International Newsletter and Forum on Rigid Gas Permeable Contact Lenses, Corneal Shape, Health and Vision
 December 2013
In This Issue
Column
Myopia Control
Orthokeratology
GPS for (R)GPs
Scleral Lens Settling
Book Review
Piggy-Back
I(n)-site-the-practice
Agenda
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Column
Intolerant

Earlier this year, at the the European Society for Cataract and Refractive Surgery (ESCRS) meeting (which was discussed in the November newsletter), almost all of the 'management of keratoconus' lectures started with, 'If the patient is contact lens intolerant, then...' followed by the specific surgical procedure. Granted: it was interesting to learn about these surgical options. But it made me wonder: how many contact lens intolerant patients are there really today? With the whole arsenal of lenses available, it seems like the majority of such patients may be able to wear a lens. Also, the limited 'life expectancy' of a donor cornea in corneal transplants is another point to consider. One speaker from the United Kingdom stated that the contact lens specialists in their hospital were so good, only limited corneal transplants were performed, and patients underwent surgery only in very advanced stages of the disease. Scleral lenses certainly are part of the palette of lenses available. But other lens options should not be forgotten - as scleral lenses surely aren't the answer to everything. In their column in Contact Lens Spectrum, Patrick Caroline and Mark Andr� list 14 unanswered questions about scleral lenses that are worth reading about in: 'The Unknowns of Scleral Lenses.' Another colleague of ours and a scleral lens enthusiast from Belgium, Jan Pauwels, is presenting this month's 'I(n)-site-the-practice' with a case report on a piggyback lens fit as an alternative to a scleral lens. What a luxury, to have all these lens options at our service. Let's use them. Wouldn't it be cool if 'contact lens intolerance' would to a large extent become a contradictio interminis?

Eef van der Worp 

Orthokeratology
In Control of Myopia Control
 

The November issue of Optometry & Vision Science is completely devoted to myopia control - in an attempt to get control of the many variables involved in controlling myopia. The article highlighted here is by Jacinto Santodomingo-Rubido et al. Orthokeratology, the authors state, is a successful treatment option in controlling axial elongation compared to single vision correction in children of older age, who had earlier onset of myopia, were female, who had a lower rate of myopia progression before baseline, had lower myopia at baseline, had longer anterior chamber depth, had greater corneal power, had a more prolate corneal shape, had larger iris and pupil diameters, and who had lower levels of parental myopia.
Orthokeratology
Myopia Control with Orthokeratology - Is it for Real?
 

The December issue of the American Journal of Ophthalmology compares the safety and efficacy of orthokeratology as a nonsurgical treatment for myopia in children with alternate methods. This perspective from ophthalmology's side by Bruce Koffler and James Sears concluded that orthokeratolgy is as effective as other methods in treating myopia, and is more effective in treating axial elongation. Studies showed orthokeratology to be a safe and efficacious nonsurgical treatment, the authors state.
(R)GPs
GPS
 
A GPS for (R)GPs? That would be marvelous. Just within the (R)GP lens modality alone, it sometimes is hard to maneuver and find your way to the best lens option for the patient. A few articles in the 'Annual GP Issue' of Contact Lens Spectrum actually can be a help in finding our way. Langis Michaud from the University of Montreal (Canada) looks at diameter selection versus patients' needs, and at the clinical impact of higher and lower tear clearances. Melissa Barnett and Brooke Messer considered 'The Developing Role of Scleral Lenses in Today's Society,' which includes a table with different large diameter lenses and also discusses lens diameter selection. Another article worth reading is 'Old-School GP Problem Solving' by  Karen Lee, Diana Nguyen and Timothy Edrington. One of the clinical tips mentioned in their article is that 'if a patient is reporting lens discomfort, pull away the eyelids to see whether the symptom dissipates.' If so, the problem may be lens edge-related, they say. The effect of the eyelids on (R)GP lens comfort and fit is often overlooked, they also state. Also of interest is an article by Neil Pence and Florencia Yeh on selecting (R)GP contact lens materials, which discusses the debate between added oxygen supply on one hand and lens stability, wetting, flexure-resistance and good manufacturing characteristics on the other hand.

Annual GP Lens Special - Contact Lens Spectrum, Oct 2013

Scleral Lens Sinking
All Set(tled)?
 

Matthew Kaufmann from the University of Missouri, St. Louis (US) reported the rates of short-term settling of scleral lenses at the recent American Academy of Optometry meeting. They fitted nine subjects with three different scleral lens designs and measured the central clearance at 0 min., 15 min., 30 min., 45 min., 1 hr., 2 hr., 4 hr., 6 hr. and 8 hr. The authors concluded that the amount of settling of all three scleral lens designs tested in this study varied significantly. On average, the lenses settled a total of 127 microns, 111 microns and 91.13 microns, and approximately 70% of the total lens settling occurred within the first two hours of wear time. Interestingly, clearance values of all three lens designs were still decreasing at the eight hour measurement. The amount of settling was not directly related to lens diameter. Important take-home points for clinicians are to fit scleral lenses with increased vault at the fitting visit to allow for potential lens settling and reduction of vault so as to maintain the desired fitting relationship. The contents of this paper were covered by Loretta Szczotka-Flynn in the November 10, 2013 edition of Contact Lenses Today in 'Scleral Lens Papers at AAO 2013'. 

Book Review
Corneal Topography
  

'Even today corneal topography remains one of the most misunderstood diagnostic tools for the clinician, despite its apparent simplicity, due to unrecognized complexities and oversimplification of formulas'. This is the opening line in the introduction of the 2013 book edited by Aylin Kili� and Cynthia Roberts titled 'Corneal Topography.' The book is based on the input of team of experts and is divided into three sections: basics, devices and applications. Placido disc and Scheimpflug systems both get the attention they deserve. The book is not necessarily written with a contact lens practice in mind, although there is one chapter by optometrist Peter Wilcox on topography-based rigid precorneal lenses. Elevation maps are covered and explained in detail, which could be a major clinical tool in (better) understanding the ocular surface shape and may be very helpful in understanding (R)GP lens fitting. This book most probably is unique in its category, and of interest to anybody who tries to upgrade their knowledge about corneal topography. Kugler publications: discount code (20%): CTB20.  

I(n)-site-the-practice   
Piggy-Backup
  

A patient who has only one functional eye (and a prosthesis OD) keeps us busy. After developing corneal erosions with (R)GPs we fitted him in 2008 with a first-generation hybrid lens, which led to circle-shaped erosions. In an attempt to avoid this, we fitted him with a scleral lens in 2010. This worked well for some time until the patient developed recurrent conjunctivitis, which turned us again toward (R)GP lenses and later to a new hybrid lens. The patient was satisfied with the latter modality, but we remained cautious because of the presence of circle-shaped impression rings on the corneal surface, especially because it is the patient's only functional eye. We then fitted him with a piggyback lens system. The Piggyback lens used has an anterior cut-out that is about 10.20mm wide. This provides better (R)GP lens centration, better comfort for the patient and also prevents the (R)GP lens from slipping away from the soft lens. The patients' vision is the same as with the (R)GP lens alone, but the comfort is much better and the recurrent corneal erosions are no longer an issue. Piggyback is still a valid contact lens modality for eye care practitioners to consider. 

International Agenda
Global Specialty Lens Symposium (GSLS) - Las Vegas

GSLS is gearing up for the 2014 edition of its annual 3.5 day meeting that focuses on the latest techniques and technologies for the successful null management of ocular conditions using today's specialty contact lenses. Accredited for continuing education under COPE, NCLE, and JCAHPO, the meeting will offer approximately 30 credit hours - and last year hosted participants from 32 countries. The first day of the symposium hosts special meetings, where topics like Myopia Control, Billing and Coding, the Aging Eye and Scleral Lens Fitting get all the attention they deserve in sessions from 8:30am to 12:30pm. The full GSLS program is available online; the meeting will be held in the Rio Hotel, Las Vegas (USA).
Upcoming Events
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].