Myopia progression is best predicted by age, with younger onset associated with faster advancement and, eventually, higher levels of myopia. Myopia control alternatives should be explained to parents of any myopic child, but especially those under the age of 12. Myopia mitigation should be prioritized for children presenting with the following risk factors: parental myopia, reduced time outdoors, East Asian ethnicity, less than age expected hyperopia and female gender.
Unfortunately, there is insufficient evidence that any myopia control treatments will be effective in slowing cases of pathologic myopia. Pathologic or degenerative myopia is defined as the presence of structural changes due to axial elongation in eyes with high myopia. Fortunately, most children develop what’s often known as “school age” myopia, which is generally well-managed with current myopia control treatments.
The average age at which myopia usually stops progressing is 15 to 16 years. About 10% of myopes will progress beyond the age of 21 years. Researchers are beginning to evaluate over five years of data from a few new studies, and have come to expect some lessening of myopia control efficacy over time. But, cumulatively, children will still gain benefit from myopia control treatment over traditional single-vision spectacle correction for as long as their myopia continues to progress. Stopping treatment may be considered when the myopia progression rate slows, which is usually when children reaches late adolescence. However, close monitoring is mandatory in managing these patients. If myopia progression is detected, restarting treatment is advisable. Parents should be educated about the costs and benefits of continued treatment and assisted to make an informed decision via the use of cycloplegic autorefraction and axial length measurements to monitor progression.
There is clear evidence from randomized clinical trials that increased outdoor time can delay the onset of myopia, and thus decrease the final amount of myopia a child develops. Increased outdoor time may also have a small protective effect in slowing myopia progression. Greater duration of near work and close working distances have been associated with increased risk of myopia. A recent observational study provides some suggestions that a closer working distance may also be associated with increased progression. Other possible risk factors include use of LED lamps for homework, dim light, fewer hours of sleep and living in an urban environment.
The same factors that are related to onset are likely related to progression, but further research is needed to fully understand the interplay of genetic and environmental factors in both onset and progression. For now, the potential benefit and very low cost and risk associated with outdoor time and breaks from close near work make them ideal goals for pre-myopic and myopic children. This means limiting cell phone and tablet use as much as possible.
Recent evidence, together with changes found during COVID-19 lockdowns demonstrates that behavior changes related to digital devices may indeed worsen myopia in youngsters. Although more high-quality research is needed to prove causation, optometrists caring for children at risk should evaluate the possibility that excessive smart device use could lead to an increase in myopia. The recent global growth in myopia prevalence predates the advent of digital devices. However, this result does not rule out the likelihood that such devices would have an impact on future myopia trends.
2019 brought FDA approval of the first contact lens specifically developed to slow the progression of nearsightedness, CooperVision’s MiSight lens. With an excellent efficacy and safety profile, this daily disposable lens is a great choice for any child within the available parameters.
The foundation of evidence-based care is to provide patients with all of the appropriate options for which they are a candidate and to assist them in making an informed decision in their care. There is much evidence to demonstrate that other soft multifocal contact lenses, orthokeratology, and atropine can also slow myopia progression. Recent studies have also demonstrated that executive bifocals (lenses with a line across the entire lens) can have a smaller, but still clinically meaningful, effect in slowing progression. There are many appropriate reasons why patients may prefer to start with one treatment over another. These include cost, patient compliance, current prescription and any binocular vision anomalies.
Preventive measures such as increased outdoor programs and activities and changes on limiting near distance activities in preschool children should be implemented. These are cost effective and relatively easy to administer.
CooperVision has released findings from a two-year clinical study for its Diffusion Optics Technology, which is aimed to help children reduce the progression of myopia. According to a recent press release, children who wore their Diffusion Optics Technology-enabled spectacles full time for two years, including not removing them for near vision activities, progressed one-half diopter less than those who wore the control spectacles—a drop of 59 percent. Beginning this month, CooperVision will make the new product available to eyecare providers in the Netherlands. This technology is currently unavailable in the United States.
MiSight is a center-distance design with a +2.00 D add. If there are concerns with cost, or the need for astigmatic correction, the CooperVision Biofinity spherical and toric multifocals with a center-distance design and a +2.00 or +2.50 add would be good evidence based off-label options. NaturalVue multifocal contact lenses are another good choice with center distance design and a wide range of available parameters. There are intriguing hypotheses about how to modify the central treatment or mid-peripheral zones, but no solid evidence that any of the different orthokeratology designs offer superior myopia control efficacy. Thus, any orthokeratology lens design can be used for myopia control. Recent data on executive bifocals demonstrated good efficacy with a +1.50 add, but a higher add (e.g., +2.50) would also be a valid evidence-based treatment.
A recent trial showed that 0.05% atropine was the most effective in controlling both axial length and refractive error progression, and should be the starting point for drug treatment.
While multiple studies are underway to explore the combination of drug and device treatments, we still lack sufficient evidence about when to add another treatment or when to switch treatments. Unfortunately, there is no way to determine which treatment will be most effective for which children. Online calculators may overestimate the myopia control effect, but current work aims to develop standard “ocular growth curves” that may help better determine whether a treatment is effective.
Until then, the best treatment plan includes regular monitoring of cycloplegic autorefraction and axial length, and discussions about general expectations for progression (i.e., 0.50 to 1.00 D/year). Due to expected seasonal variations in progression, it’s not recommended to change treatments before at least a year, unless there are issues with intolerance or noncompliance.
Some of the most challenging patients are those with higher myopia, astigmatism, or binocular vision issues, as these are overlooked areas of research. Parents of young children with high myopia should be counselled about potential genetic causes. If parents still elect treatment, doctors should carefully educate and document lowered expectations for efficacy.
Children with more than 1.00 D of astigmatism may not have sufficient acuity with the MiSight lens and may be better served with a soft toric multifocal. Generally, orthokeratology is more successful with less than 1.75 D of with-the-rule astigmatism, and when the astigmatism is not greater than the myopia. Bifocal glasses and atropine are options for nearly any refractive error. Children can become more exophoric with multifocal or orthokeratology lenses. Children who are exophoric or demonstrate signs of convergence insufficiency should be questioned as to any symptoms and treated for their binocular vision disorder prior to initiating myopia control since treatments may exacerbate underlying conditions.