|Quarterly newsletter on Soft Specialty Contact Lens |
Research, Developments, Designs and Materials FALL 2011
|WORLD WIDE VISION
Individual Designed Soft Lenses
A Must Have!
As contact lens professionals, we use the whole range of products that our industry partners offer. Standard contact lens designs fail in many cases because of difficult corneal and anterior eye topography, and individual lens designs can - and should - be used. Thanks to modern materials, lathe cut designs and individual software fitting programs, these lenses play an important role in our daily practice and should not be neglected. This case report from our practice in Zürich, Switzerland - regarding a successful piggyback lens fit using a custom designed soft lens in a post PMD eye undergoing a corneal transplant - illustrates that individual soft lenses are "must haves" in modern contact lens practice.
|IN THE NEWS|
(Myopia) Controlling the Future?
Axial Elongation Reduction in Myopic Children
Times are exciting for our profession, as for the first time in history our focus may shift from reducing visual symptoms of myopia to potentially reducing the condition itself. Myopia control through specialty lenses garnered a lot of attention at the latest BCLA meeting in the United Kingdom (lectures can be viewed in the BCLA 2011 - post conference section for members of the organisation). One of the most developed markets for myopia controlling lenses is Hong Kong. Nearly 73% of practitioners there prescribe some type of myopia reduction lenses (which include spectacle lenses) according to a survey, as presented by Dr Chi Shing Fan from the Hong Kong Polytechnic University. The criteria for prescribing the lenses varied. Some said 'starting as soon as the child became myopic', but most recommended the treatment if more than 1D of myopia had developed. Graeme Young of Vision Care Research in the UK said that at least twelve myopia control lens patents are available as of today. Nicola Anstice and John Phillips reported in the June 2011 Ophthalmology issue, on the reduced rates of axial length elongation in a group of patients wearing dual focus soft lenses. Currently it seems that between 30-50% myopia reduction may be feasible with different options. Possibly, with customized specialty lenses in the future, this percentage may go up.
|IN THE LITERATURE|
Scleral Shape & Soft Lens Fitting
Limbal & Anterior Scleral Shape vs Lens Fitting Characteristics
Practitioners have always said that information about the shape of the anterior sclera would be beneficial in predicting soft lens fitting characteristics. Now for the first time, we can use optical coherence tomography (OCT) to actually image this and potentially help us in better fitting soft lenses and designing better soft lens geometries. Lee et al from the United Kingdom reported on 'The Influence of Corneo-Scleral Topography on Soft Contact Lens Fit' in the August 2011 issue of Investigative Ophthalmology & Vision Science. Analyzing the limbus and the anterior sclera with OCT can contribute significantly to predicting the soft contact lens fit according to the investigators, accounting for up to 24% of the variance in lens movement. The lens fit in a higher modulus material (as in some silicone hydrogel materials, typically) is more predictable than in conventional hydrogel lens materials, the study found. In the June 2011 issue of Investigative Ophthalmology & Vision Science, Shen and collegues from Miami (USA) also a report on the use of OCT in soft lens fitting: the soft lens edge fitting was characterized by the conjunctival buildup on the eye and by tear film gaps between the back surface of the lens and the ocular surface. Different types of contact lens edge designs (such as round edged lenses and angle edged lenses) presented different levels of conjunctival buildup as well as different frequencies of tear film gaps. This may open new ways of designing soft lenses and evaluating their fit, according to the authors.
|IN THE LITERATURE|
Success with Bandage Contact Lenses
Recurrent Corneal Erosions, Lubrication & Symptom Improvement
The aim of this study was to investigate the symptomatic effect of bandage contact lenses together with regular lubrication for treating recurrent corneal erosions. Thirty-four patients were reviewed. Twenty-seven of the patients (79%) felt that there had been some improvement in their symptoms, and 13 of these defined the improvement as being "cured" from the recurrent corneal erosion syndrome.
Contact Lens & Anterior Eye - June 2011 34: 139-143
|IN THE NEWS|
Soft Specialty Lenses in the Spotlight
AAO, Specialty Lens Symposia & Spectrum's 2011 Contact Lens Summary
At different podiums at various contact lens meetings, soft specialty lenses do receive a lot of attention. At the recent American Academy of Optometry Meeting last week, for instance, Mark André and Patrick Caroline covered 'Custom Soft Contact Lens Design Fitting' in a two-hour session, and Matthew Lampa talked about 'Precision Prescribing of Soft Toric Contact Lenses.' Soft specialty topics will also be prominent on the program at the upcoming Global Specialty Lens Symposium as well as at the San Diego Specialty Lens Symposium.
As a supplement to the July issue of Contact Lens Spectrum, the 2011 Contact Lenses & Solutions Summary hosts a full overview of soft lenses available in the US. Amongst many other categories, more than a full page concerns Multifocal Toric Hydrogels. Tinted lenses and aphakic soft lenses are other categories covered.
Customized Silicone Hydrogel Lens After Contact Lens Induced Corneal Oedema
Hypoxia, Silicone Hydrogel Material, Corneal Topography, Lens Fit
Stromal oedema as well as corneal staining and injection of the limbal and conjunctiva vessels are well known as consequences of over-wearing soft contact lenses. That is the starting point of this case report, which evolved from a corneal physiology complication at first to a mechanical/technical lens fit case resulting in a customized, steep front toric soft lens design manufactured in a silicone hydrogel material. It also proves that obtaining a careful patient history, taking all environmental factors into consideration, can be of pivotal importance for successful of lens wear. This case report demonstrates the challenges we can face in contact lens practice, but with a very rewarding outcome in the end for this patient. Stephan Degle, Stefan Facher and Daniela Oehring from Germany present this case report that demonstrates the successful fit of a Customized Silicone Hydrogel Lens Fit After Contact Lens Induced Corneal Oedema.
Material Selection for Custom Soft Contact Lens Prescribing
Matt Lampa & Mark André
In selecting and prescribing traditional "off-the-rack" soft contact lenses, the lens manufacturer determines the design and material. In contrast, with custom soft contact lenses the contact lens design can be practitioner-specific. That means the base curve, power, thickness and both the optical zone diameter and the overall lens diameter can be specified independent of the material choice. We have now, more than ever, the best options available that allow us to target our lens material selection based on characteristics to better suit our patients' needs. Click here for the full report.
This Newletter is Kindly