Myopia Profile

Clinical

Assessing risk of myopia onset and progression

Posted on August 2nd 2019 by Kate Gifford

Identifying the pre-myope

There are four key principles for assessing risk of myopia onset:

  • Family history - one myopic parent increases risk by three-fold, while two myopic parents doubles this risk again1
  • Visual environment - less than 90 minutes a day spent outdoors increases risk, especially if combined with more than 3 hours a day spent on near work activities (outside of school time)2
  • Binocular vision - Children with higher accommodative convergence (AC/A) ratios, typically seen with esophoria, have an increased risk of myopia development within one year of over 20 times.3 Accommodative lag may also be a risk factor but there is conjecture.4 Intermittent exotropia has also been associated with onset of myopia.5
  • Current refraction - the most significant risk factor of this lot for future myopia is if a child exhibits 0.50D or less of manifest hyperopia at age 6-7. This risk is independent of family history and visual environment.6

In addition to this, the fastest rate of refractive change in myopic children occurs in the year prior to onset,7 so the child who is less hyperopic than age normal should be closely monitored, especially if concurrent risk factors are evident.

Identifying the myopia progressor

  • Age - the younger a child becomes myopic, the faster they will progress, with children 7 years of age progressing by at least 1D per year with this halving by age 11-12.8
  • Family history - children with two myopic parents have been shown to be the fastest progressors in single vision spectacle and atropine corrections, and children with one myopic parent progress less than the former but more than the child without such family history.9, 10
  • Visual environment - near work at less than 20cm working distance and durations of longer than 45 minutes have been linked with more myopia progression.
  • Ethnicity - Asian ethnicity has been linked to faster myopia progression8, 11
  • Binocular vision - watch for esophoria, accommodative lag and intermittent exotropia. In myopia control studies of progressive addition spectacle lenses (PAL), children with esophoria in single vision spectacle control groups were found to progress more quickly, 12 and children with a larger baseline accommodative lag in the PAL groups showed statistically greater treatment effect.13 Children with lower baseline accommodative amplitude have shown a greater myopia control response to orthokeratology contact lens wear compared to normal accommodators.14 Finally, while the effect of controlling IXT on controlling myopia has not yet been studied, 50% of children with intermittent exotropia (IXT) are myopic by age 10 and 90% by age 20.5 

Essentially, any myopic child is a progressor until proven otherwise! The institution of a myopia control strategy as early as possible is evidence based practice, especially by age 9. The Myopia Profile Managing Myopia Guidelines Infographic, patient brochure and customizable insert (free to download) help to explain risk using a racing car analogy - each of the risk factors above 'fuels' the myopia car towards both onset and progression of myopia.

Myopia-risks-infographic.jpg

Meet the Authors:

About Kate Gifford

Dr Kate Gifford is an internationally renowned clinician-scientist optometrist and peer educator, and a Visiting Research Fellow at Queensland University of Technology, Brisbane, Australia. She holds a PhD in contact lens optics in myopia, four professional fellowships, over 100 peer reviewed and professional publications, and has presented more than 200 conference lectures. Kate is the Chair of the Clinical Management Guidelines Committee of the International Myopia Institute. In 2016 Kate co-founded Myopia Profile with Dr Paul Gifford; the world-leading educational platform on childhood myopia management. After 13 years of clinical practice ownership, Kate now works full time on Myopia Profile.

Back to all articles

Enormous thanks to our visionary sponsors

Myopia Profile’s growth into a world leading platform has been made possible through the support of our visionary sponsors, who share our mission to improve children’s vision care worldwide. Click on their logos to learn about how these companies are innovating and developing resources with us to support you in managing your patients with myopia.