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International Newsletter and Forum on Rigid Gas Permeable Contact Lenses, Corneal Shape, Health and Vision |
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The Tipping Point
 Much is said and written about scleral lenses, about their safety, physiology, efficacy etc. But at the end of the day, handling issues with scleral lenses may prove to be one of the biggest issues defining their success. Sometimes a good result is achieved, with potentially great improvement in visual acuity. But if the patient doesn't like it and/or can't handle the lenses - then all is wasted. Regarding how to handle scleral lenses, a learning curve needs to be factored in: on both the patient's and the eye care practitioner's side it seems. As scleral lenses continue to gain ground, people are getting more innovative. This topic was discussed by Lynette Johns in an earlier version of I-site (discussing the fenestrated plunger with light. And how about this: the use of a simple orthodontic elastic band, as introduced by Blanchard Contact Lens, placed on the finger to much more easily balance the lens so it doesn't tip over? The elastic bands are typically used for braces. They are easy to get, sterile and not very expensive: simply brilliant. See the youtube video on how to apply a scleral lens using this method. Little things like this can sometimes be the tipping point between success or failure of scleral lens wear. Eef van der Worp |
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Making Progress?
The question that keeps popping up, and will be for some time it seems, is: are we making any progress with myopia control with contact lenses in kids? Orthokeratology still has the best track record in that regard. A new study by Downie and Loweby published in Eye & Contact Lens seems to emphasize this once again. The study compared age- and refraction-matched spectacle-wearing kids to orthokeratology lens wearers over a period of up to eight years. In the orthokeratology group, a more stable myopic refractive prescription was found than in the spectacle wearing group. Interestingly, 64% (n=18) in the orthokeratology lens group showed almost no myopia progression (see also next item, on corneal topographical variables in this study). Bifocal soft lenses specially designed for myopia control seem promising, too. The question that remains is: is it safe to fit children? Walline, Lorenz and Nichols in Eye & Contact Lens surveyed 86 (49.2%) soft lens wearers who were fit as children and 89 (50.8%) soft lens wearers who were fit as teenagers. Eighteen (20.9%) fit as children and 17 (19.1%) fit as teenagers reported having had a painful, red eye that required a doctor visit. Overall, there were no differences in ocular health between the groups. The authors conclude that eye care practitioners should not use age as a primary determinant in fitting children in contact lenses.
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Is there 'a' symmetry?
Corneal asymmetry as a potential factor in determining success of controlling myopia progression with orthokeratology was a novel finding by Downie and Lowe, in the paper mentioned above. Asymmetry in the baseline topography map (e.g. before orthokeratology fitting) was higher (1.30�0.25D) in the group showing myopia progression ('the progressors') versus the 'non-progressors group' (0.62�0.25D). The investigators looked at the so-called 'I-S' map (the inferior-superior map), which indicates relative inferior or superior corneal steepening, in this case measured within a 4 mm radius from the corneal apex. The authors speculate that regional topographical differences may affect the orthokeratology lens fit and that treatment forces may be compromised, which may potentially influence the optical outcome of the procedure - and hence the difference in myopia development. The authors suggest quadrant-specific peripheral design orthokeratology lenses to overcome this.
Downie, Lowe - Eye & Contact Lens, July 2013
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CLEKs FDACL
In 1996, the Collaborative Longitudinal Evaluation of Keratoconus (CLEK) study group described the concept of the first definitive apical clearance lens (FDACL) as the flattest lens that exhibited a definite apical clearance fluorescein pattern in keratoconus. To evaluate this fitting technique, a group of investigators from Madrid (Spain) and Braga (Portugal) fitted 109 keratoconus eyes with a popular keratoconus (R)GP lens design, randomly utilizing the traditional three-point-touch system or the described FDACL method. Slightly higher but not statistically significantly different optimal lens fit rates were found between the three-point-touch and the FDACL approaches (83% and 71%, respectively).
Romero-Jimenez, Santodomingo-Rubido, Gonzalez-Meijome - Eye & Contact Lens
July 2013
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Making More of Corneal Topography
Simultaneous multifocal systems for presbyopia are like a question mark for practitioners regarding the optical outcome for the patient. Despite a good refraction and choosing the correct near or distance centered design and the optimal zone diameter, sometimes patients describe halos or double vision of unknown origin. This is especially difficult when a previous contact lens with identical parameters was tolerated well. The ability to measure or image the different optic zones with the lens in situ in such cases would be beneficial. This can be accomplished by performing over-topography - as presented in this case report in this month's I(n)-site-the-practice from Switzerland.
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The Contact Lens Specialist Symposium 2013 will take place 28th & 29th Septemb er 2013 in The Renaissance Hotel, Bath Road, London Heathrow. Keynote speakers will be Patrick Caroline, Eef van der Worp and Randy Kojima who will take you on an exciting journey through optics - from understanding the surface of the eye to optimal contact lens fitting. Our Exhibition will guide you through lens choices as well as offer advice on how to build a successful, sustainable business. www.clss.eu
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Upcoming Events
- GPLI 2013 webinar series
- CLSS, September 28-29, London UK
- ESCRS, October 5-9, Amstrerdam NL
- AAO, October 23-26, Seattle US
- ECLSO, October 25-26, Munich DE
- GSLS, January 23-26 2014, Las Vegas US
- NCC 2014, March 16-17 2014, Veldhoven NL
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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: [email protected].
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