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International Newsletter and Forum on Rigid Gas Permeable Contact Lenses, Corneal Shape, Health and Vision |
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Sub-Optical
 A new year, a new beginning. We live in exciting, and sometimes confusing, times. Also times when we won't settle for any suboptimal solution - whatever it is. I see it in our kids. 'It doesn't exist' simply doesn't exist. The solution (to whatever problem, no matter how trivial sometimes) should be available somewhere. Starting with the internet, it is just a matter of finding it. To a large degree, the same is true when it comes to vision. We should not settle too easily for suboptimal optical solutions. We have the best vision correction methods widely available to us that we've ever had. Are 45% of presbyopes astigmatic? While that used to be a technical challenge not too long ago, it is much less the case now in 2016. One of the items in this newsletter covers 'multifocal scleral lenses.' Indeed: if you are looking for a solution, it is most likely available. And if you don't know where to search - why not start at GSLS in Las Vegas in a few weeks. It's the 10th anniversary of this specialty lens symposium. For me, apart from the celebration of an awesome and truly global meeting - it is the celebration of overcoming "sub-optical" solutions and finding better ones for our patients. If you can't find it at GSLS, it may well indeed not exist. See you there hopefully, at Caesar's Palace, for a great start of 2016. Happy New Year! |
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Multifocal Scleral Lenses
Scleral lenses are able to provide excellent vision and comfort as well as treat ocular surface disorders. The use of scleral lenses has become widespread across many ocular conditions, and the indications for scleral lenses continue to grow. Scleral lenses are also becoming more common for treatment of refractive error such as high myopia, high hyperopia, and presbyopia, Melissa Barnett writes in the December issue of Contact Lens Spectrum. The advantage of scleral lenses for patients who have high astigmatism is that lenses can rotate while retaining excellent vision. Patients who have residual refractive error post-laser-assisted in situ keratomileusis (LASIK) surgery are particularly pleased with scleral lenses, as dry eye may be more prevalent in this population. According to the "GP Annual Report 2015," also published in Contact Lens Spectrum, of 130 total respondents, the majority reported fitting multifocal (R)GP lenses. Aspheric lenses were the most common design, with 83% of respondents fitting these lenses. Thirty-one percent of respondents fit scleral multifocal lenses. Thirty-three respondents fit scleral multifocal lenses less than or equal to 30% of the time, and eight fit scleral multifocal lenses more than 30% of the time. Dr. Barnett's article features a full list, with specifications, of all multifocal scleral lenses available on the (US) market.
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Making Progression
Management of myopia continues to be in the spotlight and will be more so than ever in 2016. A review article by Cho et al in Eye & Contact Lens looks at complications of pathologic myopia - the cornerstone of why myopia management is so important. Axial elongation of the eye followed by chorioretinal thinning is suggested to be the key mechanism. Pathologic myopia may lead to many complications, such as chorioretinal atrophy, foveoschisis, choroidal neovascularization, rhegmatogenous retinal detachment, cataract, and glaucoma, the paper states. Some complications affect visual acuity significantly, resulting in poor visual prognosis. This article aims to review the types, pathophysiology, treatment, and visual outcome of the complications of pathologic myopia.
The website and blog myopiaprofile.com iis designed to provide all of the resources required to adopt myopia management into clinical practice. It is built around the clinical Myopia Profile tool developed by Kate Gifford based on over 10 years of actively managing myopia in her Brisbane (AU) practice. The site features a meta-analysis on orthokeratology for myopia control by Paul Gifford.
Paune et al evaluate different options for myopia control with contact lenses, comparing the degree of axial elongation with soft radial refractive gradient contact lenses and orthokeratology with single-vision spectacle lenses (control group) during a period of 1 year before treatment and 2 years after treatment. The soft lens study group was similarly effective to orthokeratology in preventing myopia progression in myopic children and adolescents.
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Optical Outcome of Toric IOLs for Keratoconus
To evaluate the results of toric intraocular lenses in the cataract surgery of patients with keratoconus, Hashemi et al studied 23 eyes of 17 patients with keratoconus who underwent cataract surgery. The amount and axis of the corneal astigmatism were measured by manual keratometry, corneal topography, Pentacam refractive map, and Pentacam equivalent K reading in all patients. The mean best-corrected visual acuity was 0.16±0.09 logMAR, 0.18±0.12 logMAR, and 0.35±0.13 logMAR after the surgery in the mild, moderate, and severe keratoconus groups, respectively. The use of toric IOLs resulted in desirable vision and refraction in the cataract surgery of patients with nonprogressive keratoconus. As for determining the IOL power, it seems that keratometry derived from the 3 mm central zone in the axial map of corneal topography using the SRK/T formula has the lowest error.
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International Academy of Eye Care Professionals
The International Keratoconus Academy (IKA) of Eye Care Professionals is an organization that was established to promote ongoing professional education and scientific development in the area of keratoconus and other forms of corneal ectasia. The mission of IKA is to promote and develop the knowledge base and awareness of the state-of-the-art pertaining to the diagnosis and management of keratoconus and other forms of corneal ectasia. Further, the IKA is dedicated to promoting the awareness and understanding of the most appropriate and effective treatment strategies for managing these diseases. IKA will accomplish its mission by providing an array of educational initiatives that will include live events, web-based education, social media activities and publications in the professional literature. It will also be dedicated to supporting ongoing clinical research. IKA will function as a complementary entity to other organizations that support patients with these diseases, such as the National Keratoconus Foundation (NKCF). These organizations will work cooperatively to establish a comprehensive effort to advance knowledge, awareness and quality of care.
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OK - the importance of topographic difference maps
Orthokeratology plays an increasingly important role in the specialty contact lens practice. Corneal topography is essential while fitting orthokeratology. However, the function of the different maps is often unknown and underused. In this case report, we will highlight the importance of using difference mapping tools to ensure patients' optimal vision and to avoid pitfalls during the orthokeratology fitting procedure. Difference mapping should be performed as a standard evaluation during an orthokeratology fitting procedure to ensure patients' visual outcome and to avoid fitting pitfalls. Due to its subtractive calculation of baseline and current measurements, this represents a more adequate evaluation of the orthokeratology fitting compared to sagittal or tangential mapping alone. Additionally, because the software also provides the topography change in dioptric values, the residual ametropia can be estimated exactly and represents additional objective information for the subjective refraction.
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Upcoming Events
- Global Specialty Lens Symposium, 21-24 Jan, Las Vegas (US)
- NCC 2016, 13-14 March, Veldhoven (NL)
- Specialist Contact Lens and Sclerals Meeting, 17-19 March, Hertford (UK)
- EFCLIN, 28-30 April, Valencia (ES)
- ARVO, 1-5 May, Seattle (US)
- ECLSO, 30 Sept-1 Oct, Paris (FR)
- European Ophthalmology Conference, Sept 21-23, Amsterdam (NL)
- AAO, 9-12 Nov, Anaheim (US)
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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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