problem solvers for patients who have comfort and dryness symptoms (Dumbleton, 2006; Chalmers, 2008), and they tend to exhibit low levels of protein deposition (Jones, 2003). They are available in sphere, toric, multifocal, and made-to-order parameters to fit almost any refractive error.

Yet the adoption of SiHy lenses has been slower than first predicted. In 2008, silicone hydrogels accounted for only 29 percent of soft contact lens sales worldwide (Morgan, 2009), although in the United States it is up to 50 percent (Contact Lens Institute, 2008) and fits and refits into SiHy lenses are about 65 percent (Nichols, 2010). For those who have not yet embraced SiHy lenses, this article provides information and insights to help overcome the Law of Inertia and reap the benefits that SiHy lenses can bring to your patients and your practice.

The Silicone Story: Why Dk Still Matters

The cornea needs oxygen to stay healthy—ideally, the same amount of oxygen in the atmosphere, around 21 percent. Chronic corneal hypoxia has plagued contact lens wearers since the dawning of the age of contact lenses. Remember central corneal clouding and corneal striae and folds? Even with optimized polyHEMA lens materials and thinner designs, corneal hypoxia can impair corneal physiology and cause epithelial changes, microcysts, stromal thinning, endothelial polymegethism, limbal hyperemia, and neovascularization. Long-term chronic hypoxia can ultimately lead to corneal changes that result in intolerance to contact lens wear in a condition that has been termed corneal exhaustion syndrome (Sweeney, 1992).

Even daily wear patients can manifest subtle signs of corneal oxygen deprivation, especially those wearing thicker lens designs—hyperopes, presbyopes, astigmats, and high myopes whose lenses are thicker at the lens periphery. Keep in mind that published Dk/t values are measured using the center thickness of a �3.00D lens. Oxygen transmission at a given point on the lens will vary according to lens thickness, being lower through thicker portions of the lens, and this can cause localized edema (Holden, 2006). The patient who reports vague ocular discomfort, blurred vision, and red eyes may be suffering from chronic corneal hypoxia, not allergies or solution sensitivities.

Meeting the oxygen challenge was the driving force behind SiHy material development. With oxygen transmissibilities (Dk/t) ranging from 55 to 175 x 10⁻⁹, SiHy lenses can offer patients healthy options that better meet the cornea's oxygen demands.

But how much oxygen is enough? The answer: more than we used to think, and it depends upon the cornea. Numerous scientific and review articles discuss the science of oxygen permeability (Dk), oxygen transmissibility (Dk/t), oxygen flux (J) and their clinical significance (Brennan, 2005; Papas, 1998). These will not be covered here, but to summarize: there is no consensus. However, recent publications on the topic continue to question the minimum Dk/t levels needed to provide for corneal oxygen demands (Alvord, 2007; Bonanno, 2009).

Limbal hyperemia results from oxygen deprivation at the peripheral cornea. The limbus is the sole provider of epithelial stem cells, those precious precursors of new epithelial cells, necessary to epithelial regeneration and recovery from injury. Any damage to the limbus and the stem cell supply chain can lead to recurrent corneal erosions, chronic keratitis, and vascularization (Stapleton, 2006). One of the most visually dramatic benefits to refitting hydrogel patients with SiHy lenses is the marked improvement in limbal and conjunctival hyperemia.

There is individual variation in corneal oxygen demand and swelling response. Some corneas can tolerate lower-Dk lenses, while others have higher demands and exhibit swelling under the same conditions (Mueller, 2001; Moezzi, 2009).

Why Make the Switch?

Prevention/Maintenance For many, the SiHy oxygen story is reason enough to switch patients to SiHy lenses. Why risk corneal hypoxia and compromised corneal physiology when you can avoid it? Because some patients have higher corneal oxygen demands than others do, and there's no feasible way to identify them beforehand, it's prudent to fit higher-Dk lenses to start with (an ounce of prevention being worth a pound of cure). This is especially true for patients wearing thicker lens designs, such as hyperopes, presbyopes, and astigmats, as well as any patients who may sleep or nap in their contact lenses.

For those patients in polyHEMA lenses who show signs or symptoms of hypoxia, refitting into SiHy lenses should be standard protocol. Keep in mind that subtle symptoms of lens dryness, discomfort, and reduced wear time could indicate hypoxia, although this is not well understood. Even if signs and symptoms are subclinical or absent, switching patients into SiHy lenses may forestall hypoxic issues and provide a measure of preventive maintenance.

Comfort There is some indication that SiHy lenses can provide greater comfort for many patients (Chalmers, 2009). Higher oxygen transmissibility reduces symptoms of hypoxia; lower water content may prevent on-eye dehydration (McConnville, 1997); surface treatments and intrinsic wetting agents can provide a continuously wettable lens surface. Greater comfort can allow patients to successfully wear their lenses longer and may reduce the likelihood of patient dropout from contact lens wear.

SiHy lenses are the newest technology, offering the latest advances in material science and lens designs. They not only provide higher oxygen transmissibility, but also offer important features that enhance the lens-wearing experience.

Aside from the obvious clinical reasons to fit SiHy lenses, there are other reasons to make the switch.

Patient Loyalty When patients realize that you take the time and effort to recommend and provide state-of-the-art products and services, they realize that you care about your profession—and that you care about them. When you refit a symptomatic HEMA-wearing patient with a SiHy lens and his chronically red eyes brighten and whiten, you will create a loyal patient. And that loyal patient stays with your practice and refers his family and friends. SiHy lenses can be practice builders.

Profitability Positioned as premium products, SiHy lenses typically command higher prices and refitting fees. Contact lens patients understand value and many are willing and able to pay for it. Your time and expertise are required to fit and follow up patients wearing these lenses, so don't flinch at charging appropriate fees.

By providing the new lenses with the recommended care solutions (bundling), you not only encourage compliance but also increase practice profits. When a year's supply of lenses and solutions are provided (rather than a three- or six-month supply), some practitioners have realized a direct correlation between an increase in multiple unit sales and increased overall practice revenues (Kerr, 2007).

Offering flexible payment options, such as a monthly direct debit, allows patients to spread the annual cost into monthly payments and budget for their lens costs. Comparing the incremental monthly cost of the new lenses to less important purchases (such as fancy beverages or an evening out) helps to put the significant advantages of their new lenses in perspective. And don't forget to check patients' health insurance plans. Many cover the costs associated with contact lenses. Switching to SiHy lenses can be a significant profit generator in your practice.

Professional Image SiHy lenses are widely considered to be the best-in-class products and offer a variety of important benefits to your patients. Your patients place their trust in you to provide them with the information and products that will enhance their vision and their lifestyles. When you recommend the best products for patients, you confirm that you are up-to-date and providing them with the latest technologies. Fitting SiHy lenses helps establish your practice as being proactive and progressive.

How to Make the Switch

Switching to SiHy lenses may require overcoming the inertia of self-imposed barriers and misperceptions. These lenses are problem solvers, easy to fit, comfortable, and are compatible with many lens care solutions. Yes, they are premium products and cost a little more, but they offer real value to your patients—and your practice. Today's consumers are savvy and want to be engaged in the healthcare decision process. Don't wait for them to ask you about SiHy lenses or worse, take their business elsewhere to a practitioner that offers them the latest technologies and innovations.

Here are some pointers on how to get started.

Paradigm Shift Switching successfully to SiHy lenses may require a "paradigm shift" in your approach to patient management. Inertia being what it is, it may be difficult to shake off the mindset of "if it ain't broke, don't fix it." However, don't assume that your patients are problem-free because they don't complain to you about their lenses. They may have accepted discomfort, dryness, shorter wearing times, and red eyes as "normal" aspects of lens wear. They may even be concerned that if they complain, you may recommend that they stop wearing their lenses altogether! Learn to probe, inquire, and be conversational with patients. Ask them to describe their lens wearing experience rather than to answer "yes" or "no" closed-end questions. Be proactive in anticipating the problems they are likely to have, and assure them that you will work together to explore options and alternatives to address those issues.

SiHy lenses are high-tech, premium products that offer significant benefits to your patients. And they come at a higher cost. Learn to be comfortable discussing your reasons for recommending SiHy lenses and the higher fees they entail. Even in recessionary times, healthcare consumers understand value and especially the importance of their eyes and vision. Being non-judgmental about their willingness and ability to afford the option that is best for them is your professional obligation and responsibility.

Prepare Your Practice Make sure you and your staff understand SiHy lenses by taking appropriate courses and reading relevant articles and background information. Useful articles and information can be found at sites such as www.siliconehydrogels.org and www.clspectrum.com. Use the technical support of the lens manufacturers and their sales representatives. If you and your staff wear soft lenses and haven't already done so, refitting yourselves into SiHy lenses allows you to experience the benefits and puts you in a better position to recommend them to your patients.

Choose a lens manufacturer that offers a family of SiHy products (sphere, toric, multifocal) and become familiar with fitting these lenses. For example, several manufacturers of SiHy lenses include spherical, toric, and multifocal product lines in a useful array of parameters. Display the marketing support materials available from the manufacturer in the reception area, dispensing area, and exam room. This makes the discussion of transitioning that much easier.

Make sure that the lens care solutions you stock and recommend are compatible with SiHy lenses and that your staff members are trained to properly advise patients in their proper care and handling. Use the opportunity of the dispensing visit to revisit and reinforce all aspects of proper lens care. If appropriate, this is an ideal time to upgrade the lens care regimen; for instance, to take advantage of the benefits of hydrogen peroxide systems with SiHy lenses in terms of reduced corneal staining compared with some multipurpose care solutions.

Patient Selection It's hard to imagine a soft lens patient who doesn't stand to benefit from being fitted or refitted into SiHy lenses; however, there are certain groups who may benefit the most:

● Patients Who Have Lens-Related Problems or are Dissatisfied With Their Contact Lenses They may report dryness, discomfort, redness, or reduced wearing times—all of which can be improved with SiHy lenses.
● Contact Lens Dropouts They deserve another chance with the newer technologies.
● Patients Wearing Thicker Lens Designs This includes hyperopes, presbyopes, and astigmats.
● Patients Who are Likely to Sleep or Nap in Their Lenses Sooner or later, this includes pretty much everyone. Think emergency personnel, frequent fliers, shift workers, new parents, teenagers, backpackers, etc.
● Potential LASIK Candidates A study by Schein et al (2005) provided some evidence suggesting that there may be less risk of permanent vision loss in 30-night overnight wear of lotrafilcon A (Air Optix Night & Day Aqua, Ciba Vision) SiHy lenses than in LASIK.

Your Next Move

Once you are thoroughly familiar with the science and benefits of SiHy lenses, make sure everyone in the office reinforces the message of the new state-of-the-art technology whenever appropriate. Ideally, patients could hear about SiHys several times during their office visit, starting with marketing materials in the reception area, then from the assistant who performs preliminary testing, next from the practitioner during the exam, and finally at check-out.

During the preliminary testing, the assistant can ask each spectacle patient who intends to update his glasses or wants a backup pair, "If you were told you are a candidate for contact lenses, would you be interested?" You'll be surprised how many will say yes, and that provides the segue into the benefits of the new SiHy materials. Ask current lens wearers, "How do you rate the comfort of your lenses, on a scale of 0 to 10?" Few will rate their lenses a 10, leading into the next question, "What if a new state-of-the-art lens technology could give you even greater comfort and whiter eyes?" Most patients will find the prospect intriguing.

During the exam, if the patient is a current lens wearer or a candidate, mention the new SiHy technology, positioning it as the current state-of-the-art. Compare it to something tangible, such as the difference between analog TV and high definition. Point out that the opportunity to wear the very best lenses is worth the extra cost. Why wouldn't they want better healthy lens wear, comfort and wearing flexibility?

SiHy lenses can offer significant health benefits. However, for most patients who are asymptomatic or have "minor" issues with their lenses, this is not a terribly compelling reason to change. Rather than simply telling them that these lenses are better, put it in terms of "what's in it for them." Explain that the new lenses may give them more flexibility in their wearing schedules, decreased redness, and better comfort. Give them tangible, meaningful benefits that are relevant to their specific situation.

Practical Examples

Switching patients into any lens modality requires not only expertise, but also effective communication skills. The following hypothetical case examples provide useful scenarios to demonstrate how you might switch specific patients into SiHy lenses.

Spherical Lens Patient This patient is wearing a monthly replacement hydrogel lens and is in your office for a scheduled follow-up appointment and a new supply of lenses. At the reception desk, the patient receives a brochure on SiHy lenses to read after signing in. During the preliminary examination, the paraoptometric assistant asks the patient to rate lens comfort and the response is a "9." Her reply: "Great! There are new state-of-the-art lenses available that may give you even better comfort. They're called ‘silicone hydrogels,’ and since you're due for a new supply, the doctor will probably mention these as a new option for you."

During the examination, you ask probing but conversational questions during the case history. "About how many times per week do you sleep or nap in your lenses?" "How many hours do you normally wear your lenses? At what point do they start becoming less comfortable?" "Would you be interested in new lenses that may provide better comfort and are more breathable?" These are non-threatening questions that provide opportunities to discuss SiHy benefits and make your recommendation.

After biomicroscopy, you can discuss any ocular signs that may be improved by the use of SiHy lenses. Signs such as limbal hyperemia, corneal neovascularization, and epithelial microcysts can be indications to switch to a SiHy lens.

Toric Lens Patient This patient wears traditional hydrogel toric soft lenses and is relatively asymptomatic except for mild redness. Upon entering the office, the patient notices a poster featuring a SiHy lens with a moisturizing system for all-day comfort. At sign-in, the patient receives a brochure about a new SiHy toric soft lens.

During the preliminary exam, the assistant inquires about lens comfort, which is rated an "8." Her response, "You'll be glad to hear that there are new, state-of-the-art toric lenses that may give you better comfort. They're called ‘silicone hydrogels.’ They're more comfortable and they let more oxygen through to your eyes. During the exam, the doctor may mention these and recommend them if they're right for you." She notices some perilimbal redness and adds, "Many of our toric patients are wearing silicone hydrogels and love how they can wear their lenses more comfortably and their eyes are whiter."

During the case history, you ask a series of openended questions. "How do you feel your eyes look?" The patient may respond, "OK, I guess. Maybe they are a little bit red, but I guess that's normal." You reply, "What if I told you there are lenses that can help clear that redness; that your eyes can probably look and feel much better with these new state-of-the-art lenses?" Patient: "I'd be very interested!"

During biomicroscopy, you notice mild epithelial microcysts and moderate limbal hyperemia, especially inferiorly where the prism ballast lens is thickest. You say, "I'm seeing changes in your eyes due to the lenses you've been wearing. There is some irritation on the surface of your eye, and increased redness. It's time to move you into the new, state-of-the-art technology of silicone hydrogel lenses—they are available in your prescription, and they'll allow more oxygen to your eyes for whiter eyes. You may also experience greater comfort."

Presbyopic Multifocal Patient At the annual checkup, an emerging presbyope arrives at your office for a prescription update and finds a video about contact lens options for presbyopia playing in the reception area. At check-in, the receptionist offers a brochure on multifocal SiHy lenses. During the preliminary exam, the patient complains of the need for reading glasses. The assistant says, "Today there are state-of-the-art contact lenses that correct your distance and your near vision. They're called silicone hydrogel multifocal lenses, and they correct the entire range of your vision." Then she asks the usual question, "How would you rate the comfort of your lenses?" The patient responds, "A ‘7,’ mostly because of dryness." The assistant responds, "The new silicone hydrogel lenses are super ‘breathable,’ allowing more oxygen to your eyes, and some have moisturizing systems to make them much more comfortable. The doctor will check your eyes and will let you know if these lenses are right for you."

During the case history you ask the series of questions, "How do your lenses feel?" Patient: "Fine, I guess." You note the equivocal response and probe further. "Great! How many hours do you normally wear them?" Patient: "From 7 a.m. to 7 p.m." You respond, "OK, so they come off at 7 p.m. Do they feel exactly the same as when you put them on in the morning?" Patient: "No, they are not as comfortable. They start to feel dry." Your response: "At what point do they become less comfortable?" Patient: "Around mid-afternoon. Sometimes I have to take them out at work, they start to feel so dry."

Exam results indicate an increase in add power for reading. Biomicroscopy also reveals mild hyperemia. You say, "I'm finding that you need a stronger prescription for reading, and I'm seeing some redness from your current lenses. There are new, state-of-the-art contact lenses called silicone hydrogels that are available in multifocal prescriptions to correct your distance, intermediate, and near vision. These high-tech lenses transmit more oxygen to your eyes and may be less prone to drying while you're wearing them. That means better comfort, whiter eyes, and, you won't have to wear those reading glasses!"

When the patient is dispensed the new multifocal SiHy lenses, you decide to upgrade the lens care to a hydrogen peroxide system to avoid any potential solution incompatibilities and maximize success.

Practical Matters

Refitting patients from hydrogels into SiHy lenses is straightforward, but there are certain things to watch for. We are presenting these to you to inform you, not to discourage you. Don't allow them to become barriers. Consider them "heads-up" advice that will help you be successful with these lenses.

Lens Awareness Some SiHy lenses have a higher modulus and lower water content compared to some HEMA-based lenses. Because of this, it's not uncommon for patients to report increased lens awareness during adaptation to the new lens material, usually just two to three days. Reassure patients that this is normal and expected. Educating these patients about what to expect will be key to ensuring their success.

Microcysts If a patient has been refitted from a low-Dk hydrogel, you may see an increased number of microcysts within a week of refitting as the cornea adjusts to the increased oxygen levels. These should not be symptomatic and usually subside within one to three months (Keay, 2000).

Lens Deposits SiHy lenses tend to exhibit less protein deposition compared to traditional HEMA lenses (Jones, 2003), while some SiHy materials tend to attract more lipid deposits than traditional hydrogel materials do (Carney, 2008).

Dispensing and Lens Care Even if a patient is a veteran lens wearer, it is advisable to have a dispensing session with the new SiHy lenses. This is an opportunity to educate patients, and it allows them to handle the lenses and ask any questions. It is especially important to reinforce the need for proper hygiene and lens care at this time. Re-evaluate the patient's lens care regimen and change systems if necessary. There have been reports of corneal staining associated with specific SiHy lens and multipurpose solution combinations (Jones, 2002).

Non-Hypoxic Problems Although SiHy lenses minimize hypoxia-related problems, mechanical, inflammatory, and infectious complications are still possible. As with any lenses, neither patient nor practitioner should ever become complacent and regard these lenses as a panacea or without the potential for complications. The rate of corneal inflammatory events with SiHy lenses may be increased compared to hydrogel lenses (Szczotka-Flynn, 2007). Keep in mind that at times it may be patients and their wearing habits/lack of compliance that trigger these scenarios, not the lenses.

What's Next

Knowledge is power. SiHy lenses are technologically superior products and are the most well-researched lenses in history. Yet many experience inertia when it comes to incorporating them into their practices. If you have not yet started fitting SiHy lenses or fully embraced their benefits and your practice is in a state of inertia, we hope that the information in this article has provided the knowledge and power you need to overcome Newton's First Law of Motion. CLS

The authors wish thank Ciba Vision for its assistance with this article.

For references, please visit www.clspectrum.com/references.asp and click on document #178.