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International Newsletter and Forum on Rigid Gas Permeable Contact Lenses, Corneal Shape, Health and Vision |
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Stay Clean
 Plasma treatments on
(R)GP lenses have become more and more mainstream - even most scleral lenses
are typically plasma treated now. But there is a lot of mist around plasma
treatments. Be aware - a plasma treatment is not a coating: it is a cleaning
process that removes surface debris, oil, waxes and solvents that result from
the manufacturing process. Barry Eiden at the recent American Optometric
Association meeting in Orlando used the analogy that plasma treatment results
in a surface similar to a mirror versus sand paper. This doesn't mean it
isn't working: it leads to a lower initial wetting angle and improves initial
wettability and comfort. But for the long run - we should be looking at
other alternatives. More frequent replacement is still a huge opportunity for
the (R)GP lens industry. In some countries the frequent replacement of (R)GP lenses is reasonable, in
others it is low. The benefits of more frequent replacement have been shown
both clinically and in the literature. When are we going to get clean
with this? Eef van der Worp |
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Scleral Lenses in Shape
 The June issue of Contact Lens Spectrum
contained two feature articles regarding scleral lenses: one on scleral lens
fitting and one on scleral lens shape. In the Modern Scleral Lens Fitting article, Greg
DeNaeyer discusses, among other things, troubleshooting tips for scleral lens
fitting, including lens warping, reservoir debris and seal off/compression. He
also looks at some advanced scleral lens fitting options, including reverse
geometry designs, front toric (optical) scleral lenses and back toric (lens
fit) scleral lenses. The article on scleral shape by investigators affiliated
with the Pacific University (USA) on Exploring Beyond the Corneal Borders shows that the
sclera is not rotationally symmetric but toric, or rather quadrant specific, in
nature. This effect was found to be greater further out on the sclera, but with
a large variation among patients. This means that to optimize lens fit, we need
to follow the shape of the sclera better individually by using toric and
quadrant specific lenses in at least some cases. |
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The Kids are Coming!?
 In light of the newest exciting developments
that make it more and more clear that we may be able to slow down the
progression of myopia with contact lenses in kids - it is crucial to ask
ourselves what we think about kids in contact lenses. Much work in that field
has been done by Jeff Walline and his group at the Ohio State University (USA). The latest article
published in Optometry & Vision Science
reports, as has been reported before, that children are able to successfully
and comfortably wear (R)GP and soft lenses. Long-term adaptation occurred more frequently
with soft lenses than with (R)GP lenses. Of course the choice for (R)GPs or
soft lenses also has to be valued relative to safety and health issues by both
practitioners and parents. The authors found that the amount of time (R)GP lens
wearers are able to comfortably wear their contact lenses may help determine
whether they will remain in that modality, which could prove to be very useful
information in clinical practice. |
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Medical Contact Lens Practice
 Although this book title would
immediately attract the attention of many of us in this exact field, it may not
get the acknowledgment that it deserves. The book does not necessarily focus much
on better lens fitting in a technical sense, but it does provide great insight
into the day-to-day dilemmas that the medical contact lens practice offers.
Much attention is drawn to evaluation of the older contact lens patient, for
instance, but also to allergic conditions and the closed eye (e.g. extended
wear). Also, some chapters are solely devoted to differential diagnosis of the
red eye and to pharmacological and therapeutic considerations. In addition,
post-surgical, scleral, therapeutic and prosthetic lenses each get a chapter in
this book. Not the textbook for the average practitioner, but a great overview
of the medical contact lens practice of today by Elisabeth A.W. Millis, an
ophthalmologist and contact lens practitioner from London in the UK. |
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Multi Opportunities
It is evident today - with an increasing presbyopic patient population
- that contact lens correction of presbyopia can have a tremendous impact on
building an eye care practice. In responding to the questions posed on a popular
consumer contact lens website ( www.contactlenses.org),
the most common question presented pertains to consumers who were told by
their practitioner that contact lens multifocals either do not exist or "do not
work." I-site is proud to have Ed Bennett from the College of Optometry at the University of Missouri St. Louis (USA) present his experience in this newsletter on multifocal (R)GP lenses, as he is one of the best and most influential educators in our field on (R)GP lenses and related topics. See link below for a full overview of multifocal clinical pearls, including different lens designs, how to present multifocal lenses and links to more resources. |
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Sagittal Higher
 Fitting scleral lenses does not have much to do
with the base curve radius in terms of flatter and steeper, but rather with
total sagittal height: to increase it or decrease it to bridge over the cornea.
In this case, the sagittal height was pretty extreme (over 7000 micron) on an
eye with recurrent keratoconus and corneal ectasia after corneal transplants.
The patient wears this lens very comfortably all day without breaks. Photo:
Greg DeNaeyer- Columbus OH (USA). For more information on scleral lenses and scleral lens fitting: visit the www.sclerallens.org website. |
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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 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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