Feature, Report

Defusing the myopia time bomb: What will the future hold?

Clinical optometrist DR PHILIP CHENG, who operates The Myopia Clinic Melbourne within his practice Eyecare Concepts, explains the current treatment landscape and why he believes clinical use of axial length measurement will be the next big step for disease management.

Myopia management is arguably the hottest topic in optometry today. The worldwide prevalence of the condition is on everyone’s mind and has led to the development of new technology and highly effective treatment options.

In my myopia control clinic in Melbourne, I see all different presentations of myopia daily. Some children come for a routine eye test and are diagnosed for the first time, others are seeking a second opinion after recent diagnosis, and for many who have had progressive myopia for years – wearing increasingly stronger and thicker glasses – their parents are looking for solutions to slow their progression.

Many parents discover myopia control methods not through their eyecare practitioner, but from family and friends, and their own research. Some are referred from other optometrists and doctors.

I see a range of emotions when I tell parents their child has progressive myopia and what treatments are available. Confusion, guilt, sadness, frustration, anger, despair and hope. It’s all too common I hear parents say that they wish they had known about it earlier. They also wonder why hadn’t anyone told them earlier. I tell them that, regrettably, we cannot go back in time, but we will our best to slow their child’s myopia progression from this point onwards.

In the late 1970s, now-retired Victorian optometrist Mr Maurice Brumer vigorously tried to warn the industry and public about the potential negative effects of wearing single-vision minus lenses for myopia correction. At the time, myopia research and evidence to support his theories were scarce and he was ultimately condemned as an industry disrupter. Forty years on, with our greater understanding of myopia development, perhaps Mr Brumer’s controversial views were ahead of his time.

Dr Philip Cheng believes orthoK and multifocal contact lenses generally yield the best results.

We now have good evidence supporting the use of myopia control interventions. We know the treatments work. Orthokeratology (orthoK), multifocal soft contact lenses, low-dose atropine eye drops, and special spectacle lenses all have a place in our armoury to combat child myopia to maintain better eye health.

The sight-threatening conditions associated with myopia – myopic maculopathy, retinal detachment, glaucoma and cataract – are well known. Yet, more than 50% of respondents in a recently published myopia management survey in Australia indicated they still ‘always’ or ‘mostly’ prescribe single-vision distance spectacles for myopia.

In correcting myopia with optical means, it appears that when we provide the peripheral retina with myopic defocus, eye growth can be modulated and axial elongation reduced. That means prescribing optical aids more advanced than traditional single-vision minus lenses optometrists have routinely prescribed for decades.

Among optical interventions, orthoK and multifocal contact lenses, in my opinion, generally yield the best results in slowing progression, as the peripheral defocus effect is maintained independently of gaze and eye movement.

Research shows contact lenses are very safe for even young children. A recent paper by Dr Kate Gifford, PhD, concluded that the comparative lifetime risk from contact lens wear from a young age is less than the risk of visual impairment from high myopia. My experience is that children as young as five or six, with initial help from their parents, can safety and successfully wear orthoK and soft contact lenses for myopia control. Age itself should not be the determining factor, but the maturity of the child and readiness of the family to start the contact lens journey.

CooperVision’s MiSight 1 day received FDA approval for myopia control.

Recently, the CooperVision MiSight 1 day contact lens received regulatory approval in the US, a landmark decision with significant potential impact on how child myopia is managed. Despite the arrival of new daytime soft lens options, night-time orthoK remains the most popular myopia control treatment in my clinic. The level of interest among optometrists in learning to fit orthoK is at an all-time high. But orthoK fitting demands additional equipment, practitioner skill and experience for best results, whereas multifocal soft lenses are relatively easy to fit and more readily available.

For children who are not ready or suitable for contact lenses, new technologies in spectacle lenses like the HOYA MiyoSmart with Defocus Incorporated Multiple Segments (DIMS) optics – to become available in Australia this year – promise to be a gamechanger in managing myopic children using glasses. Traditional multifocal and bifocal lenses can also slow progression for children with binocular vision disorders such as near esophoria and accommodative lag.

Practitioners need a good grasp of the current knowledge and evidence base of the various interventions, and to continually update their knowledge as new research findings become available. For instance, while the ATOM2 study (2012) showed promise in using 0.01% atropine to slow myopia progression, more recent analysis of this study and newer studies such as LAMP (2018) suggest a dose-dependent therapeutic effect and to prescribe 0.025% or 0.05% atropine for more effective control of axial elongation. Myopia management isn’t static, but constantly evolving.

Part of the clinical challenge is the fact that no two myopes are the same, even from the same family. There is not one treatment that will always be effective for every child. Close monitoring and tailoring the treatment plan for the individual is key to optimal control of myopia progression. That might be to increase the dosage of the atropine, modifying the design of an orthoK lens, changing treatment modality, or adding a secondary treatment such as combining orthoK with low-dose atropine.

Measuring axial length

The single most important technology I have implemented in practice is arguably the measurement of axial length, using the Zeiss IOLMaster optical biometer. Measuring axial length has allowed me to change the conversation with parents about myopia as a refractive error (a vision condition) to eye growth and elongation (eye health condition). After all, if myopia control interventions are aimed at reducing or even halting eye elongation, we need the tools to quantify eye growth and to validate the effectiveness of the treatments we prescribe.

This is particularly helpful for kids wearing orthoK lenses where the true refractive status cannot be measured while on treatment, as well as low-dose atropine treatment where the effect on slowing axial elongation appears to be less than the slowing of refractive change.

Measuring axial length routinely also allows us to assess myopia-related eye health risks in both kids and adults (eyes longer than 26mm are associated with greater risk of uncorrectable visual impairment), urgency of intervention, and to monitor pre-myopic kids identified at risk of developing myopia (eyes destined to become myopic show an increased rate of axial elongation years before the onset of myopia).

The Zeiss IOLMaster optical biometer can be used to measure axial length.

While there are aspects of eye growth that we are yet to fully understand, complete biometric data of axial length, keratometry and refraction provide highly valuable information about the status of a child’s myopia to guide and optimise our management strategy.

Doing myopia management well takes time. It may require a change to how your practice operates. In my clinic I allow up to an hour for an initial myopia assessment consultation. There is a myriad of tests to carry out – refraction, binocular vision workup, axial length measurement, corneal topography, ocular health assessment, and often a cycloplegic examination. But the most time is dedicated to speaking with the parents about myopia, explaining what it all means, setting the goals of treatment and appropriate expectations, and answering the many questions they often have.

Myopia management is both personally and professionally rewarding. There is a great feeling to be had to something positive and proactive. Myopia management is a journey for the child and their family, one that spans many years in your care. By always aiming to provide the best possible experience, my orthoK and myopia control patients are very loyal and their families regularly recommend my clinic to others, helping my practice grow.

Eyecare is all about trust. If the parents are happy with the care and expertise you have shown, the siblings and other family members will invariably follow. If you don’t discuss or offer myopia management for a child with myopia, chances are the parents will eventually find out about it elsewhere, and lose trust in your ability to provide the best care for their family. And they won’t be back.

In time, I anticipate myopia management will become a standard of care that all patients and parents can expect when they walk into an optometrist. As it should be. No child should have their eyes worsen unnecessarily without at least a discussion about how we may prevent such deterioration. When there are effective, evidence-based ways to prevent vision deterioration and reduce the risks of eye disease, doing nothing but prescribing a regular pair single-vision glasses to a progressive young myope may one day be considered a failure to provide adequate care. The time to start myopia management is now.

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