GP ANNUAL REPORT

GP Annual Report 2014

Areas of potential growth continue to be scleral lenses, corneal reshaping designs, multifocals, and hybrids.

By Edward S. Bennett, OD, MSEd, FAAO

In 2014, GP lenses continue to be a viable contact lens modality. Even though conventional spherical GP lens use continues to decrease, specialty designs—notably scleral lenses—are increasing at a rate to offset the spherical lens decline. In the United States, a 0.7% decline has been reported (2013 versus 2012), with a total of 8% refits and new fits into GP lenses and an additional 2% fit into hybrid lenses (Nichols, 2014). The good news is this is the first year that PMMA lenses did not represent as much as 1% of the market, and their decline is further evidence of practitioner preference for the increasingly high-quality GP lenses available today. Internationally, GP use is similar to past years—12% of contact lens fits are with standard GP lenses, and an additional 1% are fit into corneal reshaping lenses (Morgan et al, 2014).

The areas of growth, or potential growth, remain scleral lenses, corneal reshaping designs, multifocals (both corneal and scleral), and hybrids. When the 70-member GP Lens Institute (GPLI) Advisory Board—consisting of practitioners who are known for their expertise in fitting GP and specialty soft lenses—were polled as to what they believed was the greatest advancement in GP lenses in 2014, 42 of the 46 respondents specifically indicated scleral lenses. When asked where they thought the GP market was going in the next five years, scleral lenses were again predominant, but the aforementioned categories of corneal reshaping, multifocals, and hybrids were also considered important by many of the respondents (Figure 1).

Figure 1. GPLI Advisory Board Member responses to: Where is the GP market going in the next five years?

Scleral Lenses

The scleral lens phenomenon continues to progress as more practitioners fit this modality and newer and more advanced designs enter the marketplace. Not only do these lenses change people’s lives, but they are beginning to impact practitioner prescribing habits pertaining to healthy (astigmatic and presbyopic) eyes. There still exists the challenges of lens cost (if not reimbursed), and lens handling (with larger designs).

Surprisingly, when polled as to what percentage of each of six different contact lens corrective options they fit to their last 100 irregular cornea patients, the GPLI Advisory Board members, on average, fit 43.74% of them into scleral lenses (Figure 2). This, of course, reflects the prescribing patterns of a group of specialty contact lens fitters.

Figure 2. What percentage of each of the following contact lens modalities were fit on the past 100 irregular cornea patients?

Tables 1 and 2 provide a more balanced perspective as it pertains to prescribing habits of U.S. practitioners in general. These are the results of a survey on contact lens prescribing habits sent by Bausch + Lomb (B+L) to all optometrists in the United States, ultimately resulting in close to 300 respondents. Table 1 shows that their current prescribing habits with irregular cornea patients frequently or always include corneal GP lenses in more than 68% of the cases, as compared to approximately 19% with both sclerals and soft torics, 16% with hybrids, and 10% with specialty soft lenses for irregular corneas. However, Table 2 shows that more than 34% prescribed more scleral lenses this year than the past year, as compared to approximately 23% for hybrids, 20% for specialty soft, 8% for toric soft, and 6% for corneal GP lenses.

It is evident that scleral lenses are the primary area of excitement for contact lens laboratories, according to Quality Contact Lens and the Contact Lens Manufacturers Association (CLMA) President Ken Leonhard: “I am very excited about scleral lenses and their initial comfort, in large part due to the remarkable success stories communicated to me by my practitioners.”

Scleral Lens Fit Scales There have been new developments in scleral lens resources as well. The Michigan College of Optometry (MCO) contact lens faculty have developed the “Scleral Lens Fit Scales,” which are available at www.ferris.edu/ScleralLensFitScales. This scleral lens fit assessment tool is based on a tear layer thickness guide (Dinardo, 2014). Participants in an online survey were asked to select which of several options best represented central clearance of a scleral lens design. They were then shown the MCO scleral lens fit scale system and subsequently were asked to grade the central vault of several lenses. The accuracy of all respondents increased significantly after using the lens fit scale. They, therefore, concluded that the MCO scleral fitting guide can improve both accuracy and confidence in assessing scleral vault.

Optical Coherence Tomography (OCT) and Scleral Lens Fitting Anterior segment OCT is a valuable tool for measuring the radii of anterior scleral curvatures by image processing and mathematical calculation (Choi et al, 2014). Caroline and André (2014) have shown that scleral lenses have a tendency to decenter slightly inferior-temporally based upon their OCT imaging observations at Pacific University. Inferior decentration results from several factors, including gravitational force secondary to the weight of the lens, the upper lid pushing the lens inferiorly, and OCT observations showing that the superior sclera is indeed higher compared to the inferior sclera. Therefore, when the lens is placed onto the eye, it lands first at the point of greatest elevation and then is forced in the opposite direction. In addition, as the nasal sclera is significantly higher compared to the temporal sclera (more in the right eye than in the left eye, on average), this results in a dark fluorescein thinning pattern observed in the superior-nasal portion of the peripheral cornea. They concluded that some of the new technology, such as toric haptic and quadrant-specific designs, may result in improved centration in these cases.

There is much recent interest is the use of OCT images to assess how much a scleral lens settles (i.e., decreases in tear lens sagittal height) over time. Recent studies have found that overall settling of scleral lenses averages approximately 100 microns, although it can vary among different designs and depends on the amount of time that the measurement is made after initial application. The great majority of settling occurs in the first four hours (Kauffman et al, in press; Michaud, 2014; Caroline and André, 2012).

New Designs Scleral toricity tends to increase in irregular cornea patients and can impact alignment with larger-diameter scleral lenses, possibly resulting in problems such as specific peripheral blanching, rocking, excessive movement, and decentration. Increased patient awareness can also result, so toric peripheral curves are recommended for larger (≥18mm overall diameter [OAD]) scleral lenses (Bennett et al, 2014). Many of the recently introduced lenses utilize exciting new manufacturing technologies that allow for a more precise alignment of lens periphery to sclera.

Enter the Zenlens (Alden Optical) with Dr. Jason Jedlicka as a designer. Manufactured in Boston XO and XO₂ materials (B+L) with OADs of 16.0mm and 17.0mm, it is available in both prolate and oblate designs to fit a wide range of corneal shapes. It offers seven different edge profiles as well as the ability to correct residual astigmatism on the front surface and incorporate toric peripheral curves to create better scleral alignment (Figure 3). It also incorporates a so-called “Smart Curve” in an attempt to maintain a constant base curve despite variation in lens sagittal depth (Figure 4).

Figure 3. Alden Optical’s Zenlens is made in the Boston XO and XO₂ materials, has OADs of 16.0mm and 17.0mm, and is available in both prolate and oblate designs.

Figure 4. In this example, the Zenlens’ Smart Curve maintains a constant base curve despite the variation in lens “sag.” This is very useful when you need to optimize corneal clearance, but are satisfied with the base curve.

The EyePrintPro (EyePrint Prosthetics, LLC) is a prosthetic scleral cover shell that improves vision by creating a new, smooth refractive surface for the eye. The EyePrintPro, like a fingerprint, is unique to each individual. It starts with the EyePrint Impression Process, which captures the precise curvatures of the entire ocular surface. This comfortable and gentle molding process allows practitioners to fit complicated ocular irregularities with precision. The EyePrint Impression is shipped to EyePrint Prosthetics for digitizing and prosthetic scleral cover shell design. Using 3D scanning and computer numerically controlled (CNC) machining systems, an exact match is achieved to each individual cornea and sclera (Figure 5). The concept of EyePrint Prosthetics was developed by Dr. Christine Sindt in collaboration with Keith Parker, president of Advanced Vision Technologies (AVT). This is a promising new option, certainly for irregular cornea and dry eye patients.

Figure 5. EyePrintPro uses 3D scanning technology and CNC machining systems to achieve an exact match to each individual cornea and sclera.

There are many other new designs, either recently introduced to the market or soon to come, including the following:

• Blanchard Contact Lens has introduced an Anterior Surface Toric add-on for its Mini Scleral Design, Onefit P+A, and Onefit Cone lenses featuring Sector Prism Technology process, which confines the prism ballast within an area of lenticulation outside of the optical zone while maintaining a uniform edge thickness for the entire circumference of the lens. The company is also working on the final design characteristics of a reverse geometry scleral lens designed specifically for post-refractive surgical oblate corneal topographies. This new design may increase ease-of-fit and visual performance for highly ectatic, oblate, post-refractive surgical patients.

• Menicon introduced Menicon Z Large Diameter Blanks in clear tints last December to meet the demands of laboratory customers desiring scleral lenses in a hyper-Dk (163) lens material.

• The Custom Stable lens by Valley Contax is now available from 14.8mm to 17.8mm OAD. Front cylinder options, as well as toric landing zone options for irregularly astigmatic corneas and scleras, are also now available.

• A new simplified AVT Scleral Diagnostic Fitting System (AVT)—including a wide selection of central sag values, limbal clearance zones, and tangent carrier angles—will be introduced at the American Academy of Optometry meeting in November in Denver. The diagnostic lenses will be labeled to be easier for practitioners to utilize and understand, and a marking system will allow for more accurate evaluation of the limbal area.

• Art Optical Contact Lens, Inc. intends to release a new scleral lens design by the end of 2014.

Scleral Lenses for Healthy Eyes One of the great controversies in the GP industry today is whether scleral lenses for the correction of normal eyes (i.e., astigmatic and presbyopic) will ultimately represent an important segment of the contact lens industry. When polled, approximately 61% of the GPLI Advisory Board thought that they would have a mild impact in the next three years, as opposed to none or very little impact (13%), moderate impact (15.2%), or will become a mainstream correction option (10.9%) (Figure 6).

Figure 6. In the next three years, what impact do you feel that scleral lenses for healthy eyes (i.e., astigmats, presbyopes) will have on the contact lens market?

With initial comfort rivaling soft lenses (Woo, 2013) and the benefits of rigid lens optics, time will tell whether these benefits allow them to compete favorably with other contact lens designs and materials. Many laboratories believe that they will have an impact based upon the many new multifocal designs being introduced (to be discussed in the multifocals section).

Other Irregular Cornea Designs

The benefits and applications of corneal GP and hybrid designs are still evident today, and the latter modality appears to be increasing in use. Rigid lens optics are important for the great majority of irregular cornea patients, and the ability to correct for wavefront aberrations can provide an even greater benefit visually to GP-wearing keratoconus patients (Yang et al, 2014).

The benefits in post-ocular trauma cases are evident as well. Twelve young boys, all less than 15 years of age and having experienced ocular trauma, were fit into GP lenses (Pradhan et al, 2014). Eleven of the 12 boys were still wearing the lenses 15 months later, with seven achieving a greater-than-two-line increase in visual acuity as compared to spectacle correction.

It is also interesting to note that bitoric lenses may have applications with certain irregular cornea patients, often post-surgical patients exhibiting mixed astigmatism via corneal topography (Bennett et al, 2014). Recently, Phan et al (2014) compared records of post-penetrating keratoplasty (post-PK) patients being managed with bitoric GP lenses versus controls (post-PK patients wearing spherical GPs). The average astigmatism in the bitoric group was 10.00D, as compared to 3.30D in the spherical group. The contact lens-corrected visual acuity between the two groups was the same, as was the number of contact lenses per eye to achieve success, so it was concluded that bitoric GP fitting in post-PK patients is not more complex than spherical fitting is.

New designs are entering the market as well. Hybrid lenses, in particular, can result in good patient satisfaction and vision-related quality of life (Hashemi et al, 2014).

• SynergEyes, Inc. is expanding its current line of hyper-permeable UltraHealth designs; the company will soon release Ultrahealth Flat Cornea for extremely oblate post-surgical corneas.

• Carter Contact Lens, Inc. has been developing a large-diameter (11.0mm) reverse geometry GP primarily for fitting corneal transplants, post-RK, failed LASIK, corneal ring segments, and large cones. Its fitting set is available in two optical zone diameters of 7.0mm and 8.0mm; the reverse curve width allows the lenses to vault a large diameter—8.2mm and 9.2mm, respectively. The reverse curve difference in the fitting set is four diopters; however, all parameters can be made to order. The lenses can be made in toric and bifocal designs.

Corneal Reshaping

According to recent data provided by Dr. Michael Lipson (2014), estimates indicate that 6,000 to 8,000 U.S. practitioners are certified to fit corneal reshaping lenses. The certification necessary to be able to fit these designs is relatively easy and can be performed online either via www.paragoncrt.com for Paragon Vision Science’s Corneal Refractive Therapy designs (i.e., Paragon CRT and RG-4) or www.bausch.com for any of the Vision Shaping Treatment designs (i.e., BE Retainer, Precision Technology Services Ltd.; CKR, Eye Research Associates, Inc.; Contex OK E-System, Contex, Inc.; DreamLens, various labs; Emerald, Euclid Systems Corp.; NightMove, Gelflex and Advanced Corneal Engineering, Inc.; MiracLens, MiracLens, LLC; Orthofocus, Progressive Vision Technologies; Super Bridge and E-Lens Overnight Orthokeratology Lens, E&E Optics; Vipok, Vipok Inc.; and Wave Contact Lens System, Custom Craft Lens Service, Metro Optics, and X-Cel Contacts).

The challenge appears to be educating consumers, notably parents, about the benefits and safety of corneal reshaping. The safety issue has recently been addressed by Bullimore et al (2013), who found that the overall estimated incidence of microbial keratitis (MK) with corneal reshaping is 7.7 per 10,000 years of wear; it is 13.9 per 10,000 patient-years for children. They concluded that the risk of MK with overnight corneal reshaping contact lenses is similar to that with other overnight modalities.

It also has been found that if parents are informed and feel that the modality is safe, and if they are informed of the positive evidence of the myopia control effects, they are quite receptive to this modality for their children (Cheung et al, 2014) (see “Differing Opinions of Myopia Control” on p. 27).

Recent research is continuing the trend toward evaluating designs that result in a peripheral myopic defocus to retard eye growth, and the next few years should result in much information about how to design corneal reshaping GP lenses and peripheral plus power soft lenses to optimize myopia control. The design of a corneal reshaping lens—incorporating a reverse curve—as well as the resulting corneal changes can impact eye growth. Recently, it has been reported that corneal reshaping induces non-uniform changes to the central and paracentral regions (Maseedupally et al, 2013). Myopia control may be influenced by this non-uniformity, which may influence peripheral refraction profiles. In addition, it has been found that there is greater likelihood for success with corneal reshaping if the following conditions exist: lower initial myopia, low levels of parental myopia, longer anterior chamber depth, greater corneal power, more prolate corneal shape, and larger iris and pupil diameters.

Paragon Vision Sciences recently introduced some enhancements to its CRT fitting process. In April 2014, the company introduced an enhanced CRT Diagnostic Dispensing System to allow for temporary dispensing of the diagnostic lenses until the final parameters are determined and new lenses are ordered in Paragon HDS 100 material. Once the new lenses are dispensed, the diagnostic lenses are cleaned, disinfected, and replaced to the CRT set for continued diagnostic use.

In addition, the GP material in the enhanced CRT Diagnostic Dispensing System was changed from Paragon HDS 100 (100 Dk, ISO/ANSI Method) to Paragon HDS (40 Dk, ISO/ANSI Method.) Paragon has always concluded that the higher-Dk material, Paragon HDS 100, was the best material for long-term wear. For relatively short-term diagnostic purposes, however, Paragon HDS offers sufficient Dk and improved durability.

A second enhancement is the handling tint of the CRT lens, which has changed in the updated Diagnostic Dispensing System from light green to light orange. The new orange tint is to differentiate the CRT diagnostic lens from the CRT prescription lens. The orange tint does not affect evaluating the tear pattern on the eye, with or without a Wratten filter.

Finally, Paragon CRT corneal reshaping lenses feature a laser mark of the lens parameters (base curve, return zone depth, and landing zone angle). The new orange CRT diagnostic lens features an additional, larger laser mark that spells out “Not For Sale.” This is to distinguish diagnostic lenses from those dispensed as prescription lenses. CRT patients will benefit in that once the final parameters are determined with the diagnostic lenses, the patient will be ensured to receive fresh, new lenses manufactured in Paragon HDS 100, rather than lenses that may have been worn multiple times by previous patients and returned back into the CRT Diagnostic Dispensing System. While this has not been an issue to this point in time, with the rapid expansion in CRT fitting, Paragon believes that this will be a future benefit for patients and practitioners alike.

Multifocals

A number of new corneal, hybrid, and scleral multifocal lens designs are being introduced, reflecting the continuing interest in lenses incorporating rigid lens optics for satisfactory—if not excellent—vision at multiple distances.

Corneal Designs Here is a look at several new corneal designs.

• Conforma Contact Lenses now offers expanded fitting options for its VFL 3 Progressive Multifocal lens design. Recently added Toric Peripheral Curve (TPC) options will offer astigmatic presbyopes the opportunity to experience quality vision at distance, intermediate, and near. The new TPC options will help improve corneal alignment, centration, and comfort for ≥2.00D of corneal astigmatism. This improved lens-to-cornea fitting relationship will maximize lens centration and add capabilities of the VFL 3 aspheric design.

• Art Optical will be releasing a new center-near GP design by the end of 2014 or the beginning of 2015. It will feature a controlled near zone diameter with aberration-controlled distance optics. This new design will supplement Art Optical’s Renovation Multifocal design series and join its recently released mPower! simultaneous center-distance option.

• AVT’s Naturalens Progressive modality—featuring the Variable Inverse Periphery Technology that offers high add options with its multi-zone aspheric front surface design—now offers wider mid-range optics with an expanded intermediate zone with the Naturalens Mid-Pro. This allows for a wider field of mid-range visual requirements such as computers and office work. In addition, AVT’s new Transbylite Thin translating bifocal offers a viable option for patients desiring clear, consistent near focal vision. The Transbylite back surface incorporates the VIP Technology to help provide a forgiving, comfortable fitting relationship. The VIP Technology provides improved tear exchange, potentially allowing for a smooth transition of lens position from distance to near and back to distance visual demands.

Hybrid Designs SynergEyes is in the process of developing a multifocal in the UltraHealth design and is hopeful to introduce it to the market in the second quarter of 2015.

Scleral Designs Two options are becoming available in the scleral design space.

• Anterior surface aspheric multifocal optics for presbyopic scleral lens patients can now be ordered with the Blanchard Onefit P+A lenses. Optics are simultaneous plus centered and are produced in two distinct “Add Profiles”: a dominant eye profile and a nondominant eye profile. The dominant lens drops plus power within a shorter radius of the center of the lens, and the nondominant eye profile holds plus further within a radius from the center of the lens. All that is required is the manifest add correction and which eye is dominant.

• TruForm Optics has available both the DigiForm and the Tru-Scleral lenses in multifocal powers for presbyopic patients.

Other New Developments

Plasma Treatment One of the burning questions of the last five years or so is whether all GP lenses should be plasma treated, a process that thoroughly cleans the front surface of the lens and helps optimize initial wettability and possibly initial comfort. Although questions remain pertaining to how long this treatment lasts and what cleaners, treatments, etc., negatively impacts this treatment, the positive attributes appear to outweigh the challenges. Another benefit is that plasma treatment significantly decreases bacterial adhesion to fluorosilicone acrylate contact lenses (Wang et al, 2013).

Back Toric or Bitoric? This was the subject of a recent GP Insights column in Contact Lens Spectrum (Bennett and Parker, 2014). Considering that back-toric-only lenses induce a residual astigmatism that can reduce visual acuity, in combination with improved manufacturing methods for bitoric lenses, it has been argued that—with rare exception—back-toric GP lenses are not indicated for highly astigmatic patients. The only exception is when a patient has residual astigmatism that is corrected by the back-toric-induced cylinder. This can be determined easily via the GPLI Toric and Spherical Lens Calculator (www.gpli.info), which will recommend a back toric lens in these rare cases.

Resources Of course, the most important resource for practitioners fitting and troubleshooting GP lenses continues to be the laboratory consultants. These individuals can guide fitters through the entire cycle of lens selection, fitting, and troubleshooting while providing diagnostic sets and directing them to their website for fitting resources, often including videos and webinars. For scleral lenses, B+L/Boston has a Scleral Lens Series on YouTube; the GP Lens Institute has a series of archived webinars; and the Scleral Lens Education Society (www.sclerallens.org) offers numerous resources and videos as well as the opportunity to become a Fellow of this organization. For very comprehensive training on specialty contact lenses—including sclerals, corneal reshaping, presbyopia, coding and billing, and other related topics—the Global Specialty Lens Symposium (GSLS) (www.gslsymposium.com), to be held Jan. 22 to 25, 2015 at Bally’s Hotel and Casino in Las Vegas, is recommended. In addition, Dr. Eef van der Worp’s I-Site newsletter (www.netherlens.com) continues to provide a wealth of timely GP articles and listing of events on a monthly basis. The GPLI also continues to be a comprehensive source of GP educational resources including monthly webinars, archived webinars, and numerous other resources pertaining to spherical and all specialty GP lenses. A comprehensive coding and billing module from Dr. Clarke Newman and a Laboratory Consultant FAQs module were introduced in 2014, and a comprehensive staff training module is coming in 2015.

Summary

It is apparent that the GP industry remains alive and well and continues to thrive in 2014. Look for exciting new developments, particularly in the areas of scleral and corneal reshaping lenses in 2015. CLS

For references, please visit www.clspectrum.com/references and click on document #227.

Acknowledgements

GP Lens Institute Advisory Committee members: Roxanne Achong-Coan, OD; Bruce Anderson, OD; Mark André, FCLSA; Richard Baker, OD; Bruce Baldwin, OD, PhD; Melissa Barnett, OD; Doug Benoit, OD; Richard Brannen, OD; Marlane Brown, OD; Mile Brujic, OD; Jill Bryant, OD; Steve Byrnes, OD; Karen Carrasquillo, OD, PhD; Carmen Castellano, OD; Clark Chang, OD; Walter Choate Jr., OD; Gloria Chui, OD; Robert Davis, OD; Greg DeNaeyer, OD; Tim Edrington, OD, MS; Barry Eiden, OD; Art Epstein, OD; Bob Grohe, OD; Susan Gromacki, OD, MS; Jack Hartstein, MD; Cary Herzberg, OD; Jason Jedlicka, OD; Beth Kinoshita, OD; John Laurent, OD, PhD; Michael Lipson, OD; Derek Louie, OD; Ken Maller, OD; Amanda Marks, OD; Robert Maynard, OD; Brittney Mazza, OD; Brooke Messer, OD; Clarke Newman, OD; Craig Norman, FCLSA; Neil Pence, OD; Roxanna Potter, OD; Tom Quinn, OD, MS; Phyllis Rakow, FCLSA; Renee Reeder, OD; Susan Resnick, OD; John Rinehart, OD; Jack Schaeffer, OD; Muriel Schornack, OD; Joe Shovlin, OD; Jeff Sonsino, OD; Shawna Vanderhoof, OD; Cheri Vincent-Riemer, OD; Michael Ward, FCLSA; Ron Watanabe, OD; Bruce Williams, OD; Stephanie Woo, OD; and Joe Yager, OD.

CLMA Representatives: Josh Adams, Valley Contax; Dan Bell, Corneal Design; David Bland and Claire Venezia, B+L; Kurtis Brown, Menicon; Lee Buffalo, Blanchard; Dr. Mike Cook, Carter Contact Lens; Ken Crawford, TruForm Optics; Linda Glover, X-Cel Contacts; Arch Holcomb, ABB Concise; Mike Johnson, Art Optical; Dr. Jim Kirchner, SynergEyes; Troy Miller, Accu Lens; Keith Parker, AVT; Kevin Sanford, Conforma; Pam Scoggins, Paragon; Tom Shone, Alden Optical; and Al Vaske, Lens Dynamics, Inc.

Dr. Bennett is assistant dean for Student Services and Alumni Relations at the University of Missouri-St. Louis College of Optometry and is executive director of the GP Lens Institute. You can reach him at ebennett@umsl.edu.