International Newsletter and Forum on Rigid Gas Permeable Contact Lenses, Corneal Shape, Health and Vision
 November 2012
In This Issue
Column
Scleral Lenses - Spotlight
Keratoconus - Topography
Ocular Response Analyzer
Myopia & Orthokeratology
I(n)-site-the-practice
Agenda
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Column
What's New?

'What's new in corneal disease' was the title of a fantastic seminar by the college of ophthalmologists in London (UK). A broad array of conditions was discussed, but if we just focus on keratoconus alone, it is of interest to see the cascade of surgical options that are available today to manage the condition. Take corneal cross-linking, for instance: within that modality alone are many different options. The standard procedure is epi-off, but transepithelial treatments may prove to be another choice. Shorter treatments with higher intensity versus longer treatments with lower intensity are options. CXL with intra-corneal rings is an option, too: but in what order? First CXL, or first the rings? Same with topography-guided PRK in combination with CXL. At the same time, as Bruce Allen - consultant surgeon at Moorfields Eye Hospital - pointed out, many surgeons may not always be up to speed with the benefits that contact lenses can have and of the options that are available. Maybe this is a good time to invite the corneal specialists in your area for a session to explore options - we may be surprised by how much we can help each other as well as the patient.

Eef van der Worp

Scleral lenses
Spotlight
 

Contact Lens Update is a website generated by the Centre for Contact Lens Research (CCLR) of the University of Waterloo, Canada and the Brien Holden Vision Institute in Sydney, Australia. Previous 'specials' include topics such as allergies, drug delivery, compliance & presbyopia. In the latest edition, the 'spotlight' is on scleral lenses. Apart from an overview of scleral lenses in the editorial, in the feature review session Siva Balasubramanian evaluates a 2005 article by Kenneth Pullum et al. from Moorfields Eye Hospital (London, UK) that emphasizes the role of scleral contact lenses in the management of various ocular conditions. Melissa Barnett in the 'conference highlight' session looks at the 2012 Global Specialty Lens Symposium poster titled Jupiter Scleral Lenses: The UC Davis Eye Center Experience. Fernando Ballesteros from Bogot�-Colombia in the clinical insight demonstrates the use and effectiveness of a silicone hydrogel scleral contact lens as a bandage lens for a compromised bulbar conjunctiva.

Contact Lens Update - edition 10  

Keratoconus
The Top of the Iceberg

The relationship between the thinnest corneal location and the steepest corneal topography and maximum elevation corneal locations in subjects with keratoconus was investigated by Romero-Jim�nez et al and published in Cornea. The thinnest corneal location was 0.76�0.30mm away from the geometrical center of the cornea, while this was 1.22�0.96mm for the top as measured by axial curvature and 0.93�0.71mm with tangential curvature. This distance was 1.14�0.51mm for front elevation and 1.04�0.41mm for back elevation. Contact lens wear does not affect this lack of overlapping, but the thinnest and maximum tangential curvature locations were found to be located further away from the geometric center of the cornea in the contact lens wearing group versus the non-contact lens wearing group.    

Cornea August 2012 

Keratoconus
The Ocular Response Analyzed

James Wolffsohn et al published a very interesting paper in Cornea regarding 'Changes of Corneal Biomechanics With Keratoconus.' The ocular response analyzer was used to measure the air  

pressure-corneal deformation in keratoconic eyes and in sex-matched controls with healthy corneas. Using the corneal biomechanical data thus acquired, it was concluded that this method could potentially assist in the detection of keratoconus and maybe provide a better insight into the disease, as a 15% higher sensitivity with this method was found compared with keratometry alone and a 5% higher sensitivity compared with keratometry combined with pachymetry was achieved.
Photo: Jan Pauwels UZA - Antwerpen Belgium 

Cornea August 2012 

Orthokeratology
Axial Length & Adverse Advents

Jacinto Santodomingo-Rubido et al in Optometry & Vision Science compared orthokeratology with spectacle wear. According to the authors, the relatively low incidence of adverse advents and discontinuations with orthokeratology is conducive for the correction of myopia in children wearing orthokeratology lenses in this 2-year follow-up report, while at the same time good clinical practice is imperative. From the same author, in Investigative Ophthalmology & Vision Science, is a paper called 'Myopia Control with Orthokeratology Contact Lenses in Spain: Refractive and Biometric Changes.' Orthokeratology contact lens wear reduced axial elongation in this study in comparison to distance single-vision spectacles in children aged 6 to 12 years who had myopia measuring 0.75 to 4.00 diopters. Over 24 months, axial length increased significantly over time: 0.47 mm for the orthokeratology group and 0.69mm for the single vision group. 

I(n)-site-the-practice   
Not Lost in Translation
  

There are many options for the presbyope in the (R)GP lens market today. Translating (R)GP designs generally offer fantastically clear images for distance and near purposes. However, if the reading portion moves under the lower eyelid while reading, near visual acuity will be decreased dramatically. This article by Michael Baertschi, Michael Wyss, Simon Bolli and Marc Fankhauser from Switzerland (but in perfect English) will discuss three different fitting options/modifications to solve an inferiorly mislocated reading segment. Click here for the full report on this topic, which may translate into a successful lens fit.  

International Agenda
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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].