Latest Research: IMC2019, Part 1 – Accommodating for Myopia Accomplishments

I'm delighted to bring you some of the many highlights from the biannual International Myopia Conference! In its 17th iteration, it was held from September 12-15 in Tokyo, Japan. Over this four-part news update, I'll summarise some of the more clinically-focused updates in what is traditionally a heavily research orientated conference.

The International Myopia Institute Update

There was a special IMI session at the conference - participants are pictured above (spot me on the far right!). Firstly, the IMI commemorative booklet is available for download from https://myopiainstitute.org/imi-white-papers.html This booklet introduces the IMI, and contains the editorial and introduction paper. Dr Monica Jong, Executive Director of the IMI, is such a good egg that not only did she compile this booklet; she hauled about 30 hard copies over from Australia and they went like hot cakes at the conference! More hard copies will be available at selected conferences.

The next phase of the IMI involves seven new taskforce groups, with an aim to publication in late 2020 / early 2021 and includes;

  • The public health impact of myopia - led by Prof Padmaja Sankaridurg
  • Paediatric high myopia - led by Prof Ian Flitcroft. This is an important topic on which I see more developments coming fourth. As a rough rule, this is being -6D or more by 6 years of age, or if a child has more myopic dioptres than years of age, it’s likely that other syndromic conditions (some life threatening like Marfan’s) could be involved. Ian, a paediatric ophthalmologist, says these children need to be properly diagnosed before their myopia is managed.
  • High myopia in adults and associated complications - led by Prof Kyoko Ohno-Matsui
  • Accommodation and binocular vision in myopia - led by Dr Nicola Logan
  • Preferred practice patterns - led by Prof Jost Jonas
  • Environmental risk factors - led by Prof Ian Morgan
  • Yearly Digest 2020 - an annual summary and update on 2019 published White Papers - led by Prof Earl Smith and Dr Monica Jong.

A clinical digest summary of each report is underway. The Chairs of each current subcommittee (ie. the lead author on each paper) is working with Monica and the IMI team to develop short summaries which will then be translated into multiple languages.

You can learn more about What's next for the IMI in this podcast with Dr Monica Jong.

Monica presented data on the huge impact that the White Papers have had in terms of views, downloads and citations. I was more than a little thrilled to see the Clinical Management Guidelines come out on top - I have all of you to thank for that! As Monica explained, the engagement with the IMI special issue is way above the usual journal citation rates in the 6 months since publication.

Three Japanese researchers presented data on AMFs - think of this as a tremble in the ciliary muscle, like your shaky legs after a long walk or run. A proprietary ‘Fk map’, first developed by Dr Masayoshi Kajita and produced from the Nidek AA2 Autorefractor shows the stability of accommodation for increasing accommodative demand (closer working distance) - where a higher bar means an increased accommodation response (with closer distance in a normal, and flatlining in the poor presbyope); green shows a normal amount of ‘tremble’ and red shows super extreme wobbliness or even accom spasm. The maps at the bottom illustrate how a variety of conditions look on the Fk map. Here are some examples of his Fk maps.

Dr Tomoko Goto presented clinical data where OrthoK was shown to reduce the AMFs compared to SV specs or CLs. Recent research I’ve published from my PhD showed that long term OrthoK expanded the ‘zone of clear single binocular vision’, a wider range of accommodation and vergence compared to single vision SCL wear. This could be relevant to its myopia control efficacy. I didn’t have any progression in my PhD study patients to be able to elicit these relationships, and Dr Goto didn’t report this either. There is some early evidence that a reduced accommodation response (higher lag) in multifocal soft contact lens wearers correlates with a lower myopia control response (Cheng et al 2019); so a better accommodative response could be a mechanism of myopia control. However even if it isn’t, a better BV system probably means better visual comfort.

The take home message? OrthoK is great, and there is so much more research on accommodation at this year’s IMC compared to two years ago! As we understand more, perhaps in future we’ll have a measure or composite of measures of accommodation / BV, and poor accommodators get one type of lens while normal accommodators get another, and this could bridge the gap to higher overall efficacy for our contact lens treatments.

Chi Ho To, Carly Lam and team at Hong Kong PolyU have published their two year data showing a 50-60% efficacy of this spectacle lens for myopia control, which is pretty exciting stuff - Hoya are now planning to release this lens in Asia later in 2019 and probably Australia in 2020. Today’s research presented was on adaptation and acceptance of the lens in adolescents, which is just as important as how well it works from a clinical perspective to ensure successful prescribing in practice.

The DIMS lens features a 9.4mm clear, single vision central zone and then is surrounded by numerous +3.50 add lenslets. The researchers evaluated adaptation and acceptance after 30 minutes and 1 week of either SV or DIMS lens wear with high and low contrast acuity measures and a questionnaire. They also repeated this protocol on 10 adults to avoid a false negative outcome. Here’s what they found:

  1. While 7 out of 20 kids complained about ‘mid peripheral blur’ with the DIMS lenses, 10 out of 10 adults did
  2. Central vision (through the SVD segment) was unaffected, but at near (through the lenslet array) kids lost 3 letters of acuity with the DIMS lens, but the adults lost 1.5 lines
  3. There was no adaptation effect after 1 week - the results from the first 30 minutes stayed the same.

Despite this, 90% of the children reported they preferred wearing the DIMS lens, although in the lecture they also said they’d asked the adolescents ‘which would you prefer if it controlled myopia by 60%’ so that outcome might be biased. Regardless, more spectacle lens options for myopia control are certainly welcome!

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About Kate

Dr Kate Gifford is a clinical optometrist, researcher, peer educator and professional leader from Brisbane, Australia, and a co-founder of Myopia Profile.

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