Though no introduction were needed, Professor Lyndon Jones, long time professor at the University of Waterloo where he is director the Centre for Ocular Research & Education (CORE), reminded the audience of his Welsh roots and how his visit during the Six Nations rugby tournament served to reinforce how much he missed pubs and rugby. Though Jones has established a reputation for his research in all areas of contact lens science, his establishing of CORE in recent years is well worth an mention, and the speaker noted that the CORE website is always a useful resource to help keep up to date in this ever-changing area of practice.
Two areas attracting much interest of late are myopia therapy and the debate between silicone hydrogel and conventional hydrogel materials. So these were the focus of this meeting.
Myopia facts
No matter how many times the figures are repeated, they still shock. As publicised by the Brien Holden Vision Institute, myopia is growing around the world with a recent study estimating that, on average, 28% of the world is currently myopic and by 2050, based on current trends, almost 50% will be myopic, representing a sobering five billion people.1 But, as Jones quickly pointed out, there are further trends beneath the headline figures that we need to take into account too. Worryingly, myopia is manifesting at an earlier age now, so people are becoming myopic younger and so become highly myopic at earlier ages. For example, 18% of Singaporeans have reached -6.00DS by age seven. It is thought that by 2060, 10% of myopes will be of more than -6.00DS.
Before everyone rubbed there hand together at the prospect of this commercial opportunity for eye care professionals, Jones cited research underlining the strong association between progressive myopia and eye disease. Such diseases include cataract, retinal detachment, and maculopathy (figure 1). Jones was particularly keen to underline the link with maculopathy, citing that research has suggested the condition is up to 40 times more likely with progressive myopia.2 And maculopathy is a major cause of visual impairment worldwide.
After a brief reference to the Earl Smith findings some years ago that axial length increase in myopia seemed closely linked to peripheral defocus at the retina, Jones referred to papers such as that of Flitcroft3 who has argued that refractive error be thought of as a three-dimensional phenomenon (not just axial) and that lowering progression levels of myopia might reduce the increased risk of maculopathy from 40 times back to nearer two times. Indeed, Jones pointed out, if the axial length can be maintained at less than 26mm, then the risk of visual impairment is minimal (just 3.8%) as opposed to 90% risk for axial lengths of greater than 30mm.
Intervention
Jones began his review of different ways of tackling myopia by reminding the audience of a fact often forgotten. Increasing time outdoors, and therefore exposed to daylight, has some influence on the onset of myopia but no impact on myopic progression once the error is established. Time outdoors influences onset of myopia and not progression. Many Asian schools now enforce outdoor activity regimes for the younger students for this very reason.
Actual slowing down of myopia progression has been shown with a number of interventions with varying degrees of success. The ATOM and ATOM2 studies have shown that the use of atropine can be effective, and the much safer lower dose of 0.01% achieves similar impact with far fewer adverse effects.4 To the surprise of many, Jones noted that no one yet has established why atropine works this way, while also noting that a rebound effect upon ceasing atropine use is still a problem even with the lower dose. The LAMP study has suggested that the 0.05% dose is somewhat better than the 0.01% dose.5
No one wants to continue atropine throughout life. The fact that none of the audience used atropine in myopia therapy is perhaps not a surprise because, as Jones said, the lower dose formulation is not yet commercially available in the UK. It is possible, however, to have the preparation made up by a friendly pharmacist. This would, however, risk some control over exact concentration and quality and also would necessitate the use of a preservative (usually benzalkonium chloride). Problems due to long term photophobia and cycloplegia have yet to be established, but the impact on axial length elongation is ‘not as good as one would like it to be.’
Next up – spectacle correction. Jones first made sure that all the audience knew that under correction of myopia, far from being useful, actually made myopia progression far worse. The use of multifocal and progressive addition lens correction has been shown by studies, such as COMET, to have only minimal impact.6 There have been some specially designed spectacle lenses, such as those developed by the Hong Kong Polytechnic University (PolyU), which have been found to have slowed down myopia somewhat, but more work is needed here.
MySight
The rest of Jones’s talk focused on contact lens intervention. He began by noting that the CooperVision MySight lens was now available in many countries and has been fitted to over 10,000 children worldwide. Any fears people may have when fitting contact lenses to children should be allayed by the important point that the young eye assumes adult proportions very early on in life. For this reason, contact lens parameters for fit should be no different.
Jones was confident to discuss MySight because the lens has been introduced along with a well-designed multicentre study. This has involved three main phases, the first involving the fitting of contact lenses to 144 children of ages eight to 12 at four different centres (in the UK, Portugal, Canada and Singapore). This first phase used parallel double masked groups so that some children were fitted with a standard soft design and others with the MySight and its peripheral hyperopic defocusing design. At the end of the three years, a significant slowing in myopia progression was found in the MySight group (59% reduction in progression of myopia and a 53% reduction in axial length elongation).
Phase 2 involved moving all children into MySight and this has recently shown the slowing of progression to continue, or start in those moving to MySight. A further one year follow up (phase 3) is eagerly awaited and should be announced at this year’s BCLA.
There appears to be no major adverse impact, though a number of children reported some ghosting, though interestingly this was less a problem for neophytes. Jones concluded that intervention at any age could now be assumed to have some benefit.
He concluded with a mention of orthokeratology, which has been found to offer some 50% benefit (so ‘quite effective’), though may raise some concerns about microbial keratitis with overnight wear. He also noted that there have been reports of a rebound effect with orthokeratology treatment upon cessation.
Summary
To quote Jones, ‘We cannot sit there and do nothing. If parents are myopic, we have good data to say we should intervene.’ He cited the IOVS website (iovs.arvojournals.org) as a useful resource online for the latest data, where information is freely available and a ‘must read’.
He reinforced that the impact of MySight will be greatest if used on children showing a faster progression (more than 0.50DS per year) and that, if an individual practitioner was not yet confident to attempt intervention themselves, they still have a duty to discuss it with parents.
The session finished with some useful questions from the floor. Some delegates were interested into why the MySight design had not been made available in a silicone hydrogel lens. It seems that this was simply that such a platform had not been available at the start of the lens production and trials. There were also some concerns about how a si-hi might impact on shorter wavelength exposure to the growing eye. That said, a silicone version is likely in the future. And for ametropia higher than -6.00DS or with a significant cylinder? Jones recommends a supplementary spectacle correction over the contact lenses.
When best to cease MySight treatment is yet to be established, though Jones did point out that when compared with atropine or orthokeratology, adverse impacts were far fewer so longer-term intervention is less of a concern. So, the decision to cease use is ‘likely to be individual.’
The full lecture will be made available on the CooperVision Academy website in the coming months
Useful resources
@coreeyenews
References
1 Holden BA, Fricke TR, Wilson DA, Jong M, Naidoo KS, Sankaridurg P, Wong TY, Naduvilath TJ, Resnikoff S, Global Prevalence of Myopia and High Myopia and Temporal Trends from 2000 through 2050, Ophthalmology, May 2016 Volume 123, Issue 5, Pages 1036–1042
2 Younan C et al. Myopia and incident cataract and cataract surgery: the blue mountains eye study. Invest Ophthalmol Vis Sci. 2002 Dec;43(12):3625-32.
3 Flitcroft D. The complex interactions of retinal, optical and environmental factors in myopia aetiology. Prog Retin Eye Res. 2012 Nov;31(6):622-60.
4. Chia A et al. Atropine for the treatment of childhood myopia: safety and efficacy of 0.5%, 0.1%, and 0.01% doses (Atropine for the Treatment of Myopia 2). Ophthalmology. 2012 Feb;119(2):347-54.
5. Yam JC et al. Low-Concentration Atropine for Myopia Progression (LAMP) Study: A Randomized, Double-Blinded, Placebo-Controlled Trial of 0.05%, 0.025%, and 0.01% Atropine Eye Drops in Myopia Control. Ophthalmology. 2019 Jan;126(1):113-124.
6. Gwiazda JE et al. Five–Year Results From the Correction of Myopia Evaluation Trial (COMET). IOVS, 2006, Volume 47, Issue 13, 1166