Does ethnicity influence responses to myopia control treatment?

Paper title: Efficacy in Myopia Control: Does Race Matter?

Authors: Mark A Bullimore (1), Noel A Brennan (2)

1. College of Optometry, University of Houston, Texas USA.
2. Johnson & Johnson, Jacksonville, Florida USA.

Date: Jan 2023

Reference:   Bullimore MA, Brennan NA. Efficacy in Myopia Control: Does Race Matter? Optom Vis Sci. 2023 Jan 1;100(1):5-8.

[Link to open access article]

The research behind myopia control options currently available to eyecare practitioners has provided valuable information on the development and progression of myopia.

However, some aspects of myopia control remained relatively unexplained, such as the influence of children's ethnicity on treatment efficacy.

Myopia is increasingly prevalent globally, although studies have found East Asian children have a higher prevalence of myopia¹ and a faster rate of progression.²

Despite this difference in prevalence and speed of progression:

• myopic axial elongation itself appears to be independent of ethnicity³
• both East Asian and Western children have displayed an exponential slowing of progression with age⁴ and
• the associated risks of ocular pathologies related to myopia severity, such as primary open-angle glaucoma and retinal detachment, are similar for East Asian and non-East Asians⁵

In this editorial, Bullimore and Brennan sought to clarify if race was a determining factor in the efficacy of myopia control and, specifically, if the results of studies from studies involving east Asian children could be applied to western children.

They considered the results of two multi-country clinical trials for different designs of soft myopia control contact lenses and three studies which evaluated either a progressive addition lens, overnight orthokeratology or 0.01% atropine, all in different populations. They examined and compared the myopia progression in terms of cumulative absolute reduction in elongation. Neither of the multi-country studies found race made a difference in slowing progression.

The efficacy of myopia control was also found to be similar for the other three modalities for both East Asian and non-East Asian groups.

After reviewing the evidence, Bullimore and Brennan concluded that:

• race was unlikely to influence the treatment effect of myopia control for East Asian and Western children and
• the efficacy of a treatment option will generally be independent of the progression rate.

This means that regardless of whether a child is showing quicker progression due to younger age or being of East Asian descent, they should receive the same benefit from their chosen myopia control treatment as older or western children might.

This review acknowledged that:

• This evaluation is not based on a robust clinical study and none of the studies featured had intended to uncover a relationship between race and treatment efficacy. This may mean the statistical evidence for the lack of differences may be inconclusive.
• However, a lack of evidence that race makes a difference is also consistent across the studies discussed.
• Results giving low efficacy for a treatment may mean assessing the impact of any one covariate is difficult.
• Where many studies are single-site and have little ethnic diversity, there is less chance to highlight racial differences.

Although there are differences in myopic prevalence between different ethnicities, the apparent lack of evidence for differences in treatment responses may point more to cultural differences (e.g, societies with intense education) than biological differences.

Title: Efficacy in Myopia Control: Does Race Matter?

Authors: Mark A Bullimore, Noel A Brennan

Purpose: To evaluate the extent to which results on one race can be extrapolated to others; specifically, can results from studies on East Asian children be applied to Western children and vice versa?

Conclusions: We conclude that, on the basis of available evidence, the efficacy of individual myopia control treatments is largely independent of race. More generally, in terms of slowing of axial elongation, treatment efficacy is independent of progression rate. It does not matter whether the child is progressing faster because they are younger rather than older or because they are East Asian rather than of European descent; the benefit of any myopia control modality seems to be the same.

[Link to open access article]