Evidence-based medicine is the highest form of practice that ensures the best outcome for patients. As an eyecare practitioner, it is important to understand and utilize evidence-based medicine when choosing the right treatment for your patient.
Myopia control has come a long way since the beginning of the century in terms of scientific, evidence-based research. New data and treatments are constantly being published, providing eye doctors with a myriad of successful myopia control options.
The article below will provide an outline as to how to approach treating your myopic patient based on the latest, evidence-based research.
When to consider recommending myopia management
One of the most crucial steps when it comes to myopia management is understanding when treatment should be initiated/discussed with the parents. In the past it was not until the patient was already showing signs of myopia before intervention occurred. However, as a result of newer studies, we can now determine the likelihood of the patient becoming myopic based on a combination of age, refractive error, and axial length progression.
One of the goals of the Collaborative Longitudinal Evaluation of Ethnicity and Refractive Error (CLEERE) study was to determine the normal axial elongation during emmetropization in order to identify children that were likely to develop myopia. They found that normal axial elongation was approximately 0.1mm/year. Therefore, if a child was progressing more than this annually, they were likely to become more myopic, and practitioners should consider initiating myopia control treatment.1
Another important aspect of this study was to also identify the age and correlating refractive error cut-off point that would likely result in the child developing myopia. The authors found that children who have <0.50D at age 7 to 8 years, <0.25D at age 9 to 10 years, and emmetropia at age 11 showed a significant risk for myopia development and progression. The younger the children were when they developed myopia, the faster they progressed.1
The CLEERE study was a game-changing study in the myopia field in that it was the first study to provide doctors with evidence-based quantitative data that they could use to assess the risk of developing myopia BEFORE it developed.
In 2021, the International Myopia Institute recently released a comprehensive review of risk factors of myopia and supporting studies that can be used as a guideline for practitioners when considering myopia control treatment.2
Evidence-based approaches to myopia management
The current options for myopia management include soft multifocal/extended depth of focus contact lenses, orthokeratology, atropine (alone), and atropine combination therapies. All of these treatment modalities have been confirmed to be efficacious and safe from peer-reviewed research and therefore considered evidence-based therapies.
This section will provide an overview of the various and the major contributing studies.
Soft contact lenses to manage myopia
The Bifocal Lenses In Nearsighted Kids (BLINK) study by Walline et al. in 2017 was the first study to determine whether soft multifocal contact lenses (Biofinity multifocal) could be a potential way to slow myopia progression. The lens comes in a distance-center design, where the distance center is surrounded by peripheral hyperopic zones (add power +2.50D).
This lens design stems from the peripheral hyperopia defocus theory that the outer plus rings cause light to hit in front of the peripheral retina, signaling the eye to slow growth.3 The authors found a 50% reduction in the progression of myopia and a 29% reduction in axial elongation over a 2-year period.4 These results were both scientifically and clinically significant enough to be considered a viable myopia treatment option.
Years later, a new lens design was developed by Visioneering Technologies, Inc (VTI) to improve upon the Biofinity multifocal with the aim to slow myopia progression even more so. The NaturalVue lens is different in that instead of rings of add power it has an extended depth of focus with gradual increase plus power (up to +3.00D) and a wider range of clear vision from distance to intermediate to near.
A study by Cooper et al. from 2018 found nearly twice the reduction in refractive error and axial length compared to the BLINK study.5 Although these are impressive findings, it is important to note that this was a retrospective study, whereas BLINK was a prospective, randomized, double-masked study.
MiSight contact lens to manage myopia
The MiSight lens is the first FDA-approved myopia control lens. It is a dual-focus soft lens that created a simultaneous defocus in front of the retina (distance and near), and a clear image at the retinal surface. In a double-randomized, double-masked clinical trial, authors found that mean myopia progression and axial elongation slowed by approximately 50% after 3 years with the MiSight lenses.
Even after 6 years of follow-up, subjects did not show any clinically meaningful progression in myopia.6 This is so far the longest-running soft multifocal study and therefore provides strong evidence of its long-lasting efficacy.
Orthokeratology to manage myopia
This lens was originally used to correct myopia in patients, not slow progression. However, when clinicians found that their patients were not progressing as rapidly when fit with these lenses, scientists explored the use of orthokeratology (ortho-k) for myopia control. The orthokeratology lens has the same material and rigidity to gas-permeable lenses; however, it is a reverse geometry lens design intended to flatten the cornea during nighttime.
When the lens is removed upon awakening, the cornea is molded, and the patient can see clearly without correction. Furthermore, researchers discovered that similar to the soft multifocal contacts, light was also focused in front of the peripheral retina, signaling the eye to slow growth.
Two studies, the Children’s Overnight Orthokeratology Investigation (COOKI) study from 2004 and Longitudinal Orthokeratology Research in Children (LORIC) study from 2005, both found that orthokeratology was a safe and effective treatment for myopia control.7,8 In the Retardation of Myopia in Orthokeratology (ROMIO) study, authors found that younger children (<7 years) showed a trend toward faster myopia progression and axial elongation. Children then fitted with ortho-k lenses demonstrated a slower change in axial elongation compared to those wearing single vision glasses.9
Atropine to manage myopia
Atropine is a non-selective muscarinic acetylcholine receptor antagonist that is believed to target the retina and inhibit myopia progression.10 Although this is not a proven mechanism of action, what has been proven by multiple studies is that atropine is effective in slowing myopia progression. The Atropine for the Treatment of Myopia (ATOM) studies were the first major studies that evaluated the effectiveness of atropine.
The ATOM 1 study compared the use of 1% atropine in one of the subject’s eyes compared to the other eye (served as the control). The 1% atropine was effective in slowing myopia control for both refractive error and axial length. However, there were significant side effects, such as blurry vision and reduced accommodation. Also, when the study authors discontinued 1% atropine after 2 years and followed subjects for another year, the eyes started to progress at the rate before atropine was started.11
Due to the significant side effects of 1% atropine, the ATOM 2 study was created to establish the safety and efficacy of various lower levels of atropine concentrations (0.01%, 0.1%, 0.5%, and 1.0%). The authors determined that 0.01% atropine subjects showed nearly the same amount of diopter progression as 1% but without the side effects associated with 1% atropine.12
The Low-Concentration Atropine for Myopia Progression (LAMP) study built upon the ATOM 2 study by testing 0.01%, 0.025%, and 0.05% atropine concentrations. Interestingly, they determined that 0.05% was the most effective concentration of slowing diopter and axial length growth with minimal side effects. This study was important since many practitioners were able to safely increase the dosage of atropine if 0.01% was not effectively reducing myopia progression in patients.13
Currently, the ATOM group is working on a study the explores the effects of 0.01% atropine for pre-myopes and low myopia in order to determine if early prevention is clinically beneficial for patients.14
Atropine combination therapies to manage myopia
Recent studies have been evaluating the effect of combining atropine with other myopia control treatments. In 2020, Tan et al. found a synergistic effect of combined therapy that plateaued at 6 months.15 That same year, Kinoshita et al. exhibited a significant reduction in myopia progression for children with 1 to 3D of myopia but not 3 to 6D.16
The Bifocal and Atropine Myopia Control (BAM) study is currently investigating the combined effect of 0.01% atropine and soft multifocal distance-center lenses. It is the first prospective study performed in the US, as all other studies were performed in East Asia.17 Combination therapies may become part of current myopia control treatments in the near future as more data is obtained and will allow practitioners to tailor their treatments.
Spectacles to manage myopia
The jumpstart to the “myopia control wave” occurred thanks to the famous Correction of Myopia Evaluation Trial (COMET) study. The authors studied the effect of progressive lenses (PALs) in nearly 450 children over at least 3 years. They found a statistically significant but not clinically significant difference in myopia progression in the PAL vs. single vision lens (SVL) group. They also found that PALs worked better for children who had a high lag of accommodation or esophoria at near.18
After the COMET study determined that PALs were ineffective, many researchers and clinicians moved away for spectacles as a myopia control treatment option. It was not until nearly 20 years later that new spectacles designs were developed and tested.
Myopia-correcting spectacles from Zeiss and Essilor
Zeiss developed a lens known as Myovision. The design of this lens is a distance center with a peripheral plus (either +1.00 or +2.00). A study from 2018 by Kanda et al. found a 20% reduction in refractive error change in Chinese children ages 6 to 12 years, but no significant reduction in axial length.
Essilor designed the Myopilux Max, which was essentially an executive bifocal with an add power of +1.50D and/or 3D base-in (BI) prism. Their research team compared single vision lens group to an executive bifocal group with an add power of +1.50D and/or 3D BI prism.
Both bifocal groups showed a significant reduction in refractive error compared to the control group. Children with higher lags of accommodation showed similar results with bifocals with and without prism. Conversely, children with lower lags of accommodation showed a greater treatment effect in prismatic bifocals compared to regular bifocals.20
Myopia-correcting spectacles from Hoya
The MyoSmart lens is manufactured by Hoya. The lens is a unique design that consists of a 9mm central optical zone surrounded by multiple focal zones of relative plus power. In a 2020 randomized controlled study by Lam et al., the authors found a 52% reduction in myopia progression and a 62% reduction in axial elongation compared to control groups.
One of the most promising lenses is based on a Highly Aspherical Lens Technology (HALT) design that consists of a constellation of aspherical lenses spread over 11 rings. A 3-year study is currently underway studying the effects of this lens in myopia control. The first-year results demonstrated a reduction myopia progression by 60% and axial length elongation by 28%.22
Red-light therapy
Red-light therapy is a relatively new myopia control treatment that has been studied the last couple of years. Researchers theorize that exposing children to red light could have potential slowing effects on myopia.
A 2023 study by Dong et al. investigated the safety and efficacy of red-light therapy in slowing myopia progression compared to a sham device with only 10% power. Children followed a schedule of 3 minutes per session, twice daily, with an interval between sessions of at least 4 hours. The authors found that the red-light therapy at 100% power significantly reduced myopia progression over a 6-month period.
A 2022 study by Jiang et al. found a significant reduction in refractive error and axial length after 12 months with no structural damage.24 Further studies with longer follow-ups are needed to determine if this is truly a clinically effective treatment.
When to monitor and adjust myopia treatment
The International Myopia Institute created a Clinical Management Guidelines Report with recommendations for management schedules depending on treatment type selected.25 They determined that after initiating treatment, patients should be followed 1 week, 1 month, 3 months, and 6 months after treatment.
Additionally, every 6 months, cycloplegic refractions and axial length measurements should be performed. These are, however, just guidelines, and doctors should adjust their follow-up schedules for each individual patient.
How do we know if the treatments are actually working?
One way is to look at the axial length progression. Based on the CLEERE study, it was determined that before age 10, the normal axial length change in emmetropizing children ranges from 0.1 to 0.2mm/year. After age 10, a change of 0.1 mm/year or less is normal.
Furthermore, any refractive error >0.50D change per year is not considered normal.26 Therefore, if you see axial length changing more than 0.2mm/year or refractive error >0.5D/year it may be time to consider another/combination therapy.
How do we know whether to switch/combine treatment modalities?
If the current treatment is not slowing myopia progression and axial length by the desired effect, as stated above, it may be time to switch to another modality or consider combination therapy with atropine.
For example, if the practitioner cannot achieve 20/30 vision in either eye or refractive change <0.50D/year with the best fitting orthokeratology lens, they should consider switching to soft lenses or spectacles, or add a low dose atropine therapy to their regimen.27
If this is still not effective, consider switching to a higher dose atropine, such as 0.025% or 0.05%. Since combination therapy studies are still in their early phases, it is important to monitor the patient closely.
Deciding when to discontinue myopia treatment
Unfortunately, studies have not obtained enough conclusive data as to what age is appropriate to discontinue myopia control. What we do know is that stabilization of myopia is believed to occur around early to mid-20s.28
Under the International Myopia Institute, researchers have come to a consensus that if the patient’s refractive error shows <0.25D change over a 1- to 2-year period, progression is likely minimal, and the practitioner can consider discontinuing treatment.25
After discontinuing treatment, it is important to monitor refractive error and axial length monthly for the first year to check for a rebound or accelerated “catch-up” rate that would offset the myopia control gains.29
In conclusion
Myopia control is a relatively new type of treatment that has gained traction in the last couple decades. It is important for practitioners to understand the evidence-based science behind these treatment options so that they can provide the safest and most effective treatment for their patients.
Since new treatments are constantly emerging, doctors should continue to stay up-to-date on the latest research and adjust their treatments based on new technologies and protocols. Online forums, such as Eyes On Eyecare and Myopiaprofile.com, provide an excellent resource for practitioners.
