Currently, there are multiple options to slow myopia, including progressive addition lenses, multifocal contact lenses, peripheral defocus spectacles, multi-segment spectacles, orthokeratology, and various concentrations of atropine. However, at an individual level, a patient and their caregiver are mostly concerned about whether a chosen option effectively controls their myopia. It requires that the practitioner provide information on whether a specific option would help their circumstance and, once the treatment begins, to provide feedback on its performance. In this regard, certain infographic tools, such as MyopiaProfile.com, are useful in gauging success on an annual basis.¹ However, the progression estimates in such infographics are averaged to an age group of 3- to 5-year-olds, which could be a limitation to a patient needing more precise age-specific estimates. 

In myopia management, commonly used outcomes that measure the success of treatment are change in spherical equivalent (sphere + cylinder/2) and axial length elongation. ^2,3 Unlike treatments for other ocular disorders such as cataract and glaucoma, where efficacy can be measured within weeks, myopia treatments usually require a much longer follow-up, possibly a minimum of a year, as seasonal variations have also been found to affect progression.

Spherical Equivalent (SE)

The use of SE to monitor progression has the advantage of being a functional endpoint that translates to quantifiable prescription changes for the patient. However, SE progression is significantly affected by patient factors such as age, ethnicity, baseline refractive error, and, to a smaller extent, by parental myopia and gender. Therefore, quantifying efficacy at an individual level requires an understanding of progression relative to these demographic factors. For example, an annual SE progression of approximately 0.50D in a young Asian child wearing single-vision spectacles may be expected. In contrast, a similar rate of progression in a Caucasian child may indicate faster progression.  

A simple tool based on progression data from myopic kids and meta-analyzed ethnic differences is the BHVI myopia calculator.⁴ It provides progression estimates and confidence bands based on ethnicity, starting age, and refractive error, and it is a starting point to evaluate efficacy. Once a myopia management treatment strategy is chosen, the calculator then generates an additional curve based on expected efficacy. This estimate is a group estimate that applies across the entire age range and is provided as an indicative guide for efficacy.

How can this information be used? For example, a Caucasian child aged 8 years, -0.50D without myopia control is estimated to progress to approximately -1.10D at 9 years and -1.60D at 10 years. In other words, the progression is -0.60D and -0.50D for the first and second year, respectively. This may then be used to compare the individual’s observed progression as set out in table 1, where progression is measured as change in SE from starting age (8), “Absolute efficacy” is the observed – expected difference in SE progression, and “Efficacy %” is absolute efficacy / expected progression.  A negative percentage indicates the efficacy of myopia treatment. The Efficacy % can be compared to published data and tracked over time.

Table 1. Caucasian child, 8 years old, starting RE: -0.50D.