International Newsletter and Forum on Rigid Gas Permeable Contact Lenses, Corneal Shape, Health and Vision
 March 2016
In This Issue
Column
Myopia Control
Orthokeratology
Scleral Lenses
Light for Sight
I(n)-site-the-practice
Agenda
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Column
The Year of Myopia Control?

Whether going by the Chinese new year or the traditional new year, could this become the year that myopia control kicked in from a clinical perspective? This year's 'Vision by Design' meeting in Scottsdale AZ (USA) will of course focus on that. The meeting originally started as a pure orthokeratology meeting, but it now covers all aspects of myopia control. This year's meeting in April will have speakers covering new information on multifocal soft lenses, spectacles, binocular vision, lighting, and pharmaceutical management. Also on the program are aspects of practice management and how to attain new patients to our practices. Many of us know how to fit the lenses, but are not very good at getting our patients to sign up for these modalities. Huang et al in Ophthalmology compared 16 Interventions for myopia control in children. They found a range of interventions that can significantly reduce myopia progression when compared with single vision spectacle lenses or placebo. In terms of axial length, options including atropine, orthokeratology, peripheral-defocus-modifying contact lenses, pirenzepine and progressive addition spectacle lenses were found to be effective. Paul Gifford and Kate Gifford published a review article recently in Optometry & Vision Science titled The Future of Myopia Control Contact Lenses. Overall, orthokeratology and soft multifocal lenses have shown the most consistent performance for myopia control with the least side effects, the paper states. It also says that the optical characteristics of the individual play a role, though, through variations in relative peripheral refraction, binocular vision function and higher-order aberrations that have been linked to different refractive states.
Eef van der Worp 
Myopia Control
More on Myopia

The Rotterdam consortium on myopia control (NL) is promoting the use of high dose atropine in patients that are at risk for developing high myopia, while suggesting low dose atropine for lower amounts of myopia. One of their concerns is myopic retinopathy in high myopia (defined as over 6D of myopia). In one of their studies, they found a third of severely myopic employees to go blind before retirement age, thus justifying the use of atropine to prevent this, in their view. This topic, addressed by speakers that include the researchers from the team in Rotterdam, will be part of the Dutch contact lens symposium NCC 2016. Among the many variables and risk factors reported in the literature for myopia, the reported higher risk of firstborns developing (higher) myopia is a relatively new one. Although questions remain - including the time spent outdoors between firstborns and younger siblings - the authors of the publication in JAMA Ophthalmology, as quoted in Ophthalmology magazine, state that this may be one of the factors to take into account.
Orthokeratology
Orthokeratology Everywhere
Orthokeratology is gaining a lot of attention in the international peer-reviewed literature. Here is a highlight of a number of papers published or released in 2016 to date. António Queirós and the group at Minho University in Braga (PT) looked at astigmatic peripheral defocus with different contact lenses. They found that orthokeratology, as well as multifocal soft lenses and custom-designed RGP lenses, were able to generate a significant relative peripheral myopia in myopic eyes. A study by Cheng et al published in Contact Lens & Anterior Eye examined the effectiveness of overnight orthokeratology lenses made with a highly gas-permeable lens material for the temporary correction of myopia. They found the lenses and material to be effective and safe for the temporary reduction of myopia. Another study, also published in Contact Lens & Anterior Eye, by Fu et al found that higher spherical equivalent refractive errors is associated with slower axial elongation in patients wearing orthokeratology. On a slightly different note, Fang et al in Eye & Contact Lens studied the bacterial bioburden of orthokeratology lens storage cases. Making orthokeratology lens wearers aware of the bacterial bioburden in their lens cases resulted in improved quality of case care and reduced bioburden. Their results suggest that a strategy of bioburden assessment with forewarning could be a useful method to decrease the incidence of orthokeratology-related microbial keratitis. 
Scleral Lenses
Scleral Lens Sinking into the Conjunctiva and Epislera

David Alonso-Caneiro and the team at Queensland University of Technology in Brisbane (AU) looked at morphological changes in the conjunctiva, episclera and sclera following short-term miniscleral lens wear (16.5mm diameter) in neophytes. Following 3 hours of lens wear, statistically significant tissue thinning was observed across all quadrants, with a mean decrease in thickness of 24 microns, which diminished, but did not return to baseline, 3 hours after lens removal. The most tissue compression was observed in the superior quadrant and in the annular zone 1.5 mm from the scleral spur, corresponding to the approximate edge of the lens landing zone. Compression of the conjunctiva/episclera accounted for about 70% of the changes.
Keratoconus
Light for Sight

 
Light for Sight is uniting clinical institutions, research groups, patient organizations and the private sector to achieve one mission: to eliminate severe visual impairment among all children and adolescents with keratoconus. The flagship program of Light for Sight is "Light for Sight 21," which aims to reduce severe visual impairment among children and adolescents with Down Syndrome, who have a very high prevalence for the disease. One of the goals is to  treat keratoconus by cross-linking in children to prevent the disease as much as possible.  
I(n)-site-the-practice   
Scleral Impingement: What is Your Impression?  

With so much attention on the clearance over the corneal apex and limbus when fitting ectatic corneas, we must equally evaluate the landing zone of the scleral lens: after all, the sclera is what we are fitting. Sadly, this case represents an ocular health risk of scleral lenses: impingement-induced conjunctival hypertrophy. Fortunately, by refitting the patient with a different landing zone in this case, the conjunctival hypertrophy resolved. Impingement occurs when the very edge digs into the conjunctival tissue; blanching may or may not be observed. Compression causes conjunctival blanching, and it can be observed in any sector of the landing zone or even circumferentially. If it is seen at the edge of the lens, compression and impingement are occurring together. Impingement will leave behind arcuate staining as shown in this case, and over time, it may hypertrophy. If any arcuate staining is observed initially at a fitting assessment, it can easily be rectified by loosening the edge of the lens either 360 degrees around, with a toric periphery, or in quadrants depending on what is observed on the eye. If there is elevated hypertrophy, a diameter change may be required either to fit over the hypertrophy by increasing the diameter or by decreasing the diameter and fitting inside of the elevation. For more on this case, and on impingement versus impression, see the link below. 
International Agenda
Upcoming Events
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.