International Newsletter and Forum on Rigid Gas Permeable Contact Lenses, Corneal Shape, Health and Vision
 June 2016
In This Issue
Tap Water
Keratoconus
Advanced Scleral Lens Fitting
Scleral Survey
Orthokeratology after Refractive Surgery
I(n)-site-the-practice
Agenda
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Column
Well... It's the Tap Water

A study from the Centers for Disease Control and Prevention (CDC) by Jennifer Cope et al in Ophthalmology looked retrospectively at Acanthamoeba keratitis (AK) among (R)GP lens wearers in the United States. AK is a rare infection, but it results in severe consequences and potentially significant vision loss. Nine (29% of) patients who developed AK used (R)GP lenses for orthokeratology or therapeutic indication, and overnight wear (including orthokeratology) was considered one of the main risk factors for AK. Other significant risk factors included storing lenses in tap water and topping off contact lens solution in the case. The storage of lenses in tap water is especially a serious risk factor. Maybe to the surprise of some, 12% of households in the US are supplied by private well water, the paper reports, rather than municipal supply - but this was not a risk factor as such. The paper does state clearly, though, that based on instructions to (R)GP lens wearers to rinse lenses with tap water, the wearers may assume that storage in tap water is acceptable as well. To avoid mixed public health messaging, it may be preferable to avoid tap water in ALL steps of the cleaning and storage process. The use of commercial saline as a rinse may be a reasonable alternative to tap water, the paper states. Frequent replacement of the lens case is another recommendation. A final take-home message could be the median time from onset of symptoms to initiation of Acanthamoeba treatment: this was 40 days, with a range of 13 to 1154 days before treatment for this was started. AK should be considered as a possible cause if symptoms arise, even in (R)GP lens wearers.
Eef van der Worp 
Keratoconus
150+

Keratoconus (KC) is a popular topic within our field. A Pubmed search with just the word 'keratoconus' reveals over one hundred and fifty publications in the first couple of months of 2016 alone. Most of the literature is related to treatment, such as corneal cross-linking and instrastromal rings as well as different surgical techniques. A team from Utrecht (NL) in the Journal of Refractive Surgery looks at this from a slighly different angle: What Are the Costs of Corneal Cross-linking for the Treatment of Progressive Keratoconus?From an optical standpoint, another article in the Journal of Refractive Surgery, Repeatability of Wavefront Aberration Measurements With a Placido-Based Topographer in Normal and Keratoconic Eyes, may be of interest to eye care practitioners dealing with KC eyes. Also a study by Naderan in Current Eye Research that looks at the Association between Family History and Keratoconus Severity, which suggests that patients who have more family members with KC should be subject to screening to identify early disease, especially given the new treatment techniques such as cross-linking. A study by Lanza et al in Contact Lens & Anterior Eye looks at the use of different instruments to evaluate intraocular pressure in KC eyes versus normal eyes and post-PRK eyes. Photo: Gustav P�ltner (A) 
Advanced Scleral Lens Fitting
The Next Level

The stream of scleral lens publication is seemingly never-ending today. The last edition of I-site newsletter was a special edition on the topic. To follow up on that, a few papers with good clinical content are listed here. An article by Robert Ensley and Heidi Miller in Review of Cornea and Contact Lenses looks at 'Springtime for Sclerals', including topics such as ocular surface disease and allergies. Greg DeNaeyer in Contact Lens Spectrum covers the topic of 'Troubleshooting Reduced Vision' in scleral lens fitting. For foggy vision, he considers poor surface wetting, reservoir debris and corneal edema as the main potential causes (and he discusses what to do about them). Craig Norman, also in Contact Lens Spectrum, digs a little deeper into the optics of scleral lenses, and more specifically multifocal designs, in 'Scleral Multifocal Power Profiles.' The study from the Michigan College of Optometry concludes that not all scleral designs are created the same, reaching the full add power at different points on the lens. This demonstrates the importance of communicating with your laboratory to fully understand how each presbyopic scleral lens is designed and in what situations each may best be used for your patients. A paper by Barnett et al in Eye & Contact Lens looks at the 'Use of Scleral Lenses and Miniscleral Lenses After Penetrating Keratoplasty'.
Survey in Scleral Lens Wear
Scleral Lenses - According to the Eye Care Practitioner

Muriel Schornack and collegues conducted a large survey looking at scleral lens indications and complications, presented in two posters at the recent ARVO meeting in Seattle (US): 989 individuals responded to the survey, and a total of 84,375 scleral lens fits were reported by respondents to the survey. Based on practitioner-reported outcomes, scleral lenses are associated with a low risk of complications. Conjunctival complications such as hypertrophy and chalasis, which are not commonly associated with other contact lens designs, are observed in scleral lens wearers - but the exact incidence of complications has yet to be defined. Reported isolated complications include: episcleritis/scleritis (reported in 95 patients, or 0.11%), limbal stem cell compromise (reported in 13 patients), graft rejection while wearing scleral lenses (two patients), an elevated intraocular pressure (one patient) and a single retinal detachment. Although the survey found that most practitioners prescribe a corneal gas permeable lens first, more than a third report using a scleral lens as their initial correction for corneal irregularity. Scleral lenses play an important role in improving patient comfort, supporting the ocular surface and improving visual acuity, according to the survey.
Orthokeratology
Effect of OK in Myopic Regression after Refractive Surgery

In the April edition of I-site newsletter, a case report was presented by Baertschi, Wyss, Bolli and Fankhauser from Switzerland on refractive improvements after refractive surgery using orthokeratology lenses. An article in the recent edition of Contact Lens & Anterior Eye - Effect of Orthokeratology in patients with Myopic Regression after Refractive Surgery - comes to the same conclusion. Orthokeratology is an alternative treatment option post-refractive surgery, and this option should be more often considered as a valuable treatment for patients suffering from reduced visual outcomes after refractive surgery. The quality of vision can in some cases be restored, while still offering the freedom from spectacles and contact lenses during daytime hours. In the paper, 21 eyes from 12 patients with myopic regression after keratorefractive surgery were fitted with orthokeratology lenses and followed up for 12.11�3.68 months. The paper states that orthokeratology lenses may be an effective solution for patients with myopic regression following keratorefractive surgery, and it states that estimated K-value can be used as reference value in prescribing orthokeratology.
I(n)-site-the-practice   
The Challenge is Ours      

Fitting a contact lens after a corneal transplant or after refractive surgery is one of the most delicate procedures in our profession. This case report covers the fit of a corneal (R)GP lens, but not just a standard lens: a four-curve-toric-oblong rigid corneal contact lens with reverse curves and ventilation holes is fit, with very satisfying results. A 35-year-old Caucasian male with penetrating keratoplasty in 1994 (OD) and 1997 (OS) due to keratoconus presented to our clinic. Corneal (R)GP lenses are still considered one of the best and healthiest options for the eye, even in more complex eyes like this; however, the lens fit can be more challenging. This case shows that 'going the extra mile' to achieve a good lens fit can result in excellent visual acuities, long wearing times (16 hours per day) and a very satisfied patient. Keeping up the skills needed to fit this type of lenses is crucial - and experienced eye care practitioners and schools together have an important role in teaching the new generation.
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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].