August 1, 2024
By Dwight Akerman, OD, MBA, FAAO, FBCLA, FIACLE
To determine the success of any juvenile-onset myopia intervention, it is vital to consider the target for myopia progression management. Is the treatment goal to stop axial length growth or simply slow progression? How should axial length growth in children undergoing myopia management treatment be compared to average eye growth in emmetropic children of the same age? What treatment effect is required to be considered clinically meaningful? Most myopic children, especially those of East Asian ancestry, in the age range of 6-10 years old, if untreated, will manifest axial elongation ~0.30 – 0.40 mm per year.
A successful intervention for a child under 10 years old, typically showing axial elongation greater than 0.30 mm per year without treatment, would have a clinically meaningful outcome if annual progression can be slowed to less than 0.30 mm. It would be an exceptional outcome if annual axial length progression could be slowed to less than 0.20 mm, the rate at which typical emmetropic children of the same age progress per year. In myopic children older than 10 years, who typically show an average axial elongation of 0.20 mm without treatment, a clinically meaningful outcome of myopia intervention would be if axial length progression can be slowed to less than the untreated average. Slowing axial length elongation to 0.10 mm per year or less would be an exceptional outcome for adolescents, as typical emmetropes of the same age demonstrate this axial elongation rate.
However, not all children are average. Some children may be faster progressors, and others may be poor respondents. These children may require combination therapy to achieve intervention goals.
Combination therapy in myopia management has been a growing area of interest among researchers and eye care practitioners. Over the past few years, numerous studies have been conducted to investigate the potential additive benefits of combining different treatment modalities for addressing juvenile-onset myopia. These studies have explored the combination of various approaches, such as atropine and orthokeratology, atropine and soft multifocal contact lenses, as well as atropine and next-generation myopia control spectacles.
One of the key findings in the research is the potential synergistic effects of combining 0.01% atropine with orthokeratology. Atropine, with its antimuscarinic effects, and orthokeratology, through peripheral hyperopic defocus, are believed to work through different mechanisms. Therefore, it was theorized that these two mechanisms could potentially work together to slow myopia progression. Studies have shown promising results in the combination of atropine and orthokeratology, with a significant slowing in axial length observed in the combined group compared to monotherapy. However, the duration of the effects and the specific patient populations that benefit from this combination therapy require further investigation.
Additionally, there have been studies that examined the combination of 0.01% atropine with soft multifocal contact lenses (+2.50D Add.) While the potential benefits of these combinations were initially of interest, the results from these studies did not demonstrate significant advantages of adding atropine to multifocal contact lens therapy. This suggests that the effectiveness of combination therapy may be influenced by the specific modalities involved and the individual characteristics of the patients.
Moreover, the combination of atropine with myopia control spectacles has also been explored. Research in this area has shown variable results, with some studies indicating a reduction in refractive error but not in axial length, while others have reported significant differences in both axial length and refractive error compared to monotherapy. The differences in these findings may be attributed to the characteristics of the patient populations studied, highlighting the need for further research to understand better the factors that contribute to the effectiveness of combination therapy in different groups of patients.
It is worth noting that while some of these studies have demonstrated significant benefits of combination therapy, the results are often based on a relatively short time frame and involve subjects with low to moderate myopia. Therefore, there is a need for longer-term studies to determine the actual and sustained benefit of combination therapy across different patient demographics and myopia severity levels. Future combination studies may focus on higher concentrations of atropine, such as 0.05% atropine, to effectively control myopia in individuals with high myopia, fast myopia progression, or poor responders.
Despite the need for further research, it is important to acknowledge that no significant adverse events have been reported by combining different myopia management therapies. This suggests that combination therapy is generally safe and may be an option worth considering, particularly for patients who are not achieving the desired results with monotherapy. However, given the potential variability in treatment outcomes, it is essential for eye care practitioners to carefully assess each patient’s unique characteristics and response to different treatment modalities when considering combination therapy.
In conclusion, combination therapy in myopia management holds promise as a potential approach to address the growing prevalence of myopia worldwide. While the findings from existing studies are encouraging, there is a clear need for further research, particularly long-term studies involving diverse patient populations, to fully understand the effectiveness of combination therapy and its specific applications in clinical practice. By continuing to explore and refine combination therapy approaches, eye care practitioners can enhance their ability to provide personalized and effective myopia management strategies for their patients.
Best professional regards,
Dwight H. Akerman, OD, MBA, FAAO, FBCLA, FIACLE
Chief Medical Editor
dwight.akerman@gmail.com
