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It was noted in the news this week that the Manchester (England) airport was closed for four hours due to a bomb scare associated with a contact lens care solution. In the United States, the Transportation Security Administration (TSA) restricts the carry-on of liquids in containers greater than 3 ounces. It is important to point out that multipurpose contact lens care solutions are considered "over-the-counter medications" by the TSA, and larger quantities can be carried on the airplane. However, these larger-sized bottles must be declared to the TSA. Please keep this in mind when talking to your patients about summer travel plans.
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Well known contact lens pioneer Professor Brien Holden joins the April 17th episode of the Power Hour, optometry's only live talk radio show. Professor Holden will discuss myopia control contact lenses, new developments in the contact lens arena, multifocal lenses and give his world view on contact lens usage. He'll also give his thoughts to the question, "Why haven't we made contact lenses perfect yet?"
The Power Hour, hosted by Dr. Gary Gerber, airs every Wednesday night at 9 p.m. ET. More information is available at www.powerpractice.com
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The Bausch + Lomb Boston products group has launched a new website that provides educational resources on how to fit GP lenses.
The growth in specialty lens designs such as scleral lenses for irregular corneas, as well as multifocal designs for presbyopes, has increased the need for education on these subjects. www.fit-boston.com provides links to valuable educational guides such as "A Guide to Scleral Lens Fitting" by Eef van der Worp and "Correction of Keratoconus with GP Lenses" from the University of Waterloo. Fitters can now access these guides, in multiple languages, instantly from links on the new website. Printed guides are still available through authorized Boston Laboratories.
For more information about Boston GP lenses and the guides, visit www.fit-boston.com
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Acculens recently announced the release of its newest scleral lens, Maxim 15.4mm. The Maxim 15.4 is indicated for patients who may require a smaller scleral design due to reasons such as fissure size, small corneal diameters and emerging to moderate modalities such as pellucid or moderate keratoconus. The Maxim Scleral lens is indicated for the management of corneal distortion and dry eyes. It is available in custom parameters manufactured in Boston XO-2.
Thirty lens trial lens sets are available free of charge. For more information contact Acculens at 1-800-525-2470 or visit acculens.com.
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Dailies Total 1 lenses (Alcon) made their debut in the United Kingdom last week. The water gradient lens is already available in other countries in Europe with a U.S. launch expected later this year.
According to Alcon, at the core, the lenses have a water content of 33%, which allows high oxygen transmissibility, with a Dk/t of 156 (Dk/t @ -3.00D). Between the core and surface, the water content changes from 33% to more than 80%. At the surface, the lenses have a water content of more than 80%.
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Piggy-Back Lens System
By Augusto Rosse, IACLE, Santiago, Chile |
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 The image shows a piggy-back system (the lens has a cut off where the GP lens rests centered), over a secondary ectasia. A special fluorescein for soft contact lenses was used.
We thank Augusto Rosse for this image 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.
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Scleral Lens Options: A Minority View
Jan P. G. Bergmanson, OD, PhD, PhD hc, DSc, FCOptom, FAAO
Texas Eye Research and Technology Center, University of Houston College of Optometry |
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A recent opinion poll conducted by Contact Lenses Today revealed that 90% of contact lens practitioners consider a miniscleral lens (15mm–17.9mm) before a full sized scleral contact lens (18mm–24mm). Our natural instinct is to regard a smaller lens as a smaller foreign body and, therefore, a healthier choice. However, this thinking ignores physics and physiology.
The physical size of the cornea is 11.7 x 10.6mm1 and allowing 1mm and a bit for the limbus we need a lens vaulting over the cornea to be at least 13mm in diameter in that central zone. If the overall diameter (OAD) of the lens is 16mm, the lens has 1.5mm on each side to land. That is to force an abrupt landing, which is likely to be uncomfortable and lead to vascular blanching. However, an 18mm lens will give you 2.5mm on each side to approach the conjunctiva far more gently and, in addition, spread the weight of the lens over a much broader area. This just has to be a more comfortable option!
Add to this fact the distribution of sensory nerve endings—the further from the cornea the fewer the nerve terminals. It follows that a lens design that settles and places its weight a little further away from the corneal perimeter will stimulate fewer sensory nerve endings and, for this reason, will be more comfortable. This paradox of bigger is better and more comfortable applies not only in Texas! It never stopped amazing me how much more comfortable the scleral contact lens is than a corneal GP, which is centered on the part of the cornea with the highest density of nerve terminals and, indeed, the most sensitive part of the body1. The same principles apply to the racing bike saddle—the biker puts all his weight on that tiny seat, which squeezes a very sensitive area. In contrast, the scleral lens is more like your favorite easy chair, where you can spread your weight over a larger area and suffer no uncomfortable, localized squeezing of sensitive anatomy.
This is just a minority view but you might just consider its advantages of the larger scleral option, especially for your patients!
Bergmanson JPG Clinical Ocular Anatomy and Physiology 20th Edition, Texas Eye Research and Technology Center, Houston, Texas, pp 80 – 111, 2013.
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The Passing of a True Contact Lens Leader and Visionary
Edward S. Bennett, OD, MSEd, FAAO
University of Missouri-St. Louis College of Optometry
Stanley J. Yamane, OD
Honolulu, HI |
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On March 20th the contact lens industry lost yet another pioneer with the passing of Sheldon Wechsler, OD, FAAO. Dr. Wechsler's influence impacted students, practitioners and, ultimately—through one of the greatest innovations in contact lens history—millions of patients.
After 20 years in private practice in California, Dr. Wechsler turned to education and was a full-time or adjunct faculty member at the University of Houston College of Optometry, University of Alabama at Birmingham School of Optometry, University of California-Berkeley School of Optometry, and Southern California College of Optometry. However, Dr. Wechsler's legacy will always be what started as a "secret project" that he initiated for a relatively small contact lens laboratory that had been purchased by a large healthcare company that would later be named Vistakon. The "secret project" would revolutionize the lens world: disposable soft contact lenses.
Dr. Wechsler was a great educator, leader, and visionary. It took a special individual to convince a skeptical public that a new technology, allowing contact lenses to be provided in a six pack form and disposed of regularly, resulting in healthier eyes and more consistent vision quality, would potentially all but eliminate single soft lens prescribing and packaging. He sold a revolutionary concept that forever changed the industry and, as a result, his legacy will live on well into the future.
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What To Do When You Need Miraflow
As many of us know, Miraflow was discontinued by CIBA Vision in January 2010. It was a potent daily cleaner whose main ingredient was isopropyl alcohol. Due to its ability to emulsify lipids and remove some mucin, it provided a thorough cleaning and as a result a loyal following. Frequently, both practitioners and patients ask me how they can obtain a similar cleaner. At the moment, there are at least three similar alternatives on the market. They include:
- Sereine Extra-Strength Daily Cleaner (Optikem International)*+
- Walgreens Extra Strength Daily Cleaner (Optikem International)*
- Lens Fresh (Orion Vision Group, formerly Marietta)#
*same formulations
+currently not available online; only by phone and in some independent pharmacies
#currently not available online or in stores; only by phone
It should be noted that there was a similar CVS brand, but it was discontinued in 2011. Also, CIBA Vision (now Alcon) has indicated that it did not sell the Miraflow formulation to these other laboratories, nor do they produce it for them as private label ("generic"). There is also no data on whether these formulations have the same or similar efficacy profile as Miraflow. However, if the customer reviews on the Walgreens website (see link below) are any indication, these products work well – and have filled a very necessary void.
http://www.walgreens.com/store/c/walgreens-extra-strength-daily-contact-lens-cleaner/ID=prod6039573-product?utm_campaign=bazaarvoice&utm_medium=SearchVoice&utm_source=RatingsAndReviews&utm_content=Default
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OCULAR SURFACE UPDATE
Katherine M. Mastrota, MS, OD, FAAO |
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Tear Film Osmolarity in Epiphora
An interesting late 2012 study conducted in the United Kingdom examined whether patients complaining of epiphora had tears of lower osmolarity. This 39-patient study divided patients into two groups. The first group included patients whose primary complaint was of epiphora due to either punctal stenosis, nasolacrimal duct obstruction (partial or complete), or eyelid laxity (without evidence of frank ectropion or entropion). The control group consisted of the second eye of some of the above patients, or those attending the clinic for other oculoplastic procedures not related to epiphora. Testing of tear osmolarity was performed using the TearLab osmometer. Patients with epiphora had a mean tear osmolarity of 291.8 mOsms/l compared with the control group mean of 303.7 mOsms/l. This difference was found to be statistically significant. The authors of this study conclude that patients complaining of epiphora in the absence of other ocular surface pathology have a significantly lower tear osmolarity.
Saleh GM, Hussain B, Woodruff SA, Sharma A, Litwin AS. Tear film osmolarity in epiphora. Ophthal Plast Reconstr Surg. 2012 Sep-Oct;28(5):338-40
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Influence of Decorative Lenses on Higher-Order Wavefront Aberrations
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This study aims to investigate the influence of decorative lenses on ocular wavefront aberrations.
A wavefront analyzer was used to measure higher-order aberrations (HOAs) in 20 right eyes of 20 participants while they were wearing Vistakon contact lenses of different designs: clear 1-day Acuvue, ring-design circle 1-day Acuvue Define (Accent style), or spoke-design circle 1-day Acuvue Define (Vivid style). All of these lenses are made of the same materials and have the same lens parameters, except for the tinted design. HOAs induced by each contact lens were measured for 4mm and 6mm pupils. The coma-like, spherical-like, and total HOAs of each lens type were compared. HOAs of well- and poorly fitting lenses were also compared.
For a 4mm pupil, the HOAs of the three lens types did not differ significantly. For the 6mm pupil, coma-like and total HOAs were significantly larger with decorative lenses than with clear lenses (P < 0.05, Bonferroni test). No significant differences were observed between the two decorative lens types. Poorly fitting decorative lenses showed significantly larger HOAs than did well-fitting decorative lenses.
The researchers concluded that poorly fitting decorative lenses may reduce the quality of vision, and that practitioners should take care to ensure that these lenses are properly centered.
Takabayashi N, Hiraoka T, Kiuchi T, Oshika T. Influence of decorative lenses on higher-order wavefront aberrations. Japanese Journal of Ophthalmology 2013.
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