Latest research: International Myopia Conference 2017, Part 1

The sixteenth, biennial International Myopia Conference (IMC) brought together over 350 myopia researchers from more than a dozen countries to drizzly, chilly Birmingham in September 2017, where the latest research was presented in 45 lectures and more than 150 scientific posters over four days. The session topics covered prevalence, progression and risk factors of myopia, mechanisms such as light exposure and visual pathways, optical and pharmacological methods of myopia control, genetics, clinical trial considerations, myopic eye shape and accommodation and binocularity.

Here I am above with my PhD supervisor Katrina Schmid, presenting some of my research on OrthoK and accommodation. In comparison to single vision contact lens wear, we found that accommodative lag reduced, nearwork induced transient myopia reduced - an after effect of near work that tends to be higher in myopes - and tonic accommodation increased - a measure of dark focus showing tone in the accommodation system, which is usually lower in myopes. All in all, myopic accommodation systems after OK treatment appeared to be behaving more like emmetropic systems. This is likely due to the big change in positive spherical aberration after OK, and may also bear some relationship to the big change in relative peripheral refraction and the image shell.

Back to the rest of the IMC, though - below is a selection of six key pieces or areas of research taken from posts I made in the Myopia Profile Facebook group at the time of the conference. I've broken this into two parts. A more detailed write up, published in Australian industry journal Mivision, can be accessed from the link, which includes relevant references.

IMC #1 - outdoor time and sun protection

Research has shown a clear relationship between time spent outdoors and myopia prevention. So when we recommend more outdoor time to our at-risk future myopes, what happens when their parents ask about sun protection?

Seang-Mei Saw from Singapore presented fascinating data where a mannequin set at the average height of a 10 year old boy (137cm, if you were wondering) was fitted with a light sensor, to test the effect of different environmental conditions on luminance:

Open field 18,000 lux hits the eye
Under a tree 8,000 lux
Open field with wrap around class 2 sunglasses 4000-6000 lux, class 3 sunglasses 2000-6000 lux
Open field with wrap around sunnies and a hat 1000-2000 lux
Indoors near a window showed no more lux than indoors without windows, at only 50-400 lux.

The verdict? Slip, slop, slap and slide (this is a longstanding Aussie sun protection campaign) to protect against the sun and myopia. Seeking the shade? is also important, and the brightness of outdoor light in a highly sun protected situation is still magnitudes brighter than any indoor situation, even if near a large window.

IMC #2 - outdoor time in early childhood

Part 1: What's going on in Norway? Lene Hagen presented prevalence data showing that only 13% of their 16-19 year olds are myopic. As it turns out, Norwegian kids and teens all spend a lot of time outdoors, with no relationships to their age or refraction. Right from a young age they're kicked outside each day, regardless of the weather, and it's safe to presume this is fortifying on many levels, not just scleral!

Part 2: Ian Morgan from Sydney presented data showing that kids aged 6-7 years in Sydney spend an average of 20 hours a week outdoors, while their counterparts in Singapore only spend 3-4 hours outside. Once the Singaporean and Sydney kids are 12-13 years old, they spend a similar amount of time outside. Ian championed school based interventions to 'stop generating high levels of myopia' - fitting with the below...

Part 3: Scott Read from Brisbane presented more comparison of 12 year old Australian kids to those in Singapore. Singapore is an interesting location for myopia research due to the high incidence of myopia and nearly uniform highest achievement in literacy, science and maths across the world. Using objective measures of outdoor time (light measuring devices worn by the kids), Aussie kids spend 17% of their school hours day outside while Singapore kids only 7.5%. There was no difference in time spent outdoors after school, or on the weekends compared to weekdays; and Aussie kids had 7 episodes of light exposure per day whereas Singaporean kids only 4.

In summary, a fascinating view of the effect of outdoor time and schooling systems across the world, and their influence on myopia development and progression.

IMC #3 - a new spectacle lens for myopia control

Professor Carly Lam from Hong Kong Polytechnic University described the new DIMS (defocus incorporated multiple segments) spectacle lens design which looks like a fly's eye, covered in tiny lenslets of +3.50 power, less than a micron each in diameter. It has a clear central zone for myopia and astigmatism correction, and the surface area of distance zone to the 'treatment' (add) zone is 50% each, similar to alternating soft multifocal lens designs like the Misight or DISC (defocus incorporated soft contact) lens, the latter which was developed and investigated by the same group. High contrast acuity wasn't affected by the lens design while mesopic acuity was - despite this, the drop out rate was similar to that in the DISC contact lens study. And the results? Around a 60% reduction in both axial elongation and refractive change (by cycloplegic autorefraction) over 2 years in Hong Kong Chinese children aged 8-13 years.

Since the IMC conference, the DIMS spectacle lens was awarded the Grand Prize of the International Exhibition of Inventions of Geneva. It was developed in collaboration with Hoya, who are aiming to have it released in some Asian markets in the second half of 2018, with wider market release likely in 2019.

This is a fascinating development for myopic children not willing or suitable for contact lens wear, and could really offer a viable alternative for these children who aren't likely to get a good myopia control result from progressive or bifocal spectacle lenses.

Read on for part two of the latest research from the IMC.

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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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