Article

MYOPIA MANAGEMENT: HOW TO GET STARTED

A step-by-step guide to integrating myopia management into practice.

When the World Health Organization (WHO) published its first report about myopia in 2015, which identified this refractive error as a significant risk factor for ocular pathology leading to legal blindness, eye-care practitioners (ECPs) began to listen.1 In 2019, the WHO confirmed the prevalence of high myopia, reaffirming its initial statement and encouraging every ECP to take action.2 It is increasingly apparent that addressing myopia progression is no longer optional.

This article defines a pathway for integrating myopia management into practice for practitioners who want to join the resistance against myopia. Here, the term “management” refers to managing both refractive error and axial length.

STEP 1: UPDATE YOUR KNOWLEDGE

Every ECP is able to perform a refraction and to prescribe and sell corrective lenses to improve distance vision, but not every practitioner is fully aware of the recent findings in the field of myopia. These include genetics, environmental factors, and the latest effective options to manage myopia over time. Science evolves rapidly, and we know more now than ever about myopia. While questions remain unanswered, that is no reason to be unconcerned about the myopia epidemic and, consequently, fail to take action.

Recent white papers by the International Myopia Institute (IMI) comprise a solid reference for anyone interested in expanding his or her knowledge of the theoretical and practical aspects of myopia management.3-6 The IMI papers establish a strong foundation for practitioners to learn the latest information about this topic, citing evidence-based research and publications. They are open-access and represent the first step toward a comprehensive update on myopia (https://iovs.arvojournals.org/issues.aspx?issueid=937872#issueid=937872 ).

Lectures at national and regional meetings, webinars by experts in the field, and unbiased, non-commercial websites—such as myopiaprofile.com and worldcouncilofoptometry.info/brien-holden-vision-institute-myopia-education-program —are also valuable sources for information about new treatment options. Speaking with colleagues who have established myopia management programs is another way to learn how to develop this specialty practice.

Your staff should also be involved in this journey. They should learn as much as possible to correctly inform parents about the importance of preventing eye diseases and the options available to treat their children. They should be able to handle most of the common questions and help lay the groundwork with parents for the next clinical steps. It is important to inform parents of potentially alarming signs or symptoms associated with contact lens wear that would necessitate an emergency visit. This teamwork requires that everyone in the practice speaks the same clinical language.

STEP 2: CONSIDER EVERY CHILD POTENTIALLY MYOPIC

Myopia management does not start when refractive error is confirmed through cycloplegic refraction. It starts whenever a child who may become myopic enters your practice. You can predict which patients will become myopic by looking at the progression of their refractive error and, most importantly, at their axial length in the years preceding myopia onset. The presence of 0.75D or less of hyperopia at the age of 6 years indicates that myopia is likely to develop in the near future.7 A significant reduction in the amount of hyperopia is also highly predictive of myopia onset. Even more predictive is rapid axial elongation in the year before children become myopic.8

Some characteristics may help us identify children who could become myopic in the future. Genetics can explain only part of the degree of myopia.4 Having two myopic parents, as well as myopic grandparents, significantly increases a child’s risk of developing myopia; however, these are non-modifiable factors. Environmental factors are key drivers of myopia progression and axial elongation over time, and ECPs can help minimize their impact by educating patients and their parents.

The first element to consider is time spent outdoors. Inform parents that at-risk children should spend at least one hour per day outside looking in the distance or playing sports.9 Some studies suggest allowing longer exposure to violet light (> 360nm) if children are provided with UV protection.10 Prescribed eyeglasses and UV filters should be adapted accordingly.

Time spent performing near work and the type of lighting used may also be contributors, although there is no positive correlation with myopia progression.11,12 Increasing reading distance to 40cm (15.75 inches) appears to reduce the risk of myopia progression, as does using incandescent light bulbs rather than fluorescent or light-emitting-diode (LED) lighting.

Parents should also monitor the time that their children spend using electronic devices. Some studies recommend no more than one hour per day.13,14 The old 20-20-20 rule, suggesting a shorter break of 20 seconds, does not seem sufficient to relax the visual system. This is important, because when a child plays on a tablet, there generally is no stop signal like the end of a chapter in a book. Too much time viewing at near is a challenge to the visual system, considering the reduced reading distance and the associated longer accommodative stress. Children should be instructed to take breaks from their tablets or smartphones after a certain period of time and for more than a few seconds.

Tablets and other electronic devices have not yet been proven as absolute contributing factors. Only one study established a link between computer use and the progression of myopia, but this study was conducted on an adult population.15 However, animal models suggest that chromatic aberrations may be associated with myopia progression. The theory is based on the fact that the brain prefers to focus on longer wavelengths and, consequently, the shorter wavelengths generate a central blur that stimulates eye growth.16

Our recommendations must, therefore, address reading distance, the use of electronic devices at near, time spent using tablets and smartphones, lighting of the environment, and other environmental factors that may need to be modified to create a more friendly environment for a child’s eyes.

STEP 3: INVOLVE CHILDREN AND THEIR PARENTS

Before spending time evaluating and managing myopia in young children, it is crucial to get their parents on board. They should understand the goals of your management strategy, and expectations must be shared.

One of the best ways to address this challenge is to provide appropriate and easily understandable documentation and to refer parents to educational, unbiased, non-commercial websites that explain myopia management, such as www.mykidsvision.org and www.myopiacare.org . In some cases, making this documentation available in a parent’s native language may be useful.

Have parents and their children sign a consent form that includes a section detailing their responsibilities as partners in this process. When parents and children are committed to the myopia strategy, compliance may increase. The practitioner-patient relationship expands so that they share the responsibility for the treatment. Children should understand the seriousness of the treatment that is being initiated in their best interests.

STEP 4: ASSESS BINOCULAR VISION

If improving environmental conditions represents the first pillar of a successful myopia management strategy, binocular vision status is the second. The binocular vision examination of a myopic or soon-to-be myopic child must assess vergences and accommodation.

Vergences are assessed with a prism bar (not behind the phoropter) at distance and at near. For near, it is important to evaluate phoria at a child’s habitual near observation distance, particularly if this is closer than 40cm. The near point of convergence is then recorded. Prism flippers can also be used if the child can easily compensate for a given deviation.

Myopia management will not succeed if binocular vision function, particularly accommodation, is altered or weakened.17 Perform your evaluation monocularly and binocularly. The first accommodative element to evaluate is amplitude, followed by flexibility, with the use of ±2.00D flippers. Next, measure lag or lead of accommodation at near with the retinoscope. Note that fixation disparity may be used instead. Also, evaluate negative and positive relative accommodation (NRA, PRA) amplitude. Finally, estimate the accommodative convergence/accommodation (AC/A) ratio.

The results from these tests will reveal binocular vision problems that need to be addressed. ECPs should make every effort to address clinically significant issues.

Binocular vision also will dictate the type of myopia management strategy to choose. Remember that switching from spectacles to contact lenses increases exophoria at near. If a child is already highly exophoric, check for reserves. If it’s impossible to restore the condition, it may be preferable to fit the patient with bifocal spectacles and add prism at near as needed. Another factor to consider is that any plus power placed in the system will first be used to compensate for accommodative deficiency.18 Again, it may be helpful to prescribe bifocal spectacles to wear over orthokeratology (ortho-k) or soft multifocal lenses to compensate for accommodative deficiencies.

STEP 5: PERFORM A CYCLOPLEGIC REFRACTION

The first refraction of a child who has myopia (or low hyperopia) must be performed under cycloplegia using cyclopentolate 1%. During follow-up evaluations, when myopia is confirmed, tropicamide 1% may be used instead.19

Full prescription of the cycloplegic refraction or autorefraction is recommended to alleviate central blur.20 Undercorrection of the refractive error is ineffective at slowing myopia progression; in fact, it has been associated with an increased rate of myopia progression.21 Regular and more frequent follow-up evaluations may be needed if the myopia progresses quickly. For example, if a child’s myopia today is –2.00D, and it is well-corrected optically and evolving at a fast rate, it will progress to –2.50D or –2.75D at three-to-six months and at nine months, respectively. (If the optical correction was not changed, the myopia would be undercorrected for most of the year.)

Refractive status and progression are relatively easy to establish when patients are wearing spectacles or soft contact lenses. With ortho-k lenses, however, it’s difficult to determine whether true myopia progression is present or whether our assessment is skewed because we are seeing the patient later in the day when the cornea is less molded, which results in a higher minus power. To determine whether there is progression in ortho-k, I measure visual acuity while patients are wearing the lenses. If the over-refraction is myopic, I suspect progression, which I confirm with a cycloplegic over-refraction while patients are wearing the lenses.

If progression is confirmed, the worst response is to fit a lens with a flatter base curve to compensate. Base curve is determined by corneal curvature, which does not change with myopia progression. Using flatter lenses increases the risk of corneal erosion and pushes the plus area beyond the pupil. Myopia management will be negatively affected, and myopia will progress at a faster rate. If significant refractive error (myopia or astigmatism) remains during the day, I correct it with spectacles. The molded cornea will still generate myopic defocus to manage myopia efficiently.

STEP 6: CONSIDER AXIAL LENGTH THE MOST IMPORTANT METRIC TO MONITOR

Axial length is the most important metric when managing children who have myopia or pre-myopia.5 Every child entering the practice should be evaluated for this parameter. As we observed, abnormal axial elongation precedes myopia onset at a younger age. When myopia is confirmed, axial length is the only metric that matters, as ocular pathology results from the elongation of the eye and not from its refractive power.22 If ECPs are serious about myopia management, they will acquire a biometer and monitor axial length in children at six- to 12-month intervals, starting at the age of 4.

Axial length correlates with eye power (diopters) in emmetropic eyes, but that is not always the case in myopic eyes. I have seen very long eyes that have small refractive errors and high myopes that have very short eyes. We should be more concerned about a –2.00D eye that has an axial length of 25mm versus a –6.00D eye that has an axial length of 23.5mm. The strategy to manage longer eyes will certainly be more aggressive, as the goal is to limit axial length increase to 0.1mm per year. Axial length measurement is not influenced by the ortho-k corneal profile,23 so ECPs can efficiently monitor progression without temporarily discontinuing ortho-k treatment.

STEP 7: SELECT YOUR TOOLS

Ideally, you should be able to offer all options necessary to meet the needs of your myopic patients. This starts with anti-myopia spectacles or prismatic bifocal spectacles, which are prescribed mostly to children who are intolerant of contact lenses or those showing high exophoria (not well compensated) at near. Another possibility is to add spectacles as an adjunct to contact lenses when accommodation is deficient.

Contact lenses are the gold standard of myopia management. Based on a meta-analysis, ortho-k and soft multifocal contact lenses offer similar levels of myopia and axial length control.24 This is a general statement, and the devil is in the details, as the lens design influences much of the outcome. It is possible to achieve no control with ortho-k lenses25 or limited control with soft multifocal lenses. Lens selection should start with two questions: 1) How much plus power do I need to generate effective myopic defocus? and 2) Where is this plus situated with the lens design I am using?

One study demonstrated that an add power of +3.00D is linked to more favorable outcomes.26 This does not imply that lower add powers are completely ineffective, but their impact is certainly reduced. Fast progressors may not be treated sufficiently with low-add-power lenses, particularly if they have accommodative dysfunction. Recently, another publication established that the optimal add power should be at least +4.50D.27 This study explains that ortho-k designs work better compared to soft contact lenses in higher myopes because of the increased plus power provided.

To understand the previous statement, remember that commercial ortho-k designs were mostly developed for myopia correction and not for myopia control. They usually generate an add power with a 1:1 ratio to the amount of refractive error corrected. According to this rule, a –1.00D correction will generate a +1.00D add zone. This may not be sufficient to efficiently manage lower myopes and those who progress quickly.28 We can improve this ratio by modifying and customizing the design with the help of available software programs. Customization also means controlling the central treatment zone. Limiting this zone will help bring more plus power within the pupil without negatively affecting other aspects of the treatment.29,30 Because the area of defocus is more important compared to the add power, this is an essential feature of a successful ortho-k fit for myopia management.31

Prescribing ortho-k lenses requires specific equipment. We cannot fit and monitor patients in ortho-k without a corneal topographer, which provides many essential functions. Axial or sagittal maps show the overall profile of the eye and the simulated keratometry (sim K) values. The tangential map is essential to monitor the impact of the lens on the cornea and its centration. The total power map shows the optical impact of the lens on the system; this is crucial to determine how much plus power is generated for a specific patient. The elevation map is mandatory to determine whether a lens with spherical or toric peripheries is needed. Eccentricity values are also essential pieces of data, particularly at the 7mm ring, where the lens usually lands. Visible corneal diameter determines the lens size. To manage myopia, we want to cover 90% to 95% of the cornea versus 75% to 80% when correcting refractive error only.

If customization of the ortho-k lenses is not possible, soft multifocal lenses are preferable for any patient who has less than 2.00D of refractive error. Also, patients who have a photopic pupil size smaller than 4.5mm will be better served by a soft multifocal lens with a design that is independent of pupil size (e.g., employs rings or extended depth of focus). Lenses should be center-distance designed. Center-near lenses generate negative spherical aberration (NSA) in the periphery, which promotes myopia progression and increases axial length.32 Conversely, center-distance lenses enhance the positive spherical aberrations (PSAs), which are considered protective against myopia progression. This may be the most powerful argument here: enhancing PSAs in lenses that generate the highest plus value possible.

In cases in which lenses with high add values induce blur at distance, some clinicians suggest over-minusing the distance refraction to re-equilibrate visual acuity. To me, this approach does not makes sense. Not only does over-minusing counterbalance the higher plus power, it will negatively affect treatment by overstimulating accommodation and convergence. While we wait for a new generation of myopia-control lenses to be introduced, I recommend using the highest plus power possible that does not generate blur at distance, without over-minusing the original cycloplegic refractive power.

STEP 8: PHARMACOLOGY MAY HELP

We don’t know how atropine influences axial length and myopia progression, but we do know that it may be an effective way to address this issue.5 As a standalone therapy, low-dose atropine was proven effective to freeze refractive error, but some studies proved that some concentrations generate unacceptable levels of axial length progression. The Low-Concentration Atropine for Myopia Progression (LAMP) study recommends the use of 0.05% atropine rather than 0.01% for this exact reason.33

When using contact lenses in cases in which myopia and axial length still progress at a faster rate than expected, consider introducing atropine 0.025% or 0.05% into the equation. Combined therapy has been proven more effective compared to monotherapy, likely because it increases the pupil area and, therefore, allows more plus power to reach the peripheral retina.34 This is particularly true if combining atropine and ortho-k lenses.

STEP 9: MONITOR AND COMMUNICATE WITH YOUR PATIENTS

Patients who have myopia should be closely monitored on a regular basis. This is more important at the beginning of the implementation strategy, regardless of the modality used to manage myopia. Not only can you make adjustments as needed, but this favors constant communication with parents and patients.

Compliance is one of the most important factors driving success. This is why, between visits, references to informative web sites, e-mails, or electronic communications from your office should keep parents and kids engaged and compliant.

STEP 10: MAKE IT A PROFITABLE JOURNEY

Myopia management takes time. It also necessitates acquiring new equipment and technologies that are not inexpensive. It may be necessary to revisit your fees and adapt them to this new reality. Your fees should reflect the time that you spend in the office with patients, and specialty lenses should be sold with a profit margin sufficient to help you acquire the new technology necessary to manage your specialty practice. Never undervalue your expertise in myopia management.

MYOPIA AS A PRACTICE BUILDER

Failing to control myopia promotes progression and can leave patients with a significant risk for eye diseases in the future. Ethically, every ECP should be concerned. We cannot stand idly by when 50% of the world’s population is becoming myopic, and 10% are at risk for severe ocular pathology. We all must work to counteract this.

You can adapt your practice and become a reference center for myopia management. It takes dedication, knowledge, teamwork, some new equipment, and, most importantly, a commitment to educate and inform patients about the importance of taking action. This is essential for the success of your practice. But, more importantly, it is necessary for the future of our youngest patients. CLS

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