Which myopia treatment works best?

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There is an increasing amount of evidence demonstrating that the standard of care for children with myopia is to provide proactive myopia control treatments aimed at slowing progression. This approach moves away from single vision correction.¹ This has important benefits for the patient, providing them with more stable vision with less frequent changes in refraction, as well as reducing their lifelong risk of eye disease and vision impairment that can result from increasing levels of myopia.^2,3 The short-term risks of myopia control treatments, such as contact lens wear, are far outweighed by the potential long-term benefits.^3,4

With the growing availability of myopia control treatments and an expanding body of research, knowledge of how to describe their efficacy and how to compare treatments is evolving. Therefore, understanding which treatments are most effective could prove more complex than previously imagined.

The base metric for this evaluation is percentage efficacy, or how much a treatment has slowed refractive or axial elongation progression compared with a control group in single vision correction. Using the gold standard of randomized controlled trial (RCT) data, our current understanding indicates that many treatments offer similar efficacy to slow myopia progression, with no single treatment showing clear superiority. However, some treatments are clearly less effective.^5,6

When looking at outcomes, axial length data provide the most accurate measure and useful gauge for comparison. Axial length data typically yield slightly lower percentages than refractive outcomes within a single study as they are more sensitive at detecting changes in myopia progression.⁵ Consider how refraction can only be measured in 0.25 (diopter) D steps (equivalent to about 0.1 mm), while axial length can be measured down to 0.01 mm.

Percentage efficacy

Within a single myopia control treatment study, a percentage efficacy is an important figure but cannot be compared directly to other studies. Differences in study duration and participant characteristics—such as age and ethnicity—can influence these percentage outcomes. Typically, shorter studies show higher percentage efficacy owing to an initial boost in treatment in the first 6 to 12 months. Younger participant groups and varying ethnicities can also influence percentages due to a faster progression of the control group.⁵

An example of the complexity of percentages is as follows. The MiSight 1 day study was a 3-year RCT, undertaken in a group of children aged 8 to 12 years at outset, with an ethnicity profile of around 55% White (European) and 24% Asian. At 3 years, refractive progression was reduced by 59% and axial elongation by 52% compared with the control group.⁸ The low-dose atropine and myopia progression (LAMP) study, which evaluated pediatric participants in Hong Kong, showed 67% refractive and 51% axial length efficacy over one year.⁹ On first view, the atropine 0.05% appears to be better because of the higher refractive percentage, but the axial length percentages are similar. Also, a 3-year study shows a more robust, sustained effect than a 1-year study. We would conclude that these treatments are likely similar based on their axial length percentage, but the volume of supporting data is stronger for MiSight 1 day.

Additional metrics to understand efficacy include the absolute treatment effect, annualized treatment effect, comparison to previous progression, and comparison to emmetropic eye growth. This article will explore what these various metrics mean and present a simple and clinically actionable approach to understanding and communicating myopia control efficacy.

Absolute treatment effect

This has been proposed as a fairer playing field for efficacy, citing the total diopters or millimeters’ reduction in myopia progression rather than a percentage. It has also been described as the cumulative absolute reduction in axial elongation metric.⁵ Analysis indicates that this may be less influenced by the ethnicity of a study group than the percentage.¹⁰ An important factor here is that shorter duration studies will show a lower absolute number. As an example, the MiSight 1 day study showed a mean of -0.73 D less refractive progression and 0.32 mm less axial elongation in the test group compared with the control group over 3 years.⁸ The LAMP atropine study showed -0.27 D and 0.21 mm less progression over 1 year.⁹ Both outcomes for MiSight 1 day appear far better due to the study duration.

Annualized treatment effect

This accounts for varying study durations by annualizing the absolute effect. A drawback here is that since shorter studies tend to show a higher percentage and absolute effect, due to the initial boost observed in efficacy,⁵ the annualized treatment effect of a shorter study may overestimate the long-term effectiveness of the intervention. As an example, the defocus incorporated multiple segments (DIMS) spectacle lens demonstrated 0.34 mm (62%) less axial elongation over 2 years compared with the single vision control.¹¹ This gives an annualized treatment effect of 0.17 mm. Atropine 0.05% demonstrated 0.21 mm (51%) less progression in the 1-year LAMP study.⁹ This makes atropine look superior based on annualized treatment, while DIMS looks superior based on percentage. When comparing first-year data by the annualized method, though, they are similar since the 1-year DIMS efficacy was 0.22 mm.¹¹

Comparison to prior progression

This approach compares the rate of myopia progression during the treatment period with the rate before treatment in the same individuals. This method translates well to observations of individuals in practice, but can overestimate efficacy, as myopia progression typically slows by around 15% per year as age increases, even without intervention.⁵ Another factor to note is that a percentage calculated this way can look much higher than the RCT percentage. As an example, after the initial 3-year MiSight 1 day RCT, all participants in the control group were switched to wearing the MiSight 1 day treatment lenses.

Over the next 3 years, this group showed a significant slowing of myopia progression, from an average of -1.24 D/0.62 mm in the first 3 years to -0.29 D/0.18 mm in the second 3 years. Calculating the axial length percentage before and after MiSight wear yields 71% efficacy—which seems better than the original 52% in the 3-year RCT6—yet mathematical modeling showed efficacy compared with an age-matched virtual control group was consistent at around 50%.¹²

Comparison to emmetropic eye growth

This newly reported method compares treated myopic eye growth to that of emmetropic eyes, given that some level of eye growth is expected during emmetropization.¹³ If treated eyes show growth rates slowed to that of age-matched emmetropic eyes (approximately 0.1 mm/year), the treatment can be considered highly effective. The advantage of this method is that it can provide age-specific metrics for gauging success. However, the removal of a physiological growth component from outcomes alters the goal posts based on the assumption that some eye growth is typical. This is true for emmetropic eyes, but it is unknown if this is the case for myopic eyes in which excessive axial length is directly linked to long-term eye health risks.¹⁴ This also typically results in higher percentages than the standard percentage myopia control effect.

As an example, analysis of the MiSight 1 day RCT data showed mean 3-year absolute eye growth of 0.30 mm, which when compared with an age-matched cohort of emmetropes (0.24 mm/3 years) represents eye growth slowed to 80% of the emmetropic eye growth rate.¹³ Another recent paper computed the same for highly aspherical lenslet (HAL) spectacle lenses, which showed 0.34 mm (50%) less axial elongation in the 2-year RCT, and 0.41 mm (60%) for a subset wearing their spectacles full-time. In this subset, eye growth rates were similar or slower than those of nonmyopic children in around 90% of full-time wearers.¹⁵

Which treatment should you prescribe?

While it’s important to be aware that several efficacy metrics exist, the clinical translation is simple: No treatment shows clear superiority, with many treatments being apparently similar.^5,6 This allows for prescribing based on what’s available to you and what best suits the patient, since compliance and full-time wear are key to achieving the best outcomes. It makes sense to consider effective optical treatments first, as they offer the dual benefit of myopia correction as well as myopia control.

All of the treatments described above appear to have similar efficacy, alongside orthokeratology¹⁶ and diffusion optics technology spectacles.^16,17 A simplified approach to the clinical discussion of efficacy, based on the vast data available in RCTs, is using percentage categories. This is a variation on the standard percentage, where instead of directly comparing the numbers, treatments are grouped into 2 simple categories of those showing efficacy of at least 50% (based on axial length, the more accurate measure)—which can be described as “slowing progression by at least half”—and those showing efficacy around 33%,^9,18-20 described as “slowing progression by about a third.” These metrics are easy to communicate and are evidence-based, using categorical comparison of all RCTs published with at least 1 year of data.

Figure. The podium presentation of myopia control treatments shown in panel 2 of 4 in the Managing Myopia Guidelines Infographics takes into consideration the outcomes of randomized controlled trials of myopia control treatments where there is at least 12 months of data published. Using axial length data, which is more accurate than refraction in making efficacy comparisons, treatments are grouped into percentage categories based on a comparison of available research. The 2 key categories are 50% and 33%. Note that not all myopia control treatment options are available in all countries, and some treatments may be off-label. (Image courtesy of www.myopiaprofile.com.)

This is the clinical translation advocated in the Managing Myopia Guidelines Infographics, a communication tool that is free to download and available in 20 languages from www.myopiaprofile.com (Figure). One of the take-home messages from the 4 panels of patient-facing infographics is that a number of treatments fit the so-called best category of slowing progression by at least half (>50%). While not all treatments are available in all countries, some are available in most.

Conclusion

The exploration of efficacy in myopia control treatments is important to the field but doesn’t need to complicate the clinical translation, since research indicates that many treatments are similarly effective, with no single option standing out as superior. With numerous highly effective treatment options available, the clinician is able to recommend the treatment(s) that will best suit the patient’s vision, eye health, lifestyle, and myopia control goals. This approach ensures that children receive the most appropriate and effective myopia management, supporting their overall visual health and quality of life.

References:

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9. Yam JC, Jiang Y, Tang SM, 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;126(1):113-124. doi:10.1016/j.ophtha.2018.05.029

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14. Tideman JWL, Snabel MCC, Tedja MS, et al. Association of axial length with risk of uncorrectable visual impairment for Europeans with myopia. JAMA Ophthalmol. 2016;134(12):1355-1363. doi:10.1001/jamaophthalmol.2016.4009

15. Wong YL, Li X, Huang Y, et al. Eye growth pattern of myopic children wearing spectacle lenses with aspherical lenslets compared with non-myopic children. Ophthalmic Physiol Opt. 2024;44(1):206-213. doi:10.1111/opo.13232

16. Sun Y, Xu F, Zhang T, et al. Orthokeratology to control myopia progression: a meta-analysis. PLoS One. 2015;10(4):e0124535. doi:10.1371/journal.pone.0124535

17. Rappon J, Chung C, Young G, et al. Control of myopia using diffusion optics spectacle lenses: 12-month results of a randomised controlled, efficacy and safety study (CYPRESS). Br J Ophthalmol. 2023;107(11):1709-1715. doi:10.1136/bjo-2021-321005

18. Walline JJ, Walker MK, Mutti DO, et al. Effect of High Add Power, Medium Add Power, or Single-Vision Contact Lenses on Myopia Progression in Children: The BLINK Randomized Clinical Trial. JAMA. 2020;324(6):571-580.

19. Sankaridurg P, Bakaraju RC, Naduvilath T, et al. Myopia control with novel central and peripheral plus contact lenses and extended depth of focus contact lenses: 2 year results from a randomised clinical trial. Ophthalmic Physiol Opt. 2019;39(4):294-307.

20. Cheng D, Woo GC, Drobe B, Schmid KL. Effect of bifocal and prismatic bifocal spectacles on myopia progression in children: three-year results of a randomized clinical trial. JAMA Ophthalmol. 2014;132(3):258-264.