Myopia Management The Complex Cases

However, some cases are more complex than others. In this article Soojin Nam discusses the options for customising available interventions. As she points out, doing so requires an understanding of the patient’s binocular vision, safety, and potential for compliance. It also necessitates monitoring for side effects and of course, lifestyle needs.

Eye care professionals today are fortunate to be able to integrate various treatments for myopia control into routine ophthalmic practice, including progressive bifocals, peripheral defocussing lenses, orthokeratology (OK), multifocal contact lenses, outdoor activities, and pharmacological agents.

Intervention options, such as atropine eye drops, highly aspherical lenslet target (HALT) technology (Essilor Stellest), defocus incorporated multiple segments (DIMS) technology (HOYA MiyoSmart), and repeated low level red-light (RLRL) therapy show promise, with some reducing myopia progression by over 50%. Recently, researchers have proposed that 0.05% atropine balances efficacy and safety better than lower concentrations.¹ Combining therapies like atropine with OK or DIMS can enhance outcomes, especially for some of the more complex cases discussed here.

PROGRESSING YOUNG MYOPES WITH A BINOCULAR DYSFUNCTION

The International Myopia Institute’s (IMI) 2021 Reports and Digest included a dedicated paper on myopia and binocular vision.² While the effectiveness of treatments is crucial, the paper highlights the need to consider visual comfort, especially since myopic patients frequently exhibit higher accommodative lag, esophoria, increased accommodative convergence to accommodation (AC/A) ratios, and intermittent exotropia (IXT). Various interventions affect the accommodation and binocular vision systems differently. Any customisation of myopia management requires an understanding of which treatments are supportive and which might adversely affect the visual system.

Atropine

Atropine is a muscarinic receptor antagonist shown to be effective at low doses of 0.01%, 0.025%, and 0.05%.³ As many myopic children will have an accommodative dysfunction, this measurement is a consideration when prescribing atropine, as it is likely to exacerbate existing symptoms. A recent 2024 systemic review listed dose-dependent side effects of low-dose atropine, which included increased light sensitivity, reduction in accommodation function, and tendency towards esophoria demand.⁴ Progressive addition lenses (PALs), bifocal and/or photochromic lenses, as well as prescription sunglasses in conjunction with atropine, can be prescribed to manage side effects. Screen for children with very high AC/A ratios and prescribe higher doses of low-dose atropine with caution. Children can develop convergence excess esotropia (CEET) following 0.01% atropine eye drops, as seen in case studies collected in a report by Kothari et al.⁵ In the unlikely event of sudden-onset esotropia, ensure that the patient is referred for a neuro-ophthalmic assessment and necessary imaging.

Orthokeratology

OK is a reverse geometry rigid contact lens worn overnight. It has been found to increase exophoria6 and reduce accommodative lag, making this treatment a suitable option for patients with low amplitudes of accommodation and esophoria. Children with lower baseline amplitudes of accommodation showed a 56% better myopia control response with OK than myopes with normal accommodation, according to Zhu et al.7 and there is a higher prevalence of myopia among children with IXT. By the age of 10, half of these children are myopic, and by age 20, the prevalence increases to 90%.8 Hence, prescribe with care for patients with intermittent exotropia and high exophoria. The exophoric effect induced by OK could worsen their condition, leading to discomfort and potentially undermining the effectiveness of myopia control.

Multifocal or Dual Focus Contact Lenses

Designed to address a range of visual issues, these contact lenses help reduce accommodative lag by providing additional positive power for near tasks. They help esophoria and high AC/A ratios by inducing more exophoria9 and reducing the need for excessive accommodation. Unlike orthokeratology, multifocal soft contact lenses (MFSCLs) provide a range of near add powers (+2.00, +2.50, and +3.00) that can be increased until the associated near esophoria is neutralised.¹⁰ For patients with accommodative excess, these lenses might be less effective.

Extended Depth of Focus Lenses

Extended depth of focus (EDOF) lenses offer a different approach. These lenses do not significantly alter binocular or accommodative function compared to singlevision lenses. They are designed to provide a clear focus over a range of distances. EDOF lenses offer less central hyperopic defocus, which may limit their efficacy in controlling myopia progression compared to other multifocal designs.

Multifocal and Bifocal Spectacle Lenses

Near plus lenses decrease the accommodative response required for near tasks, leading to an exophoric shift that depends on the power of the near add and the AC/A ratio, while also mitigating near hyperopic blur associated with a high lag of accommodation. Bifocal lenses tend to have a more pronounced effect at similar add powers compared to PALs because the full near power is more readily accessible. Executive bifocal lenses equipped with base-in prism can counteract the near exophoria induced by the near plus power, potentially offering advantages for children with a low lag of accommodation.¹¹ When a near addition lens is integrated into a patient’s distance prescription, it reduces the need for accommodation and causes an exophoric shift, which aims to increase the accuracy of accommodation and decrease retinal blur. Studies have shown that myopic children diagnosed with near esophoria who use single-vision spectacles often experience more rapid progression of myopia than those who use PALs, and those in the PALs group with a greater lag of accommodation exhibit a more substantial therapeutic effect.¹²

Patients who are symptomatic with accommodative/vergence dysfunctions may benefit from vision therapy. Vision therapy can be prescribed alongside any of the modalities of myopia management to improve visual function.

MANAGING THE HIGH MYOPE

All the optical interventions described in this article are similarly available to high myopes, however, there is little data on their efficacy in high myopia. Certain types of lenses may have limitations, as higher powers of prescriptions might not be available.

DIMS lenses are available with powers ranging from plano to -10.00, while HALT lenses extend from +2.00 to -12.00. Hence peripheral plus spectacle lenses (DIMS, HALT) are an option for the high myope, particularly for younger children or patients who are unsuitable for contact lens wear. Given the limitations in refractive index materials, select smaller optical apertures to manage lens thickness and ensure an accurate vertex distance to avoid over-minusing. Placing lenses close to the measured vertex distance during subjective refraction in a trial frame helps simulate real-life wearing conditions.

For a high myope, contact lenses provide benefits in terms of better vision due to reduced image magnification, reduced aberrations, and improved cosmesis. These benefits may translate to an improved quality of life. Soft contact lenses are available in higher powers. Some examples include Mylo (mark’ennovy) up to -15.00D, NaturalVue (Visioneering Technologies Inc) contact lenses up to -12.00D, and MiSight (CooperVision) up to -7.00D. For patients with astigmatism, Biofinity Toric multifocal contact lenses (CooperVision) provide an off-label monthly wear solution with a near add of up to +2.50 and a cylindrical power of up to -5.75 in five-degree steps.

The ideal refractive error for orthokeratology are patients with myopia up to -6.00.¹³ Up to -3.50D astigmatism can be corrected with a toric design.¹⁴ OK can correct higher levels of myopia.¹⁵ When it is not possible to fully correct high myopia, a combination approach using OK for partial correction and spectacles for the remaining refractive error during the day can be effective.¹⁶ A randomised clinical trial showed that highly myopic children (exceeding -5.00D), who used OK combined with daytime spectacles, experienced a 63% reduction in axial length growth compared to those wearing only single vision spectacles.¹⁶

When managing higher degrees of myopia, depending on the lens design, more frequent visits and contact lens adjustment may be necessary for optimal correction. During the fitting process, it is essential to manage expectations and prepare for possible issues, such as increased corneal staining or discomfort, and the need to correct the residual prescription with additional soft contact lenses or spectacle lenses. It is reasonable to consider prescribing a second myopia control intervention that targets the peripheral retina in addition to partial OK, however, the additional efficacy of these combined interventions remains to be determined.

Recently published in 2024, repeated lowlevel red light (RLRL) therapy appears to have stronger treatment efficacy among high myopes.¹⁷ As a non-optical and nonpharmaceutical treatment, this potentially lends itself for dual-therapy with an optical correction, low-dose atropine or orthokeratology.¹⁸

MANAGING THE ANISOMETROPIC MYOPE

Children with myopic anisometropia tend to experience faster myopia progression in the more myopic eye.¹⁹ The prevalence of anisometropia in highly myopic children is higher and more severe anisometropia is associated with a higher degree of cylindrical power, but not spherical power.²⁰

Despite the unclear mechanisms driving asymmetric axial elongation, OK is the only myopia control intervention that has evidence for control of myopic anisometropia.²¹ A recent meta-analysis demonstrated that OK effectively reduced the inter-eye axial length difference in unilateral anisomyopia (one eye is myopic, other eye emmetropic), showing a reduction of 0.27 mm over one year and 0.17 mm over two years. However, for bilateral anisomyopia (where both eyes are myopic for different degrees of myopia), the reduction in mean difference was inconsistent; the more myopic eye experienced slower growth by an average of 0.06 mm over one year compared to 0.13 mm over two years.²¹

HIGH MYOPIA IN INFANTS AND YOUNG CHILDREN

High myopia in children under five to six years of age is not common, with a prevalence of 0.02–0.03% for myopia higher than -6.0D in children under seven years in China and Singapore, and 0.6-0.8% for myopia worse than -4.0D in five to six-yearolds in the United States.²²

An infant or young child with high myopia warrants a closer assessment for any associated medical conditions. Take a detailed history of young infants and children to identify potential genetic factors and symptoms of associated syndromes. Ask about birth history, developmental milestones, and any signs of developmental delays or other health issues. Use age-appropriate visual acuity and colour vision charts. Check for retinal diseases or connective tissue disorders. Measure intraocular pressure to rule out congenital glaucoma (it is possible with handheld rebound tonometers), and when possible, use biometry. Advanced imaging techniques and electrophysiology tests provide essential information for diagnosing inherited retinal diseases.

Optometrists are the frontline eye care practitioners in the initial diagnoses and management of high myopia in young children. Ensure timely referrals to ophthalmologists and tertiary care, and engage with a multidisciplinary team. Provide interventions available for childhood myopia but be practical about the limited evidence of effectiveness for high myopia and syndromic forms. Recommendations for managing myopia progression can be challenging due to limited evidence for these rare cases. Prescribe to prevent amblyopia and support normal development. While contact lenses (at some stage) can be considered for children with significant anisometropia or craniofacial issues, a good starting point for younger patients is the recent peripheral plus myopia control spectacle lenses. They are the least invasive option but be mindful of how easy they are to remove, which may affect compliance as the required wearing schedule is 10 hours or more.

MANAGING THE YOUNG ADULT MYOPE

Bullimore et al.,²³ highlighted that while myopia often begins in childhood, it can also develop in adulthood, between the ages of 18 and 40. School-age myopia generally stabilises around age 15 for about half of those affected. By age 18, roughly 77% have stable vision, and by 21, about 90% have reached stability. For adults, estimates of new myopia cases vary widely, from 15% to 81%. Adult-onset myopia tends to be less severe than childhood-onset and is frequently reported among college students and professionals with high near work demands.

The same optical interventions are available for managing myopia in adults. However, predicting success in adults is challenging due to the slower progression rates. Larger and longer studies are needed to see significant results. Refractive surgery does not stop the eye from elongating over time and may lead to myopia returning later in life, raising questions about the long-term benefits and cost-effectiveness of such procedures.

CONCLUSION

The landscape of myopia management is becoming more sophisticated and personalised. With advancements in both optical interventions like peripheral defocus spectacle lenses, contact lenses, orthokeratology, and pharmacological approaches like low-dose atropine, there are now a plethora of options to consider for every patient, even your more complex cases. Tailoring these treatments effectively requires considering a host of factors such as the patient’s age, the degree of myopia and its progression rate, lifestyle needs, and potential side effects.

SooJin Nam MOptom BOptom MBA (exec) is a part-owner of five Eyecare Plus optometry practices in Sydney and has a strong interest in three main areas: binocular vision dysfunctions, myopia control, and orthokeratology. She was previously a director for both Optometry NSW/ ACT and Eyecare Plus and is a current director of the Australian Optometric Panel. She is a regular contributor to the optometry industry as a key opinion leader.

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