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International Newsletter and Forum on Rigid Gas Permeable Contact Lenses, Corneal Shape, Health and Vision |
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It Itches
Recently I heard an interesting hypothesis on eye rubbing in keratoconus. Eye rubbing in relation to keratoconus is not new; Charles McMonnies
has reiterated numerous times the likely connection between the two and the possible link between (the speed of) keratoconus progression and eye rubbing. However, I know of only a few institutes in the world that take this seriously - in the form of advising, informing and coaching their patients in that regard, such as at the NIIOS institute. But the new hypothesis turns it up a notch: could it be, although speculative for now, that part of the success of corneal crosslinking (CXL), in terms of slowing down the progression, may be explained by the fact that after the procedure, patients are afraid to rub their eyes? Could this result in a reduced progression rate? Could it also in theory be true to some degree that wearing scleral lenses (by a lack of rubbing and/or reduced mechanical pressure on the cornea during lens wear) has a similar effect? Many questions and no answers at this point, I am afraid. But it does itch...
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Annual Special on (R)GP Lenses
The October issue of Contact Lens Spectrum has long been a special edition devoted to the topic of (R)GPs. One of the lead articles focuses on 'Scleral Lenses for Severely Diseased Eyes' (Karen Carrasquillo & Gregory DeNaeyer). Eyes that can benefit the most from scleral lens wear are often the most difficult to fit, they state as an opener. Another lead article tries to unravel the issue of 'What Causes Settling in Scleral Contact Lenses?'. Chuck Aldridge describes the complex forces involved in this process: sinking, but also suctioning, squeeze forces and even gravity. He states that as more patients are wearing these contact lenses, it is advisable for practitioners to gain a better understanding of not just how to fit them, but also of one of their idiosyncrasies known as "settling. In 'Current GP Lens Research,' Barry Eiden looks at fluorescein patterns in (R)GP lens assessment (the most appropriate time window to subjectively evaluate [R]GP contact lenses in clinical practice is within 30 to 180 seconds of fluorescein instillation) and initial (R)GP adaptation: symptomatology detected during the first 10 days of adaptation, related to dryness and discomfort, may help clinicians predict participants who will potentially fail to adapt to (R)GP lens wear, he stated. The 'Annual Report 2015' on (R)GP lenses is presented by Ed Bennett.
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Scleral Lens Stability On-Eye
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Do You Have a Vision?
Three lens stabilization methods were integrated into the posterior periphery of a scleral lens to quantify on-eye rotational and translational stability and to model the variation in visual acuity when these movements occur in a wavefront-guided correction for highly aberrated eyes. No statistically significant differences were found in translation and rotation distributions of lens movement of all three designs with peripheral stability modifications. However, the peripheral stability lenses were statistically more stable than the spherical lens with regard to rotation. Simulations of the optical and visual performance suggest that all three stabilization designs can provide desirable results when used in the delivery of a wavefront-guided correction for a highly aberrated eye.
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CXL - Outcome & Outlook
 More on corneal cross-linking, as this technique for the management of keratoconus continues to dominate the ophthalmic literature. One of the issues discussed in a full-access paper 'Controversies in Corneal Collagen Cross-linking' in International Ophthalmology Clinics is that of epithelial-off versus transepithelial cross-linking. With the debate over the long-term efficacy of transepithelial cross-linking still raging, a tantalizing case report of toric application of transepithelial cross-linking has recently been published that demonstrates flattening of keratometry measures tailored to the patient's specific preoperative astigmatism. This broadens the application of cross-linking from corneal topography stabilization to perhaps correction of irregular astigmatism in keratoconus, according to the paper. Another issue, addressed in Eye & Contact Lens, is the impact of CXL on psychological distress and vision and health-related quality of life in patients with keratoconus. A bit more experimental maybe, is a paper in the same journal with the one-year clinical outcomes of a two-step surgical management for keratoconus: topography-guided photorefractive keratectomy/cross-linking technique after intrastromal corneal ring implantation.
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A Custom Made Prismatic Scleral Device for Diplopia
A 55 yo Asian male developed intermittent vertical diplopia with the onset of presbyopia at age 42, worsening with age. With rotationally symmetrical lens designs, prism is allocated to the base down position only; but with the EyePrintPRO design, it is possible to have prism in any direction. To make a custom scleral lens device with prismatic correction, first an impression of the ocular surface is obtained utilizing a special mucous-membrane-friendly polymer. The impression is digitized with a scanning laser, producing a 7-micron-accurate 3-D image of the front surface of the eye. With multifocal correction added to these generated custom lenses, the patient is extremely happy with the comfort and with the clear, comfortable binocular vision free of prism/multifocal spectacles to maintain fusion and near focus.
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GSLS 2016
 The 2016 Global Specialty Lens Symposium (GSLS) will be held on January 21-24 at Caesar's Palace, Las Vegas (USA). The GSLS is a must-attend meeting brought to you by Contact Lens Spectrum focusing on the successful management of ocular conditions using today's specialty contact lenses. The 2015 event was attended by almost 600 registrants from 36 countries. It continues to be the largest conference of its kind in the US. Join your peers in 2016 for the 10th anniversary in Las Vegas!
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Get in Charge!
 The Netherlands Contact Lens Congress (NCC) and the British Contact Lens Association (BCLA) have announced that the BCLA will be working with NCC to run a research symposium as part of NCC 2016 in Veldhoven, the Netherlands on 13-14 March 2016. This biennial conference will be themed GET IN CHARGE. The BCLA's academic team, led by BCLA Academic Chair Professor James Wolffsohn of Aston University, will oversee the abstract submissions and will review them in collaboration with members of the NCC team.
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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: i-site@netherlens.com.
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