On the day President Donald Trump arrived in London to meet the Queen, there was a fellow US citizen in town who, it is fair to say, was more popularly received by his audience than his compatriot. Over 60 practitioners attended a sell-out meeting sponsored by Visioneering Technologies Inc (VTI) featuring optometrist Dr Thomas Aller as keynote speaker. Dr Aller shared the latest figures on the global myopia epidemic and gave an overview of the current evidence for effective intervention, including data from his own research using various techniques collated over almost 30 years in managing myopia progression.
Impact
Dr Aller first reviewed the various research studies into the prevalence of myopia and the associated risk of pathology. He reminded delegates that myopia is a leading cause of permanent blindness, with a four to five times increased risk of retinal detachment, two to five times increased risk of cataract and two to three times increased risk of glaucoma.1 He quoted a pre-publication statistic from some work by Bullimore and Brennan showing that a one dioptre increase in myopia is associated with 67% increase in the presence of myopic maculopathy.2 Restated, the slowing of myopia by the same amount should reduce the likelihood of myopic maculopathy by 40%.
Peripheral Defocus
Quoting Dr Earl Smith’s work, Aller showed how refractive development is guided by optical defocus and that hyperopic peripheral defocus has been shown to be a driver for increasing myopia. He referenced an article by Berntsen in which the author states ‘all corrections impact peripheral defocus.’3 This was brought home to the audience when the speaker described some of the work undertaken in recent years at the Brien Holden Vision Institute (BHVI), Sydney, Australia, along with that of US contact lens specialist Professor Pat Caroline which clearly shows the power profiles of a range of well know daily disposable lenses.
Knowing contact lenses should ideally create peripheral hyperopic defocus to influence myopia, a concern has arisen that many leading brands, in apparently trying to deal with spherical aberration, actually increase in power away from the optical centre. While typically this is between a -1.00DS and -3.00DS increase in power at 3mm from the centre, the worst example was a -12.00DS lens which increases by over -5.00DS. For balance, Aller also shared with delegates details of lens designs, such as Miru 1-day from Menicon, that have fairly neutral power profiles. In conclusion, the BHVI has shown that, on average, standard soft contact lens designs result in -0.75D of myopia progression per year.
Acceptance
Dr Aller joked with the audience about his presentation to the American Academy of Optometry in 2002 by showing an image of heretics being burnt at the stake, at a time where there was much scepticism about myopia therapy. Using a surfing analogy, he suggested that now is the perfect time to ‘ride the wave’ and start managing paediatric myopia progression, sharing all the contact lens options currently available and both spectacle and contact lens options yet to be released. As an aside, he also discussed a worrying trend he is seeing with dry eye presenting in ever younger patients and shared images of significant meibomian gland loss in patients in their thirties.
NaturalVue
For the end of his presentation, Dr Aller shared data from various sources, including his own practice and from peer-reviewed literature, showing the efficacy of bifocal and multifocal contact lens designs, including two of the CE marked lenses now available for myopia progression management (MiSight from CooperVision and NaturalVue Multifocal from VTI). The data included cycloplegic refractions and axial length measurements, and included one remarkable case that he referred to as the ‘very tall boy with the incredibly shrinking eyes’ where, were it not for the axial length measurements, the 1.25DS reduction in myopia over five years could easily have been explained by inaccurate refraction.
Next, leading optometrist Dr Peg Achenbach (VTI Vice President, Global Professional Services and Clinical Science) took delegates through the unique features and benefits of NaturalVue’s patented extended depth of focus (EDOF) technology. This offers dual positioning in that, as well as being CE marked for myopia progression control, the lens is also approved for presbyopia correction. Achenbach explained that the NaturalVue is ‘different but not difficult’ to fit. With no addition to consider, the lens is fitted much like a single vision lens. Her take home message was that, once practitioners had completed the online learning required to be able to order NaturalVue, they then simply follow each step of the fitting guide.
The final part of the evening was a question and answer session that saw three UK practitioners (Joy Hynes, Elaine Lucas and Kieran Minshull) share their early experiences fitting NaturalVue, primarily on presbyopes. Lucas revealed that she wears the lenses and reported that, after adaptation, she has ‘the best vision at all distances that she’s ever had with a contact lens.’ The panel observed that some patients adapt more slowly than others to the EDOF design. They also reiterated the US clinician’s assertion that, as with fitting any multifocal design, following the fitting guide is key – particularly as the need to push minus power in order for EDOF to work effectively is counter-intuitive. Their overall feedback was that the majority patients they have fitted to date are obtaining good vision at distance, near and usually intermediate too.
Nick Atkins is Director of Marketing and Professional Services with Positive-Impact.
References
1 Flitcroft DI. The complex interactions of retinal, optical and environmental factors in myopia aetiology. Prog Retin Eye Res. 2012; 31: 622–660
2 Bullimore MA, Brennan NA. Myopia Control: Why Each Diopter Matters. Optom Vis Sci. 2019 Jun;96(6):463-465
3 Berntsen DA. Refractive Focus - What Type of Peripheral Defocus Are You Prescribing? Contact Lens Spectrum, November 1, 2014