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HomemifeatureMyopia Control: Interventions at Your Fingertips

Myopia Control: Interventions at Your Fingertips

Optometry’s fascination with myopia control has never been greater, and with good reason. Around the world, we see a concerning rise in its prevalence, especially post-lockdowns, and we are increasingly aware of the associated risks of permanent blindness as the condition worsens.

Fortunately, clinicians now have several evidence-based interventions that can be used singularly, or possibly in combination, to slow myopia progression.

Whether you choose to dabble on the edges of myopia management, by collaborating with colleagues, or throw your practice into myopia management by investing in upskilling and equipment, you’ll find this article a useful guide to get you started.

Myopia management is an area of optometry that can change lives by setting young people up for a long life in which they can fulfil their potential and their dreams.

With the rapidly increasing prevalence of myopia and its dire consequences when left untreated, it behoves all optometrists to, at the very least, be able to identify patients who may benefit from myopia management

At the heart of myopia management is identifying patients who have, or are at risk for, developing the condition. Once identified, it is about assessing their risks for progressing and developing associated complications over time (such as retinal detachment, myopic maculopathy, glaucoma and cataract). For those at risk, the focus should be on implementing and monitoring appropriate treatments.

Patients suitable for myopia management will typically be aged between six and 14 years, as myopia primarily progresses throughout childhood. The goal will be to slow myopia progression so that the risk of sight threatening complications remains low, or is at very least, reduced from where they would likely have ended up without treatment.

DIAGNOSIS AND ASSESSMENT

With the rapidly increasing prevalence of myopia and its dire consequences when left untreated, it behoves all optometrists to, at the very least, be able to identify patients who may benefit from myopia management.

Fortunately, all optometry practices have the resources to perform a cycloplegic refraction as part of routine clinical care. Doing so is important as it enables you to rule out pseudomyopia, while also determining the extent of your patient’s refractive error prior to commencing treatment or referring on.1 Cycloplegic refraction is a regular aspect of myopia management programs in most instances, and is generally repeated annually after initial diagnosis and treatment initiation. Axial length measurement is another important procedure when diagnosing myopia, assessing its progression over time, and gauging the effectiveness of any interventions.

Axial length – the combination of anterior chamber depth, lens thickness and vitreous chamber depth – is now believed to be more closely related to myopic complications than simply refractive error.2 When axial length growth falls outside the normal rate expected for a patient’s age, the result will almost certainly, inevitably be myopia.2 Furthermore, the ultimate axial length of an elongated eye will influence the risk and severity of complications down the track.1

There are now a few techniques to measure axial length, however the most accurate and repeatable way is with laser interferometry, which has frequent application in IOL determination for patients undergoing cataract surgery. There is currently some controversy over whether axial length measurement is required for appropriate myopia management. If you’re currently dabbling in myopia management, the cost of laser interferometry equipment may be prohibitive but should not necessarily prevent your patients from being measured. My suggestion is that patients can be referred to colleagues, local practices or universities with the necessary equipment for axial length measurement, if desired, as the measurement does not necessarily need to be done immediately after diagnosis. If incorporated into a myopia management program, a patient’s axial length should be measured every six months.

You’ll find out more about axial length vs. refraction in an article by optometrist Philip Cheng, published on page 88 of this issue of mivision.

ENTRY LEVEL MYOPIA MANAGEMENT

So, you’ve decided you want to start managing patients with myopia? Here are a few simple interventions to get you started.

Spectacle Interventions 

Spectacle-based interventions to slow progressive myopia are suitable for a wide range of patients, especially those who prefer not to wear contact lenses or use pharmacological agents such as atropine.

MiyoSmart, a defocused incorporated multiple segments (DIMS) spectacle lens, developed at the Hong Kong Polytechnic University and licensed by Hoya, has been available in Australia since October 2020.

MiyoSmart lenses slow myopia progression via the principle of ‘myopic defocus’, whereby the focus of light experienced throughout the entire retina – not only the central portion – has been found to significantly influence eye growth. Optical treatments for myopia, including MiyoSmart, balance presenting the appropriate defocus of light to the retina, to signal slower myopia progression while simultaneously allowing for the correct central vision correction.3

Impressively, with a central 9.4mm diameter clear zone, this lens design successfully accommodates a wide range of eye movements and viewing directions before patients experience blur at the peripheral treatment zone. The peripheral myopic defocus is accomplished with a ring of approximately 400 small defocus segments, each of which provides a relative +3.50 add effect on top of the back vertex power of the central portion of the lens.4 The almost imperceptible lenslet design of the defocus segments also significantly improves the cosmesis of the lens.

Made from impact resistant polycarbonate, MiyoSmart lenses can be prescribed for up to -4.00D of cylinder, with a maximum combined power of -10D in any meridian, in most cases.

The results from two years of clinical trials with myopic children wearing these lenses, aged eight to 13, were positive. They achieved a mean 52% slower myopic refractive error progression and mean 62% less axial length elongation compared to children wearing single vision lenses.4

Optometrists and dispensers interested in dispensing these lenses are required to complete a short online course. You can contact your Hoya Sales Consultant for more information or freecall (AUS) 1800 500 971 or (NZ) 0800 744 692.

Paul Gifford writes more on the next generation of myopia controlling spectacles on page 90.

Multifocal Contact Lenses in Kids 

CooperVision’s MiSight 1 day lens is a peripheral defocus soft contact lens, and the first intervention to receive regulatory approval for slowing myopia progression as an indication. Now available in many markets, including Australia, it features a concentric ring design, providing a consistent peripheral myopic defocus in different positions of gaze.5

Three years of published clinical trial data have demonstrated that children aged eight to 12, with refractive errors from -0.75D to -4.00D and -0.75D of astigmatism or less, wearing this lens as a daily disposable, experienced 59% retardation in myopia progression. Impressively, they progressed just -0.51 ± 0.64D over three years, compared to -1.24 ± 0.61D in the eyes wearing single vision contact lenses.5 Similarly, the MiSight 1 day group achieved 52% less axial length progression compared to the control.5

Fitting these lenses is similar to fitting single vision lenses, and available data from clinical trials have not reported any serious adverse events with their use. In most cases, the reported incidence of adverse events to contact lens wear seen in children in these clinical trials is similar, if not lower, than that seen in adults wearing soft lenses.5,6 

MiSight 1 day clinical trials suggest little or no rebound effects in the year following discontinuation when patients are treated with this intervention for two years.7 However continued monitoring, or slow titration of treatments is recommended, particularly in children who are still growing when treatment is discontinued.

CooperVision’s Proclear Multifocal and Biofinity Multifocal ‘D’ lenses theoretically have an appropriate optical profile for a myopia control effect and have been the subject of clinical trials to establish their role as myopia control treatments off label.8

MORE SERIOUS ABOUT MYOPIA MANAGEMENT

Orthokeratology 

Rigid gas permeable orthokeratology (OK) contact lenses can be an effective intervention to slow the progression of axial elongation, especially among younger patients who are progressing quickly.

Worn overnight, these lenses reshape the cornea and correct refractive error, producing a mid-peripheral thickening of the cornea, and thus a peripheral add effect when used on myopic patients. A 45% overall slowing of axial length progression with this form of correction has been reported,9,10 with similar effects from both spherical OK and toric OK lens wear.11,12 

For most patients, OK lenses undoubtedly offer convenience, as all the reshaping and refractive correction occurs overnight. However, this needs to be weighed up against potential risks and complications of overnight contact lens wear, including microbial keratitis. Patients should be informed that there is a risk of infection with OK, although it is reportedly similar to other forms of overnight contact lens wear.13 

If you are interested in using OK as a myopia intervention, you will need access to a corneal topographer and potentially an OK lens fitting set (some laboratories can send initial lenses using only topography data, thus removing the need to purchase the fitting set).

Contact lens laboratories can provide valuable training, support and trouble shooting. Societies such as the Cornea and Contact Lens Society of Australia and its chapters, and the Orthokeratology Society of Oceania, offer an abundance of resources and support.

FOCUSSED ON MYOPIA MANAGEMENT

Low Dose Atropine 

While we remain unsure of the mechanism of action, clinical trials show that daily use of atropine eye drops can successfully slow myopia progression.

Important to note is that the dosage of atropine is critical to balancing success and preventing unwanted and uncomfortable drug side effects (such as light sensitivity and an inability to focus on objects at near). Commercially available 1% atropine eye drops, for example, have been shown to achieve an impressive 77% reduction in myopia progression, compared to controls, when used daily over two years.14 Unfortunately, this comes with significant side effects of mydriasis and cycloplegia, with children within 1% atropine trials reliant on photochromic progressive addition lenses for functional vision.14

In the seminal Atropine for the Treatment of Myopia 2 (ATOM2) trial, similar efficacy in myopia control was reported between groups using daily 0.5%, 0.1% and 0.01% atropine. This led to a recommended 0.01% dosage which achieved the most acceptable adverse effect profile, although its ability to slow axial length growth was questionable.15 Concentrations trialled, of 0.025% and 0.05%, have subsequently been shown to have a greater impact on myopia progression, including axial length, while still having an acceptable adverse effect profile.16

Prescribing atropine in Australia for myopia control has some requirements. Optometrists require therapeutic endorsement to prescribe the drug and atropine eye drops are only commercially available at a 1% concentration. Lower dose concentrations thus require the services of compounding pharmacies with specialised facilities required for the appropriate complex compounding of ophthalmic medications.17 These pharmacies are often located in major urban centres, however fortunately, they will usually fill prescriptions and send them via post if required.

Due to the various doses of atropine that can be used to treat myopia or other conditions, and the risks of side effects with higher doses, I recommend using the words “To be compounded”, or similar, on the prescription and ensuring the dosage required is extremely clear. Additionally, alert your patient to how the correct preparation will be described on the label, that it needs to be filled through a special compounding pharmacy, and the potential side effects with higher than recommended dosages to watch out for in case of dispensing errors.

Monitor for any issues associated with incorrect dosage by assessing the patient’s pupils and accommodation at follow-up appointments. Single use, unpreserved formulations can also be prescribed if preservatives, such as benzalkonium chloride are to be avoided, although this often comes with additional cost.

Treatment with atropine usually continues for at least two years, however once treatment is stopped, there is often a significant rebound effect of accelerated axial length growth, especially among patients on higher doses.18 It is often recommended to begin stopping treatment gradually as the patient ages to over 13 years, especially if their myopia progression has significantly slowed, as this indicates they are likely to stabilise naturally over time.18 If progression recurs once treatment is discontinued, atropine can successfully be reinstated to again slow progression.18

The use of low dose atropine to manage myopia is discussed in greater detail, by Dr Loren Rose, on page 53 of this issue of mivision.

Combination Treatments 

The potential (both positive and negative) to manage myopia with a combination of interventions, such as myopia control lenses (spectacles, soft contact lenses or OK) with pharmacological treatments such as atropine, is often discussed. Trials combining OK with 0.01% atropine have suggested greater effect when used together rather than using OK alone.19,20 An ongoing trial investigating the combination of soft multifocal lenses (the Biofinity ‘D’ Lens) with 0.01% atropine, has published baseline data and should provide eventual insight on the utility of combining these two treatments.21

WHAT’S STOPPING YOU?

As an optometrist, you are ideally placed to initiate and monitor myopia management interventions – you have the training and access to further training, and much of the equipment is already available in practice.

Whether you are starting out, or seriously venturing into myopia management, I encourage you to guide your clinical practice by keeping up-to-date with the literature on the best, evidence-based treatments for myopia control over time.

This continually evolving area of practice will be extremely rewarding for you, your patients and their families alike.

Alex Hui, OD, PhD, GradCertOcTher, FAAO is a Senior Lecturer at the School of Optometry and Vision Science, UNSW Sydney, Sydney. 

References 

  1. Gifford KL, Richdale K, Kang P et al. IMI – Clinical Management Guidelines Report. Invest Ophthalmol Vis Sci 2019; 60: M184-M203. 
  2. Debbie Jones, BSc, FCOptom, FAAO. Measure Axial Length to Guide Myopia Management. Review of Myopia Management. reviewofmm.com/shouldnt-we-treat-axiallength- as-essential-in-treating-myopia 
  3. Tse DY, Lam CS, Guggenheim JA et al. Simultaneous defocus integration during refractive development. Invest Ophthalmol Vis Sci 2007; 48: 5352-5359. 
  4. Lam CSY, Tang WC, Tse DY et al. Defocus Incorporated Multiple Segments (DIMS) spectacle lenses slow myopia progression: a 2-year randomised clinical trial. Br J Ophthalmol 2020; 104: 363-368. 
  5. Chamberlain P, Peixoto-de-Matos SC, Logan NS et al. A 3-year randomized clinical trial of misight lenses for myopia control. Optom Vis Sci 2019; 96: 556-567. 
  6. Cheng X, Brennan NA, Toubouti Y et al. Safety of soft contact lenses in children: retrospective review of six randomized controlled trials of myopia control. Acta Ophthalmol 2020; 98: e346-e351. 
  7. Ruiz-Pomeda A, Prieto-Garrido FL, Hernández Verdejo JL et al. Rebound Effect in the Misight Assessment Study Spain (Mass). Curr Eye Res 2021: 1-4. 
  8. 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: 571-580. 
  9. Wildsoet CF, Chia A, Cho P et al. IMI – Interventions Myopia Institute: Interventions for Controlling Myopia Onset and Progression Report. Invest Ophthalmol Vis Sci 2019; 60: M106-M131. 
  10. Sun Y, Xu F, Zhang T et al. Orthokeratology to control myopia progression: a meta-analysis. PLoS One 2015; 10: e0124535-e0124535. 
  11. Cho P, Cheung SW. Retardation of myopia in Orthokeratology (ROMIO) study: a 2-year randomized clinical trial. Invest Ophthalmol Vis Sci 2012; 53: 7077-7085. 
  12. Chen C, Cheung SW, Cho P. Myopia control using toric orthokeratology (TO-SEE study). Invest Ophthalmol Vis Sci 2013; 54: 6510-6517. 
  13. Bullimore MA, Sinnott LT, Jones-Jordan LA. The risk of microbial keratitis with overnight corneal reshaping lenses. Optom Vis Sci 2013; 90: 937-944. 
  14. Chua WH, Balakrishnan V, Chan YH et al. Atropine for the treatment of childhood myopia. Ophthalmology 2006; 113: 2285-2291. 
  15. Chia A, Chua WH, Cheung YB et al. Atropine for the treatment of childhood Myopia: Safety and efficacy of 0.5%, 0.1%, and 0.01% doses (Atropine for the Treatment of Myopia 2). Ophthalmology 2012; 119: 347-354. 
  16. Yam JC, Li FF, Zhang X et al. Two-Year Clinical Trial of the Low-Concentration Atropine for Myopia Progression (LAMP) Study: Phase 2 Report. Ophthalmology 2020; 127: 910-919. 
  17. Trivedi A, Katelaris C. Presentation, diagnosis, and the role of subcutaneous and sublingual immunotherapy in the management of ocular allergy. Clinical and Experimental Optometry 2021; 104: 334-349. 
  18. Chia A, Lu QS, Tan D. Five-Year Clinical Trial on Atropine for the Treatment of Myopia 2 Myopia Control with Atropine 0.01% Eyedrops. Ophthalmology 2016; 123: 391-399. 
  19. Kinoshita N, Konno Y, Hamada N et al. Additive effects of orthokeratology and atropine 0.01% ophthalmic solution in slowing axial elongation in children with myopia: first year results. Jpn J Ophthalmol 2018; 62: 544-553. 
  20. Wan L, Wei CC, Chen CS et al. The Synergistic Effects of Orthokeratology and Atropine in Slowing the Progression of Myopia. J Clin Med 2018; 7. 
  21. Huang J, Mutti DO, Jones-Jordan LA et al. Bifocal & Atropine in Myopia Study: Baseline Data and Methods. Optometry and vision science : official publication of the American Academy of Optometry 2019; 96: 335-344.

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