GP LENS UPDATE
GP Annual Report 2013
Scleral lens expansion, new multifocal designs, and the potential of orthokeratology for myopia control are breathing new life into the GP lens market.
By Edward S. Bennett, OD, MSEd, FAAO
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 email@example.com.
The 2013 market for GP lenses is viable and may, in fact, be growing. While the application of spherical GP lenses on healthy eyes is decreasing as a result of advancements in specialty GP designs, GP lens use (including hybrids) in the United States has increased from 9 percent (Nichols, 2012) at the end of 2011 to 11 percent (Nichols, 2013) at the end of 2012. Internationally, the GP market remains steady, with 10 percent (Efron, 2013) to 12 percent (Morgan, 2013) of all contact lens patients worldwide fit into this modality. It is especially notable that renowned cornea and contact lens researcher Professor Nathan Efron—who has predicted the demise of GP lenses for the past 20 years—concluded in the former report that “rigid lenses will remain as a viable, albeit increasingly specialized, form of vision correction.”
The scleral lens market continues to demonstrate ongoing dramatic growth. It is apparent that some of this growth in scleral lenses is a result of their successful crossover from a modality limited mainly to irregular cornea and dry eye patients to one that also includes the correction of healthy eyes, notably astigmatic and presbyopic patients.
In addition, orthokeratology GP lenses, along with peripheral plus power soft lens designs, continue to demonstrate an effect on eye growth. These designs will continue to gain in popularity as their ability to induce myopic defocus, and therefore reduce myopia progression, is optimized.
GP multifocal lens designs continue to evolve with continuing introductions of higher add power aspheric designs, notably incorporating add power on the front lens surface.
|GP Trends in 2013 and Beyond*|
|In your opinion, what is the future of GP lenses in the next one to three years and what types of designs have the most potential to impact the contact lens marketplace?|
|Healthy eyes||8 (including 5 for multifocals)|
|* GP Lens Institute Advisory Committee (28 respondents with some providing more than one design)|
Figure 1. Irregular cornea prescribing habits of eyecare professionals who fit GP lenses.
The Scleral Lens Phenomenon
It is very evident that scleral lenses represent the greatest current area of growth in the GP market and possibly the greatest area of future growth. The benefit of initial comfort that rivals that of soft lenses, combined with the quality of vision provided by rigid lens optics, has made this modality one that laboratories and practitioners have increasingly embraced over the last six to seven years. When the GP Lens Institute (GPLI) Advisory Committee, comprised of experts in the area of fitting specialty contact lenses, was asked what the greatest advancement in GP lenses was in 2013, 89 percent indicated some form of scleral lenses. In addition, the Committee also offered the opinion that scleral lenses will continue to have the greatest potential impact on the GP prescribing habits of practitioners over the next three years (Table 1 and “Comments From the Experts” sidebars) while representing an important tool to benefit both patients and the contact lens practice.
Another indication of growth in the scleral lens category is the fact that numerous companies have recently introduced—or soon will introduce—new scleral lens designs (Table 2). Much of this growth appears to be the result of increased scleral lens education, resulting in increased practitioner use. As practitioners gain proficiency in fitting scleral lenses, they find this a viable modality for improving the lives of many irregular cornea patients who have experienced comfort, vision, and/or fitting-related problems with other contact lens modalities and were possibly facing surgery.
The Custom Lab Channel of Bausch + Lomb (B+L) recently conducted two surveys that revealed some very interesting findings pertaining to scleral lens trends. In one of the surveys, conducted during the last quarter of 2012, 365 eyecare professionals who fit GP lenses responded to questions pertaining to their lens usage in fitting irregular cornea patients. The results showed that 52 percent never fit scleral lenses (Figure 1), indicating that there is room for growth in scleral lens education. However, it was evident that responding practitioners who do fit scleral lenses believed that their scleral lens patients encountered fewer problems with comfort and wearing time compared to their corneal GP lens wearers (Figure 2). The second survey was sent to keratoconus patients accessed through the National Keratoconus Foundation, with a total of 970 respondents. The results showed that keratoconus patients fit with scleral lenses are more satisfied with both their vision and comfort than are those fit with corneal GP and hybrid lenses. The difference in comfort is especially notable (Figure 3).
Figure 2. Irregular cornea prescribing habits of eyecare professionals who fit GP lenses: Comfort and length of wearing time of GP corneal versus scleral lens wear.
Figure 3. Vision and comfort ratings with keratoconus patients wearing corneal GPs, scleral GP lenses, and hybrid lenses.
It is also evident that scleral lens use with healthy eyes, notably astigmatic and presbyopic patients, continues to increase. Woo (2013) reported on a multicenter clinical study under the direction of Dr. Langis Michaud that compared the comfort, vision, and wearing time of a scleral lens to a soft toric lens in a cross-over study involving astigmatic subjects. The results indicated that the comfort and wearing time were equal between the two groups; 19 of the 36 subjects completing the study preferred to stay in the scleral lens, and 75 percent of the subjects preferred the vision of the scleral lens.
Growth in the multifocal scleral lens market has been especially notable. There are, at minimum, 12 multifocal scleral lens designs from 11 manufacturers, with more due out in 2014. These designs can typically be fit on both healthy and irregular corneas. A list of most of the currently available GP scleral multifocal lens designs is available in the article “The Developing Role of Scleral Lenses in Today’s Society” by Melissa Barnett, OD, and Brooke Messer, OD, in this issue. New and forthcoming designs include:
Comments From the Experts, Part 1
What do you think the greatest advancement in GP lenses has been in 2013? What is the future of GP lenses in the next one to three years?
• Ron Watanabe, OD: “The biggest impact on the GP market will be from scleral lenses for ‘normal’ (non-diseased) corneas, multifocal scleral lenses, and corneal reshaping.”
• S. Barry Eiden, OD: “New scleral GP multifocal designs—these lenses perform so well due to the GP optics that are centered and stabilized with scleral lens fitting characteristics.”
• Tom Quinn, OD, MS: “No longer do patients need to choose between good vision (corneal GP lenses) and good comfort (soft lenses). Scleral lenses (including mini-scleral lenses) offer the optics of a GP lens with excellent comfort.”
• Bob Grohe, OD: “GP growth will be stable as post-refractive surgery patients who have presbyopia re-enter the contact lens arena seeking non-surgical vision options.”
• Arch Holcomb (ABB Optical Group/ABB Concise): “With advances in manufacturing and instrumentation, this (scleral lens) modality is growing in popularity due to its inherent comfort, which equals or exceeds that of soft lenses in most cases; its ability to vault all corneal irregularity while maintaining excellent corneal health; and its versatility in application. The GP industry has been battling the comfort issue since the advent of GP lenses, and scleral lenses provide an effective solution to the dilemma.”
• Bruce Anderson, OD: “I think that the excellent comfort of scleral lens designs, and their ability to correct large amounts of astigmatism and irregular corneas so well, will continue to grow this modality. My percentage of GP lens fits has increased due to the wonderful performance of these lens designs.”
• Craig Norman, FCLSA: “It feels as though there will be continued growth in the GP category. Sclerals are hot. Corneal reshaping is becoming more accepted and should significantly increase with positive safety data being released along with the potential for myopia control. New progressive GP multifocals are looking good, and sclerals may play a role in correcting presbyopia as well.”
• Mile Brujic, OD: “I think that we will continue to see an expansion of scleral lens options along with a growing body of knowledge and research to support their use.”
• Robert Davis, OD: “Patient expectations in a contact lens design include pristine vision, unprecedented comfort, and ultimate convenience. Large-diameter GP lenses, including mini-sclerals and hybrids, have the greatest potential to achieve these goals in the marketplace.”
• Keith Parker (AVT): “The comfort barrier of the GP lens continues to be overcome as designs and manufacturing processes combined with advanced material and compliance options improve.”
• Blanchard is launching its Onefit multifocal, which combines the small-diameter semi-scleral Onefit lens with the company’s proprietary anterior surface multifocal design. As with almost all of the scleral designs, it is a near-center design available in a low and high add power.
• Lens Dynamics has introduced a multifocal option for the Dyna Semi-Scleral lens with add powers up to +4.50D.
• Essilor has introduced the Jupiter Plus scleral multifocal lens. This is a center-distance lens design capable of add powers in the +1.50D to +1.75D range.
• Valley Contax has introduced the Custom Stable Near scleral lenses in both 15mm and 16mm diameters. This is a center-near design with the near zone size determined by pupil size and eye dominance.
• Advanced Vision Technologies (AVT) is expanding its center-distance AVT Scleral Multifocal to include a decentered optical axis option designed to provide usable optics in line with the visual axis.
• ABB Optical Group is currently developing a new custom lens for presbyopia that will combine the benefits of both alternating vision bifocal lenses and progressive, multifocal lenses, satisfying all three visual requirements (i.e., near, distance, and intermediate vision), according to the company.
New and Forthcoming Scleral Lens Designs
■ Paragon Vision Sciences has introduced two new scleral designs. In the fourth quarter of 2012, the company launched the NormalEyes 15.5 scleral lens. It offers the same technology used in Paragon CRT including the Dual Axis feature, which assists in centration and comfort in astigmatic patients. It is laser marked with lens parameters, plasma treated, and is available in the Paragon HDS 100 material. Paragon also purchased the rights to John Mountford’s ICD 16.5mm design, which was then modified by Patrick Caroline and Randy Kojima. This design offers a tangent angle periphery and an aspheric front surface. Domestic authorized manufacturing laboratories that produce this lens include ABB Concise, Essilor, and Valley Contax. It is available in two fitting set options: a 72-lens fitting set (36 lenses for ocular surface disease, 24 lenses for keratoconus, and 12 lenses for post-surgical, Figure 4), and a 21-lens fitting set (nine lenses for ocular surface disease, eight lenses for keratoconus, and four lenses for post-surgical).
Figure 4. The Paragon NormalEyes fitting set.
■ Visionary Optics has introduced the Europa Scleral lens, with noted scleral lens expert Dr. Greg DeNaeyer as a designer. A modified scleral zone and enlarged optical zone are designed to optimize scleral landing and improve corneal vault. This new design also incorporates a reverse geometry curve to fit a wider range of corneas while including options for front-surface toric, back toric haptics, and notching.
■ In January, Menicon announced the introduction of the Rose K2 XL (Blanchard/Art Optical, Figure 5), designed and developed by Dr. Paul Rose. It features a diameter range from 13.6mm to 15.6mm with a standard diameter of 14.6mm. Besides Menicon Z (Menicon), it is available in Tyro 97 (Lagado) and Boston XO (B+L) materials and follows the same simplified fitting approach as the other Rose K lens designs, with several of the same design features including an aspheric back optic zone that decreases as the base curve radius steepens, front-surface aberration control, and numerous edge lift options.
Figure 5. The Rose K2 XL on a post-graft patient.
■ X-Cel Contacts introduced its Atlantis Scleral lens at the 2013 GSLS meeting. It has an easy-to-fit 1,2,3 fitting philosophy with independent zone manipulation for best fit results. As with several of these scleral lens designs, a helpful webinar is available on X-Cel’s website (www.xcelcontacts.com/our-lenses/gasperm-atlantis).
■ Essilor continues to add expanded lens design features to its Jupiter line of scleral lenses. The company can manufacture this lens with front-surface toric powers, toric peripheral curves, up to 20.00D of reverse geometry, custom edge application, and custom notching.
■ Valley Contax continues to add to its Custom Stable series of scleral lens designs, which include the Custom Stable 15, the Custom Stable 16 (standard and reverse geometry), and the Custom Stable 18 (Figure 6).
Figure 6. The Custom Stable lens.
■ Ultralentes (Brazil) has launched two scleral lens designs (Scleral Bastos UC and UF) for the management of irregular cornea and dry eye disease. The Scleral Bastos UC has a double base curve plus haptic curve with diameters ranging from 18.5mm to 21.5mm.
Scleral Lens Challenges Of course, there are still questions to be answered about scleral lenses. How much “settling” (i.e., reduction in sagittal depth) occurs over time? Is optical coherence tomography (OCT) required for scleral evaluation? How can patients easily master handling of these large lenses?
Several studies are currently underway pertaining to the settling issue. It is essential for these designs to vault the cornea as lens-to-cornea bearing can result in mechanical debridement of the epithelium. At the 2013 Global Specialty Lens Symposium (GSLS) (Bennett, 2013) Patrick Caroline reported that scleral lenses settled an average of 96 microns over an eight-hour period; however, the lenses continued to settle to the point that an average of 146 microns of settling had occurred after one month.
At this same meeting, Dr. Michaud recommended an initial clearance of 300 microns to 350 microns for larger lenses (i.e., ≥15.5mm) and no greater than 200 microns for smaller lenses (i.e., 14mm to 15mm).
Careful slit lamp evaluation using an optic section can provide a good estimate of the amount of central clearance behind a scleral lens, negating the need for OCT. However, OCT is valuable in assessing the peripheral fit of a scleral lens for the possibility of a tight peripheral fit in which the edge of the lens becomes embedded in the conjunctiva, which may result in vessel blanching. As lens designs continue to improve, this may reduce the need for OCT testing.
Scleral lenses of larger diameters that must be completely filled with unpreserved filling solution can present handling challenges for some patients. Two new devices can help make scleral lens application easier. The EZi Scleral Lens Applicator (Figure 7) from Q-Case, Inc. (www.ezibyqcase.com) consists of a plastic ring-like device with a lens holder that makes a more stable platform for the lens to be held and applied. Woo (2012) reported that subjects found it significantly easier to apply a scleral lens using the EZi applicator compared to using a large suction cup or an o-ring. The innovative See Green Lens Inserter (Figure 8) from Dalsey Adaptives (www.dalseyadaptives.net) is ideal for patients who have unsteady hands or who need both hands to hold their lids open. The lens is positioned on a plunger that is positioned on a stand; patients then can bring their eye to the lens. The green LED light on the stand can help patients better visualize the lens and determine whether the lens is well centered on the stand.
To assist in the care of scleral lenses, in April Menicon America, Inc. received FDA clearance for the Progent Large Diameter Contact Lens Case, a nonvented, barrel-style case designed for deep cleaning large-diameter GP lenses (11mm to 23mm) in Menicon Progent.
As a non-preserved solution is required for scleral lens filling and application due to the possible toxic effects to the epithelium when in prolonged contact with a preserved solution, unpreserved tears and 3mL sterile 0.9% NaCl inhalation solutions are often used. Many companies are considering the development of their own filling solution with the increasing popularity of this modality.
Both overnight orthokeratology (OOK) and peripheral plus power soft lenses have been the focus of numerous studies for the purpose of determining how they can be optimized to slow down and possibly halt the progression of myopia. The significant importance of controlling myopia has been the focus of worldwide efforts by Cary Herzberg, OD, president of the Orthokeratology Academy of America and, in recent years, by Professor Brien Holden. At the 2013 GSLS, Professor Holden stated that the incidence of myopia should increase to 2.5 billion by the year 2020. In addition, the incidence in the United States alone is nearly 50 percent, with an eight-fold increase in individuals exhibiting ≥8.00D of myopia; therefore, the risk of both glaucoma and retinal pathology is greatly increased.
Following up on the pioneering work by Dr. Earl Smith at the University of Houston, Professor Holden discussed a unique peripheral plus power soft lens design that appears to significantly slow eye growth. He also reported that OOK appears to have the same effect, likely because the reverse geometry design converts relative hyperopia in the retinal periphery to relative myopia. This is consistent with several studies including most recently a study by Charm and Cho (2013) in which axial length elongation was 63 percent slower in children using OOK than in spectacle-corrected children.
It is also evident that OOK appears to improve a young person’s quality of life versus wearing spectacles. Santodomingo-Rubido and colleagues (2013) found that OOK-wearing young people had a higher perception of their overall vision, near vision, distance vision, appearance, ability to perform activities, academic performance, and peer perceptions compared to children wearing spectacles.
Paragon Vision Sciences (Paragon, www.paragoncrt.com) routinely surveys its Corneal Reshaping Treatment (CRT) certified practitioners. Some results of the company’s most recent survey (Scoggins, 2013) indicate that:
• 75 percent of new CRT patients are between the ages of 8 and 18.
• For 2013, 53 percent of the practitioners report that the number of new CRT fits in their practice is increasing, 42 percent staying the same, and 5 percent decreasing.
In 2014, Paragon will introduce two new designs. The Paragon CRT Mono-Axis design will feature a Landing Zone Angle (LZA) that is shallower, or deeper, in a single semi-meridian with a “transverse reconciliation” that is not limited to a specific quadrant. This design is intended to achieve lens centration on corneas that have measured topographic peripheral asymmetry. The Paragon CRT Emerging Myopia design will be recommended for patients exhibiting the earliest signs of myopia who desire the benefits of the corneal reshaping process with Paragon CRT, before their myopia advances.
B+L (www.bausch.com/en/ECP/Our-Products/Orthokeratology) continues to increase the number of lens designs approved for use with its Boston Equalens II lens material for Vision Shaping Treatment (VST). These include the following lenses:
• BE Retainer (various labs)
• CKR (Progressive Vision Technologies)
• Contex OK E-System (Contex)
• DreamLens (various labs)
• Emerald (Euclid Systems Corporation)
• NightMove (Gelflex, Advanced Corneal Engineering)
• MiracLens (MiracLens, LLC)
• Orthofocus (Progressive Vision Technologies)
• Super Bridge and E-Lens Overnight Orthokeratology Lens (E&E Optics)
• Vipok Inc. (E&E Optics)
• Wave Contact Lens System (Custom Craft Lens Service, Metro Optics, X-Cel Contacts)
Comments From the Experts, Part 2
How have GP lenses benefitted your practice and your patients?
• Jason Jedlicka, OD: “They have allowed me to offer a unique specialty and provide my patients with better vision. My patients tell their friends, so it grows my practice.”
• Ron Watanabe, OD: “GP lenses have made my practice a referral site for surrounding practices for difficult-tofit patients, including keratoconus and other irregular corneas, multifocals, and even custom soft lenses. GP options have helped my patients who have difficulty with spectacles or soft contact lenses and could not find an acceptable option previously.”
• Roxanna Potter, OD: “GP lenses continue to offer unparalleled vision and safety to contact lens patients, while at the same time maintaining profitability in practice.”
• Art Epstein, OD: “GP lenses have allowed me to help patients in ways that would otherwise have been impossible. They have given me the power to dramatically restore vision and to improve, if not transform, lives.”
• Greg DeNaeyer, OD: “GP lenses (corneal and scleral) restore vision for patients who have moderate-to-severe irregularity when all other options (including surgical) have failed. Scleral lenses are often the only successful management strategy for patients who have severe ocular surface disease.”
• Clarke Newman, OD: “Benefitted? They are the very lifeblood of my practice as a specialty prescriber.”
• Carmen Castellano, OD: “GPs provide patients with the highest quality vision and allow our practice to differentiate itself from others.”
• Ray Brill, OD: “GPs consistently allow us to offer customized vision and fitting when soft lenses fail to do so. Because we stock large inventories of GP lenses, we save chair time and can maximize first visit success. GP lenses differentiate our practice from the mainstream soft-lens-only practices.”
• LaMar Zigler, OD: “As specialists in all designs of contact lenses, we have created a ‘difficult to fit’ contact lens practice. With few practitioners willing to fit these designs, we have created a niche contact lens practice that compliments our primary care practice. We receive word-of-mouth referrals from satisfied patients as well as referrals from ODs and MDs and from our website for these specialty lenses and for routine contact lenses and exams.”
As with Paragon CRT, practitioners need to be certified to fit a particular VST lens design, but this certification can be accomplished easily via an online testing format.
New Multifocal Developments
In addition to the many scleral multifocal designs that have recently been introduced, manufacturers continue to introduce innovative corneal multifocal designs—typically with front-surface optics—that particularly benefit patients who have advanced presbyopia and those who have undergone refractive surgery.
Figure 7. The EZi Scleral Lens Applicator.
In late 2012, Art Optical introduced the CLASIKcn post-LASIK multifocal design for the increasing number of LASIK patients who now manifest moderate-to-advanced stages of presbyopia. With center-near multifocal optics, this lens can be fit from a trial set or from corneal topography. Art Optical will also be introducing two new presbyopic GP lens designs in the coming months. The first will be a center-distance aspheric simultaneous multifocal using front-surface technology that the company says encompasses multiple eccentric power zones to help maintain distance clarity while dramatically enhancing the near power effect. This design will be indicated for patients who have worn high-eccentricity back-surface multifocals and experienced the typical problems with corneal molding, and for those patients who have experienced poor near vision with other multifocal designs. The second design will be a center-near multifocal using an intralimbal diameter to stabilize lens centration and maintain a simultaneous power effect.
AVT has developed a modification of its Naturalens Progressive Multifocal to optimize mid-range computer/intermediate vision correction. The Naturalens Progressive MR (mid-range) will be available in GP corneal, scleral, and custom soft lens modalities.
ABB Concise is currently developing a new custom lens for presbyopia that the company says will combine the benefits of both alternating vision bifocal lenses and progressive multifocal lenses, satisfying all three visual requirements of presbyopes (near, distance, and intermediate vision).
Advances in manufacturing technology have resulted in the ability to make almost any lens design possible, which is invaluable for patients who have very irregular corneas. In recent years, the use of quadrant-specific designs has become increasingly popular. TruForm Optics recently introduced the TruPMD lens design. This is a quadrant-specific design with the top part of the lens made to fit the superior portion of a pellucid marginal degeneration (PMD) cornea and the bottom part of the lens made to fit the inferior portion of a PMD cornea.
There are an increasing number of resources available to help in managing the various types of GP-wearing patients. Perhaps the most important are the laboratory consultants who can help you with choosing a lens design, designing and fitting the lens, and troubleshooting. Any supplemental information that can be provided (i.e., photographs, video, topography maps, OCT images) can certainly help consultants troubleshoot particular patients. Every laboratory has several resources (i.e., fitting guides, PowerPoint presentations, calculators, etc.) to assist with their lens designs, and many offer webinars for practitioners to learn how to fit and troubleshoot a particular design.
Several organizations offer useful programs and resources. The Orthokeratology Academy of America (www.orthokacademy.com) will once again offer its “Vision by Design” meeting to be held April 24 to 27, 2014 in Chicago. The Scleral Lens Education Society (SLES) (www.sclerallens.org) provides scleral lens workshops as well as videos on care and handling of scleral lenses. The SLES Board is a “Who’s Who in Scleral Lenses,” including Drs. Bruce Baldwin, Jason Jedlicka, Muriel Schornack, Melissa Barnett, Eef van der Worp, Michael Lipson, Lynette Johns, and Christine Sindt, not to mention former board member and SLES Co-Founder Dr. Greg DeNaeyer. The GPLI (www.gpli.info) has a new userfriendly look to its web site, allowing easy access to resources pertaining to the following categories: 1) Spherical GP, 2) High Astigmatism, 3) Corneal Reshaping, 4) Keratoconus/Post-Surgical, 5) Multifocals, 6) Scleral Lenses, and 7) Custom Soft Lenses. An online GP curriculum has been created (under the “Educators” tab), a coding and billing module for specialty contact lenses has recently been introduced, and a “Laboratory Consultants FAQ” program will be introduced before the end of the year. In addition, webinars from experts in the field pertaining to specialty GP and custom soft lenses are held every month with continuing education approval possible.
Figure 8. The See-Green Lens Inserter.
It is evident that GP lens use is stable in today’s market, largely as a result of the impact that new scleral lens designs have recently exhibited—not only with dry eyes and irregular corneas, but also with astigmatic and presbyopic patients. In addition, the GP market has benefitted from the introduction of new and innovative multifocal designs, as well as the ongoing myopia research indicating that OOK can slow down axial length growth. These trends should continue not only through the remainder of 2013, but well into the future. CLS
GPLI Advisory Committee members: Bruce Anderson, OD; Mark André, FCLSA; Richard Baker, OD; Jim Boucher, OD; Ray Brill, OD; Mile Brujic, OD; Karen Carrasquillo, OD, PhD; Carmen Castellano, OD; Robert Davis, OD; Greg DeNaeyer, OD; Barry Eiden, OD; Art Epstein, OD; Bob Grohe, OD; Steve Harney, OD; Jason Jedlicka, OD; Michael Lipson, OD; Derek Louie, OD; Clarke Newman, OD; Craig Norman, FCLSA; Roxanna Potter, OD; Miles Press, OD; Tom Quinn, OD, MS; Cheri Vincent-Riemer, OD; Michael Ward, MMSc; Ron Watanabe, OD; Frank Weinstock, MD; Eric White, OD; and LaMar Zigler, OD.
Contact Lens Manufacturers Association Representatives: Josh Adams (Valley Contax), Luciano Bastos (Ultralentes), David Bland (Bausch + Lomb), Lee Buffalo (Blanchard Contact Lens), Ken Crawford (TruForm Optics), Linda Glover (X-Cel Contacts), Arch Holcomb (ABB Concise), Mike Johnson (Art Optical), Mary Ann Kail and Gary Richardson (Essilor), Greg Kline, Ken Kopp, and Pam Scoggins (Paragon Vision Sciences), Eric Marshall (Visionary Optics), Keith Parker (Advanced Vision Technologies), David Rusch (Firestone Optics), and Randall Sakamoto, OD (Menicon).
For references, please visit www.clspectrum.com/references.asp and click on document #215.