In a recent abstract in Contact Lens and Anterior Eye¹ Professor Nathan Efron humors us with his obituary to rigid contact lenses. I find his debates on this topic and recent eulogies for rigid contact lenses entertaining. He states that gas permeable (GP) lenses have dropped from comprising 100% of fits in the 1960's to 2% of new fits in the U.K. today. He offers 10 reasons for the demise of rigid lens fitting including arguments such as initial rigid lens discomfort, superior soft lens fitting logistics, and improved soft toric and bifocal/varifocal lenses, among others.

Personally, I have to disagree with Professor Efron. Gas permeable lenses comprise more than 50% of my clinical, hospital based, practice, and I know others where this percent is much higher. Even if we remove all the irregular cornea needs, GPs provide superior presbyopic lens options and improved optics for high corneal astigmats.²

Gas permeable lenses continue to provide the safest method of vision correction with contact lenses. According to a 2008 study in the U.K., GP lenses reduce the risk of microbial keratitis by 84% (0.16X , p<0.001) compared to programmed replacement soft lenses.³ Additionally, in a large population bases study in Australia, GP lenses had the lowest risk of microbial keratitis compared to ANY other lens type. Daily wear GP lenses had an annualized incidence of microbial keratitis of only 1.2 per 10,000 wearers.⁴ I certainly hope GP lenses don't die a slow death anytime soon!

References:
1. Efron N. Obituary-Rigid contact lenses. Cont Lens Anterior Eye. 2010 Jul 29. [Epub ahead of print],
2. Michaud L, Barriault C, Dionne A, Karwatsky P. Empirical fitting of soft or rigid gas-permeable contact lenses for the correction of moderate to severe refractive astigmatism: A comparative study. Optometry 2009;80:375-383.
3. Dart JK, Radford CF, Minassian D, Verma S, Stapleton F. Risk factors for microbial keratitis with contemporary contact lenses: a case-control study. Ophthalmology. 2008 Oct;115(10):1647-54, 1654.e1-3. Epub 2008 Jul 2.
4. Stapleton F, Keay L, Edwards K, Naduvilath T, Dart JK, Brian G, Holden BA. The incidence of contact lens-related microbial keratitis in Australia. Ophthalmology. 2008 Oct;115(10):1655-62. Epub 2008 Jun 5.

The September issue of Contact Lens Spectrum features an article by Tim Koch on Definitive (Contamac), a new latheable silicone hydrogel material (http://www.clspectrum.com/
article.aspx?article=104631). Unlike most currently available silicone hydrogel materials, this one can be lathe-cut into any soft lens design.The only other available latheable silicone hydrogel material is the O2Optix Custom (Ciba Vision), which debuted in 2006. The O2Optix Custom lens is a great option for high myopes, high hyperopes and aphakes, having a power range of +20.00 to -20.00 D (and 14 base curve / diameter combinations), but it is only available in spherical powers. It has 32% water content, Dk of 82, modulus of 1.1 MPa, and is recommended for quarterly replacement.

By comparison, Definitive has 74% water content, Dk of 60, and modulus of 0.39 MPa. It has recently undergone clinical trials for FDA approval and should be available soon through authorized laboratories. Labs should be able to produce the Definitive material in virtually any design, including options for torics, multifocals, and keratoconus. This means that there will now be another silicone hydrogel option for patients with extreme refractive needs who also benefit from high oxygen transmissibility. Keep your eyes open for this great new material option in the weeks to come.

Reference:
Koch TO. A New Era of Specialty Soft Contact Lens Fitting. Contact Lens Spectrum. 2010 Sept.

Blanchard Improves MSD Lens Design Options

Blanchard has expanded the design options available for its MSD (mini scleral design) lenses to provide an effective and versatile design for eyes with highly irregular corneas, traumatic injury, and ocular surface disease (OSD).

Per the company, new edge clearance options of 1 Flat and 2 Flat provide control for peripheral seal off, blanching, and vessel engorgement (18.0mm Edge Clearance standard 1-Flat only). In addition, a new midperipheral/limbal clearance zone value aids when fitting extremely steep corneas where greater sagittal depth values are required. The MSD lenses are now available in 15.8mm and 18.0mm diameter, with sag depth values ranging from 3.60mm to 5.80mm (0.10mm/100 micron increments) with four midperipheral/limbal zone clearance values (Decreased-Standard-Increased-Double Increased) in any lens power.

The newly revamped fitting set contains 30 lenses, 10 sag depth values ranging from 3.80mm to 5.60mm in 0.20mm increments (200 microns), each having three midperipheral/limbal zone clearance values (Increased-Decreased-Standard). This allows the fitter to use the set on a broader range of conditions without the need to purchase an additional fitting set. Fitting sets and all MSD lenses are available fenestrated and non-fenestrated.

For more information visit www.blanchardlab.com, or call 800-367-4009.

SynergEyes Launches Website for Patients with Keratoconus

SynergEyes, Inc. has launched a new educational website, www.treatkeratoconus.com, for patients seeking information and treatment options for keratoconus.

The website includes a blog with articles written by doctors who specialize in treating keratoconus as well as detailed information on a new program created to provide hybrid contact lenses to selected patients free of charge. This new program is called the Sharing Vision Grant Program and is sponsored by SynergEyes, Inc.

TreatKeratoconus.com also has several informative sections including Common Questions, Treatment Options, Hybrid Contact Lens Technology and an interactive section called "Ask an Expert." Patients submit questions about their eye disease to a nationally recognized panel of doctors and specialists and answers are posted on the website so other patients can benefit from the knowledge.

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Alcon Update on Exploratory Lens Care Solution

At the Association for Research and Vision in Ophthalmology annual meeting, Alcon presented data on a new wetting agent—a synthetic block copolymer that uses proprietary polymer chemistry, EOBO, poly (oxyethylene)-poly (oxybutylene). The poster presentation indicated that a test solution containing EOBO reduced the surface and bulk hydrophobicity and improved the hydrophilic properties of silicone hydrogels as compared to a saline solution control. Alcon is developing this technology specifically for silicone hydrogels for possible future use in its lens care product line.

Global Specialty Lens Symposium, January 27-30, 2011, Paris Hotel & Casino in Las Vegas

Plan now to attend the Global Specialty Lens Symposium in January 2011. With an expert international faculty and a CE-accredited agenda, the 2011 GSLS will include insightful presentations by experts in the field, hands-on demonstrations of cutting-edge products as well as scientific papers and posters. Look for more detailed information in future issues of Contact Lens Spectrum and online at www.GSLSymposium.com.
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Alcon Launches TobraDex ST Suspension

Alcon announced the launch of its new combination anti-inflammatory/anti-infective product, TobraDex ST suspension, in the U.S. TobraDex ST (tobramycin/dexmethasone ophthalmic suspension) 0.3/0.05% is indicated for steroid-responsive inflammatory ocular conditions for which a corticosteroid is indicated and where bacterial infection or risk for infection exists.

"This product was specifically designed to increase retention time on the eye, allowing the drug to calm inflammation and fight bacteria effectively," said Stuart Raetzman, Vice President, Global Marketing and Area President for the U.S. "Clinical studies indicated that 10 minutes after dosing, concentrations of TobraDex ST remained on the ocular surface at levels high enough to kill 99.9% of ocular bacteria."

According to the company, TobraDex ST suspension is designed with stable suspension properties that prevent settling, thereby ensuring the desired amount of dexamethasone delivery. It is formulated with low viscosity in the bottle allowing for easier dispensing. The company further states that these two factors contribute to making this an ideal treatment for eye conditions where both infection and inflammation exist, like acute blepharitis or bacterial conjunctivitis.

CIBA Launches Education Campaign around World Sight Day

CIBA Vision (CIBA) is encouraging people worldwide to have their eyes examined during the month of October, in celebration of World Sight Day on October 14. World Sight Day is the main advocacy event for "VISION 2020: The Right to Sight," a global effort to raise public awareness about blindness and vision impairment as well as to educate individuals about healthy vision. World Sight Day is coordinated by the International Agency for the Prevention of Blindness.

To create greater appreciation for healthy vision and illustrate the effects of visual impairment, CIBA has created a campaign showing famous landmarks as they might be viewed through the eyes of an individual with uncorrected refractive errors. Through a series of photographic images ranging from the Eiffel Tower and Statue of Liberty to Mount Fuji and Victoria Harbor, consumers can see how astigmatism, myopia, hyperopia and presbyopia impact sight.

Beginning October 14, consumers will be able to view the online image gallery at www.cibavision.com, or on posters and postcards available at participating eye care professional offices. Additionally, a two-minute video focused on the gift of sight and the need to protect one's vision has been produced for online consumer education and for use in ECP offices.

CIBA is also the Founding Corporate Sponsor of Optometry Giving Sight which coordinates the World Sight Day Challenge, a fundraising campaign that encourages optometrists to make a donation online or pledge their eye exam fees from one day from September 1 – October 14. Visit www.givingsight.org for information.

It is important that we all stay current in our field, and there are many ways to do this. One way is through some of the excellent meetings that take place each year. I've listed some potential meetings of interest in the United States, and one meeting that I'd particularly like to highlight is our meeting – The Global Specialty Lens Symposium. Stay tuned for more coverage of the Global Specialty Lens Symposium, with a meeting recap in Contact Lens Spectrum later in 2011.

2010
CLMA - Sept. 30-Oct. 2, Tempe, AZ
Vision Expo West - Oct. 6-9, Las Vegas, NV
East-West Eye Conference - Oct. 7-10, Cleveland, OH
AAO (ophthalmology) - Oct. 16-19, Chicago, IL
Orthokeratology Academy of America - Oct. 20-24, Oak Brook, IL
Optometric Management Symposium - Nov. 5-7, Orlando, FL
AAO (optometry) - Nov. 17-20, San Francisco, CA

2011
Global Specialty Lens Symposium - Jan. 28-31, Las Vegas, NV

In last week's issue, the link to Dr. Gromacki's article on the H2O2 solution lens cleaning technique which includes a digital rubbing step was not functioning correctly. Please click here to view the article, A New Method for Cleaning Soft Contact Lenses, in the April 2008 Contact Lens Spectrum or visit the Contact Lens Spectrum archives.

Pinguecula and Contact Lenses

These researchers wanted to assess the relationship between age and the incidence and severity (determined by a grading system) of pinguecula in contact lens (CL) wearers, and to compare the grade of pinguecula between CL wearers and non-wearers.

A total of 600 CL wearers (94 wore hard CLs (HCLs) and 506 wore soft CLs (SCLs)) aged 11-60 years and 579 non-wearers aged 10-60 years were enrolled. The age, gender, medical history, ocular history, and grade of pinguecula at two locations (nasal and temporal) were determined in all subjects.

There was an age-related increase in the grade of pinguecula among both CL wearers and non-wearers. The grade of pinguecula at the temporal conjunctiva was higher in CL wearers than in non-wearers (P=0.01907), whereas it was higher in HCL wearers than SCL wearers at both the nasal and temporal conjunctiva (P<0.00001 and P<0.00001).

This was the first assessment of the severity of pinguecula in a large consecutive series of CL wearers. The researchers concluded that their results suggest that the use of CLs is an important risk factor for pinguecula.

Mimura T, Usui T, Mori M, Yamamoto H, Obata H, Yamagami S, et al. Pinguecula and contact lenses. Eye (Lond). 2010 Sep 10.