Although increasing, the frequency of daily disposable lens fitting in North American markets is low compared with many other regions in the world. This is often recognized as an anomaly by practitioners in other markets, many of whom benchmark against North American clinical practices. We have done Quick Polls as to the primary reasons why practitioners do not fit more daily disposables, and the most cited reason is "cost."
In an interesting analysis, Efron and colleagues determined the relation between the proportion of daily disposable lens fits of 40 global markets and the gross domestic product (GDP) at purchasing power parity per capita for each market for 2011. The analysis showed a strong relation between the two—essentially, markets with higher daily disposable fits also generally have higher average wealth with a major exception—the United States (U.S.) market. The U.S. was in the top five in terms of markets with the highest average wealth, but was ranked 29th out of the 40 nations in terms of the proportion of daily disposable fits. This begs the question—what makes the US market different in terms of this issue as clearly our patients should be able to afford the daily disposable modality?
Efron N, Morgan PB, Woods CA. An international survey of daily disposable contact lens prescribing. Clin Exp Optom: Journal of the Australian Optometrical Assoc. 2012 Jul 31.
Prevent Blindness America has chosen Jim Mazzo, Senior Vice President, Abbott, and President, Abbott Medical Optics, as the recipient of its 2013 Person of Vision Award. The award will be presented to Mazzo at the PBA Person of Vision Dinner on February 2, 2013 in Newport Beach, CA.
The PBA Person of Vision Award recognizes an individual or corporation for outstanding leadership and dedication in the field of vision and eye health. Mazzo is being recognized by PBA for his career accomplishments and leadership in the eye health and eyecare industry, which includes senior executive-level positions at both AMO and Allergan. He has committed personal time to education, serving on several university boards as well as supporting other non-profits including Prevent Blindness America, the University of California, Irvine and the Gavin Herbert Eye Institute.
Abbott Medical Optics Inc. and Allergan Inc. will serve as the gold sponsors for the event. All proceeds from the event will go to support the sight-saving programs from Prevent Blindness America.
Sam Loshaek, who in his career worked for Wesley-Jessen Corporation and Borden Chemical, and held at least 40 patents, died November 7 at his home in Florida. He was 88.
Loshaek received a bachelor's degree in chemical engineering and a master's in organic chemistry from the University of Alberta in Edmonton. He earned his PhD in physical chemistry at the University of Wisconsin-Madison. Loshaek was later recruited by Wesley-Jessen to head Research and Development. It was there that he and his team developed natural looking eye color changing contact lenses. Unlike prior tinted lenses, these lenses closely resembled the variations in the iris for a more natural look. The lenses positioned WJ for significant growth and a stronger position in the market.
Plan Now to Attend GSLS 2013 in January
Plan now to attend the Global Specialty Lens Symposium January 24-27, 2013, at the Rio All Suites Hotel and Casino, Las Vegas, Nevada. With an expert international faculty and a CE-accredited agenda, the 2013 GSLS will include a fundamentals pre-conference, insightful presentations by experts in the field, hands-on demonstrations of cutting-edge products, as well as scientific papers and posters and networking opportunities with your colleagues from over 30 different countries.
Look for more detailed information in future issues of Contact Lens Spectrum and online at www.GSLSymposium.com.
C&E Vision Services, an industry buying group, has announced its January 2013 COPE approved Ocular Symposium highlighting Glaucoma. The seminar will be held on January 18th at the Doubletree Hotel in Orange California. Courses include, The Role of Imaging in Building Your Glaucoma Practice, Progression in Glaucoma, A Guide to the Clinical Management of Glaucoma and Secondary Glaucoma. More information about the January 18, 2013 seminar can be found at www.cevision.com/seminars/details/.
C&E conducted three symposiums in 2012 with nearly 1,400 doctors attending. The company's 2013 Ocular Symposium program will again provide 24 hours of COPE approved medically based education.
Improperly Inserted Mini-Scleral Lens By Edgar Davila-Garcia, OD, FIACLE, NCLE-AC, Bayamon, PR
This is the photo of a keratoconus patient wearing a mini-scleral lens. The lens was inserted without filling the bowl properly with saline solution and displays a big bubble. The patient inserted the lens in the morning and came to the office complaining of discomfort and blurry vision. Retraining on insertion and removal followed after the incident.
We thank Dr. Davila-Garcia for his photo and welcome photo submissions from our other readers! It is easy to submit a photo for consideration for publishing in Contact Lenses Today. Simply visit http://www.cltoday.com/upload/upload.aspx to upload your image. Please include an explanation of the photo and your full name, degree or title and city/state/country. ^ Back to top
RESEARCH REVIEW Loretta B. Szczotka-Flynn, OD, PhD, MS, FAAO
Contact Lenses in the Reduction of Ocular Allergy
Contact lenses are usually associated with ocular allergy, but two recent papers report on how contact lenses can play a role in the reduction of such allergies.
Wolffsohn and Emberlin1 examined the potential barrier and lubricating effects of modern daily disposable contact lenses (DD) against airborne antigens in 10 patients with confirmed sensitivity to grass pollen. They simulated a "very high pollen count day" in an exposure chamber with and without use of a daily disposable lens. Symptoms and clinical signs such as limbal and bulbar hyperemia and corneal and conjunctival staining were significantly reduced by lens wear.
They conclude that daily disposable contact lenses offer a barrier to airborne antigens which is enhanced by modern lenses with enhanced lubricating agents.
Alternatively, Soluri et al2 investigated the uptake and delivery of the anti-allergy drug ketotifen fumarate (KF) by 14 different commercially available contact lenses. They found that all the lenses studied demonstrated significant uptake and release of KF while lenses with charged surfaces demonstrated the greatest uptake and release. In fact, the majority of lenses were able to match or exceed the total amount of KF commonly administered to the eye using twice-daily dosing of commercially available (0.025%) eye drop formulations.
Although an anti-allergy drug-eluting lens is not commercially available, existing lenses have demonstrated the ability to release a clinically relevant amount of KF therefore a KF-contact lens delivery system in a daily wear scenario may be feasible. Additionally, the "vehicle-contact lens" itself may reduce ocular allergy in a barrier fashion.
1. Wolffsohn JS, Emberlin JC. Role of contact lenses in relieving ocular allergy. Cont Lens Anterior Eye. 2011 Aug;34(4):169-72. Epub 2011 May 6.
2. Soluri A, Hui A, Jones L. Delivery of ketotifen fumarate by commercial contact lens materials. Optom Vis Sci. 2012 Aug;89(8):1140-9. ^ Back to top
MATERIALS & DESIGNS Ronald K. Watanabe, OD, FAAO
GP Button Size Does Matter
In light of a recent article that predicted oxygen availability through scleral lenses (Michaud et al, 2012), it is important to think more about the materials we use when fitting these large diameter designs. It is important to note that not every material is available in large button sizes needed to cut out these large lenses, and not every material with large buttons can be made in every diameter. For example, the Menicon Z button is 16.5 mm in diameter and can be used for lenses up to 16.0 mm, but if you are fitting an 18.0 mm design, you will have to use a different material.
There are several great high Dk materials available in large button sizes. Amongst others, Menicon's Tyro-97 buttons are available in diameters up to 25 mm, Contamac's Optimum Extra buttons and Bausch + Lomb's Boston XO / XO2 buttons are available up to 21 mm, and Paragon's HDS-100 buttons are available up to 17 mm. With all these great choices, we are able to fit our scleral lens patients with the best lens materials for their individual needs.
Michaud L, van der Worp E, Brazeau D, et al. Predicting estimates of oxygen transmissibility for scleral lenses. Cont Lens Ant Eye. 2012 Dec; 35(6): 266-271. ^ Back to top
The Epidemiology of Microbial Keratitis with Silicone Hydrogel Contact Lenses
It was widely anticipated that after the introduction of silicone hydrogel lenses, the risk of microbial keratitis would be lower than with hydrogel lenses because of the reduction in hypoxic effects on the corneal epithelium. Large-scale epidemiological studies have confirmed that the absolute and relative risk of microbial keratitis is unchanged with overnight use of silicone hydrogel materials.
The key findings include the following: (1) The risk of infection with 30 nights of silicone hydrogel use is equivalent to 6 nights of hydrogel extended wear; (2) Occasional overnight lens use is associated with a greater risk than daily lens use; (3) The rate of vision loss due to corneal infection with silicone hydrogel contact lenses is similar to that seen in hydrogel lenses; (4) The spectrum of causative organisms is similar to that seen in hydrogel lenses, and the material type does not impact the corneal location of presumed microbial keratitis; and (5) Modifiable risk factors for infection include overnight lens use, the degree of exposure, failing to wash hands before lens handling, and storage case hygiene practice.
The lack of change in the absolute risk of disease would suggest that exposure to large number of pathogenic organisms can overcome any advantages obtained from eliminating the hypoxic effects of contact lenses. Epidemiological studies remain important in the assessment of new materials and modalities. Consideration of an early adopter effect with studies involving new materials and modalities and further investigation of the impact of second-generation silicone hydrogel materials is warranted.
Stapleton F, Keay L, Edwards K, Holden B. The Epidemiology of Microbial Keratitis With Silicone Hydrogel Contact Lenses. Eye Contact Lens. 2012 Nov 20. [Epub ahead of print] ^ Back to top