Managing high myopia: Insights from a review of myopia control strategies

Paper title: High Myopia: Reviews of Myopia Control Strategies and Myopia Complications

Authors: Shah R (1, 2), Vlasak N (1), Evans BJW (2)

1. HOYA Vision Care, Amsterdam, the Netherlands
2. Optometry and Visual Sciences, City, University of London, London, UK

Date: Published online July 31, 2024

Reference: Shah R, Vlasak N, Evans BJW. High myopia: reviews of myopia control strategies and myopia complications. Ophthalmic Physiol Opt. 2024 Sep;44(6):1248-1260. 

[Link to open access paper]

High myopia increases the risk of serious ocular complications but most research has focused on low to moderate myopia. While interventions like atropine, orthokeratology (Ortho-K), and myopia control spectacle lenses have shown effectiveness, their specific impact on high myopia remains less clear. This review evaluated the efficacy and safety of pharmacological and optical interventions for slowing axial elongation and refractive progression in children with high myopia (≤-6.00 D). A systematic search of MEDLINE and EMBASE identified 35 eligible studies. The key findings were as follows. 

• Atropine: Atropine (0.5% and 1%) significantly slowed myopia progression compared to controls. Higher doses (≥0.5%) were effective but had more side effects, including photophobia and blurred near vision. Low-dose atropine (0.01%) showed fewer side effects but minimal impact on axial length elongation. Tapering high-dose atropine reduced rebound progression after cessation.
• Ortho-K and novel multifocal RGP contact lenses: Ortho-K effectively slowed axial elongation in high and moderate myopia over 1 year. Partial reduction of Ortho-K combined with spectacles for residual refractive error was beneficial. However, Ortho-K for -6.00D or stronger increased corneal staining risks. Multifocal RGP lenses showed no significant advantage over single-vision spectacles for myopia control over 1 year.
• Spectacle lenses for myopia control: Defocus Incorporated Multiple Segment (DIMS) lenses were less effective for high myopia than for moderate or low myopia.
• Complications of high myopia: The risk of myopic macular degeneration, retinal detachment, cataracts, and glaucoma increased with myopia severity.

The findings emphasize the need for targeted myopia control strategies in highly myopic children, as treatment responses may differ from those with mild to moderate myopia.

Atropine was more effective in slowing myopia progression in concentrations of 0.5% or more, although they were associated with increased side effects and a rebound effect upon discontinuation. Lower dose atropine (0.01%) demonstrated fewer side effects but was less effective in controlling axial length, limiting its effectiveness in high myopia. Clinicians should consider atropine concentration carefully, balancing effectiveness with tolerability. Tapering atropine reduces rebound effects, and progressive addition lenses can help manage atropine-related side effects.

Ortho-K was shown to be an effective option across all levels of myopia. However, higher target reductions (≥6.00 D) increase corneal staining risks, requiring careful fitting and follow-up. One study suggested that a maximum target reduction of no more than -4D should be adopted to avoid corneal health concerns.¹ 

DIMS spectacle lenses, while effective in mild to moderate myopia, show reduced efficacy with increasing myopia. Two of the studies included in the review recommended combining optical and pharmacological interventions to enhance efficacy^2,3

Clinicians should consider individualized treatment plans based on myopia severity, patient tolerance, and long-term safety concerns.

This review highlights gaps in knowledge on long-term safety, efficacy, and best practice protocols for high myopia control, emphasizing the need for further research. Most myopia control research has so far focused on mild to moderate myopia, leaving uncertainty about how well current treatments apply to highly myopic children across different ethnicities and age groups.

The long-term effects of high-dose atropine (0.5% and 1%) remain unclear, particularly regarding ocular health risks and optimal tapering strategies to prevent rebound progression. Similarly, DIMS spectacle lenses appear less effective in high myopia, but further studies are needed to determine whether modified lens designs or combination treatments could improve efficacy. Long-term safety data for Ortho-K are still limited, especially in younger children with high myopia, and the risk-benefit balance of higher treatment targets needs further investigation. 

Expanding research to include adults with progressing high myopia is also crucial, as few studies address myopia control beyond childhood.

Title: High myopia: Reviews of myopia control strategies and myopia complications

Authors: Rakhee Shah, Natalie Vlasak, Bruce JW Evans

Background: Myopia and especially high myopia are recognised as major public health concerns. Although the prevalence of high myopia in young children is low, 10-20% of high school children in Asia have high myopia, with many still progressing, and one in three patients with high myopia develop visual impairment with age. Most participants in myopia control studies have low and moderate myopia; relatively little is known about myopia control in high myopia.

Method: Literature searches were undertaken in MEDLINE and EMBASE to identify publications in English, investigating (Aim 1) the efficacy of myopia control strategies (environmental, pharmacological and optical) in high myopia (≤-6.00 D) and (Aim 2) the complications of high myopia using keywords. Outcomes included change in spherical equivalent refractive error (SE) and/or axial length (AL) to evaluate progression in high myopia

Results:  Aim 1: Twelve studies were identified that reported the efficacy of optical and pharmacological (none on environmental) interventions on AL and SE for high myopia control. A statistically significant reduction in progression of SE and AL in high myopes was reported with 1% and 0.5% atropine. Defocus Incorporated Multiple Segment spectacle lenses had lower efficacy in slowing high myopia progression compared to moderate and low myopia. Ortho-K lenses were equally effective in reducing myopia progression in low, moderate and high myopia. Aim 2: Myopic patients have an increased risk of myopic macular degeneration, retinal detachment, cataract and glaucoma, with the risk increasing with the level of myopia.

Conclusions: High myopia has significant effects on quality of life, risk of pathological complications and vision impairment. Young children, excluding those with some syndromic associations, who are fast progressing moderate and high myopes require early intervention and close monitoring. Further research investigating the efficacy of myopia control strategies in highly myopic patients, both independently and through combination treatments, are necessary.

[Link to open access paper]