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International Newsletter and Forum on Rigid Gas Permeable Contact Lenses, Corneal Shape, Health and Vision |
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Petit Lentille
 At a recent, really nice optometry and contact lens meeting in Paris (FR), the term 'petit lentille' was used from the podium on the topic of (R)GPs. It's funny how we now refer to 'small diameter' (R)GPs as opposed to the large diameter lenses of which we have seen such a surge lately, thanks in part to some visionary icons (see GSLS award of excellence item). I-site newsletter continues to cover both, as I think that both lenses have their place in contact lens practice. But - granted - the attention for sclerals is overwhelming, partly because there is still much to learn. One of the unanswered questions still is 'the oxygen thing.' A brand new publication by Jaynes, Edrington and Weissman in Contact Lens & Anterior Eye suggests that clinicians would be prudent to prescribe scleral lenses manufactured in the highest-Dk materials available and to fit without excessive corneal clearance to minimize anterior segment hypoxia. This is based on a spreadsheet model, and previous predictions were on models as well. Although models predict that it may be difficult to achieve a scleral lens/tear system combination to prevent corneal hypoxia, it appears that there is a discrepancy between what is seen in clinical practice and what the models predict, as recalled earlier in this newsletters' column 'Going Blanc.' But until we know more, the above seems to be the best advice to follow. And if in doubt or if it's critical: 'petit lentille' (R)GPs always provide the best oxygen delivery to the cornea of the two. |
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Review
Muriel Schornack provides a comprehensive review article in Eye & Contact Lens on sclerals. One of the interesting remarks she makes is: 'a cursory search of the term "scleral lens" in the archives of Contact Lens Spectrum, a widely
distributed monthly publication that focuses on developments in the contact lens industry, yielded 262 related articles and case reports dating back to 1994.' Interestingly, nearly 200 of these have been published since 2010. Other key quotes from the review article are: 'For patients with few other options for disease management, we can be reasonably confident that the risks of inaction or surgical intervention outweigh potential risks of scleral lens wear, but the exact placement of scleral lenses within an overall management strategy has yet to be defined. Despite unanswered questions regarding scleral lenses, these devices have demonstrated great potential to improve vision and quality of life in patients with a wide variety of ocular conditions.'
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Global Specialty Lens Symposium
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Award of Excellence
The GSLS Award of Excellence is given annually to distinguished clinicians, scholars and/or scientists to recognize their lifelong achievements in the field of contact lenses, especially as they relate to specialty contact lenses. This year the GSLS recognized four Scleral Lens Pioneers, each of whom played a significant role in modernizing designs, fitting techniques and patient management at a time when scleral lenses were thought of only as a footnote in history books. Edward Bennett presented the awards, recognizing Don Ezekiel from Australia, Ken Pullum from the United Kingdom, Perry Rosenthal from the USA and Rients Visser from the Netherlands.
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Sur(e)vey
Above mentioned Muriel Schornack also initiated a scleral lens survey with colleagues at the Mayo clinic, an important survey for sure. This survey, SCOPE It Out! (Scleral Lenses in Current Ophthalmic Practice: an Evaluation) tries to find information about scleral lens fits today, so that we can be more sure about things such as: are scleral lenses fitted more for corneal irregularity or for ocular surface disease? The survey seeks individuals who currently fit scleral lenses, and the authors would like to include the experience and insights of as many as possible. The survey will take no more than 5-10 minutes to complete. All participants will be entered in a drawing for a $250 VISA gift card. Please click on the link below, and be sure to participate.
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Traumatic Corneal Scarring
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Corneal Laceration & (R)GPs
 This study evaluated the clinical value of (R)GPs in patients with traumatic corneal scarring and addresses implications of primary corneal repair. Eighteen subjects with a history of corneal laceration were fit with (R)GPs. Scar locations were divided into two zones. The average time between suture removal and (R)GP lens fitting was 5.7±5.5 months. The investigators concluded that (R)GP lens fitting is an ideal method for evaluating visual potential in patients with traumatic corneal astigmatism. Pentacam examinations of those patients with poor visual acuity with (R)GPs can be helpful in understanding existing problems in suture techniques, according to the authors. Photo: Koen Brands
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Size Matters?
 Nejima et al investigated the effect of pterygium size on time-course change of corneal topography after excision surgery of primary pterygium. Based on their study involving 562 eyes, they concluded that topographic changes after primary pterygium excision were indeed associated with pterygium size. Pterygia advancing over the pupillary area required 6 to 12 months for corneal topography restoration, resulting in slow recovery of visual acuity.
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Peripheral Alignment Strategy for (R)PGs
A 41-year-old female underwent a penetrating keratoplasty (PKP) a few years ago and was fitted with a single curve (R)GP corneal lens. She complained about halos, marked discomfort and frequent lens loss. Reverse geometry lenses offer a fascinating approach for fitting (R)GPs after PKP, as this case proves. However, for better comfort and centration, alignment fitting of the peripheral host-cornea is critical. Sometimes more complicated geometries, such as peripheral-toric or quadrant-specific lens designs, are needed to succeed. Once the lens periphery is fitted with alignment, comfort and vision will increase substantially.
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Upcoming Events
- CLSS, March 14-15, Billund (Dk)
- World Cornea Congress, April 15-17, San Diego (US)
- AOMC, April 16-19, Houston (US)
- EAOO, May 14-17, Budapest (HU)
- IACLE 3rd World Conference, May 24-28, Manchester (UK)
- BCLA, May 29-31, Liverpool (UK)
- EurOK, July 10-12, Budapest (HU)
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I-site is an educational newsletter that is distributed on a monthly basis and provides an update on rigid gas permeable related topics (scientific research, case reports and other publications worldwide). I-site is objective and non-political. Its editor Eef van der Worp, optometrist, PhD, FAAO, FBCLA, FIACLE, FSLS is a lecturer for a variety of industry partners, but is not related to any specific company. Please contact us at: i-site@netherlens.com.
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