Is switching the myopia control strategy necessary if there is myopia progression?

What do you do when your patient still progresses at a significant rate despite you starting myopia control treatment? At this point, it may be tempting to switch treatments. PC shared this case with the Myopia Profile Facebook group that illustrates this precise dilemma. When should you switch treatments or continue?

Firstly, let's evaluate the reported success of the prior orthokeratology (OK) treatment, and of myopia management so far for this child. Here's what we know.

1. The child was fit with OK at around age 8.
2. She had progressed around -2D in the year prior to OK fitting
3. The typical progression per year for a single-vision corrected child of that age is around -1D,1 indicating that she is progressing faster than average. For a useful reference table on typical annual progression in single vision corrected children, download the Johnson & Johnson Vision Managing Myopia Guide (Table 5 on page 8).
4. The child progressed by -1D in a year wearing OK. Given that this is about the average annual progression for a single-vision corrected child of the same age, this could be considered an unsuccessful treatment outcome.
5. The treatment was judged as unsuccessful, so the child was discontinued from OK and changed to multifocal (progressive addition) spectacle lenses. This represents a change to a less effective treatment.²
6. In the three years since discontinuation of OK, she has progressed by -2.50D in her right eye and -3.00D in her left eye.

This child is now a high myope with an axial length over 26mm, which increases her lifelong risk of vision impairment.

There are two ways to look at this child's treatment success in OK, before the management method was changed.

• When comparing her prior progression to the currently observed progression (-2D per year before to -1D in the year wearing OK), this appears to be successful. This is partly true, although prior progression isn't necessarily the best judge of future progression, and myopia progression typically slows with time as children get older.²
• When comparing her observed progression to the average observed for a single vision-corrected child of the same age (-2D per year before OK compared to around -1D per year)1 then we can identify this child as a faster progressor, such that the 'average' results may not be achieved for that child.

Considering this patient's faster-than-average progression at the outset, it would have been useful to explain this to the parents and patients in setting expectations, and this could have led to continuation of OK wear. It was not an effective choice to change this patient to multifocal (progressive addition) spectacles, which show lower efficacy than OK.² 

The patient's myopia progression since discontinuing OK could represent a rebound effect,² as well as indicating faster progression than a typical single-vision corrected, aged-matched child¹ - a continued, unsuccessful treatment.

When prescribing myopia control treatment, it is important to remember that the expectation is not to completely halt progression. It is normal to still have some degree of progression at a reduced rate that is hopefully similar to what you might expect from average rates of reduction as suggested by the literature for the various modalities. In the case of this child, their progression prior to myopia control intervention was faster-than-average, so their progression when in a myopia control treatment could similarly be expected to be above average. What else could be done? Here were some suggestions.

It is important to consider what treatment option provides effective myopia control as well as being suited to the patient's goals for their myopia correction. The Johnson & Johnson Vision Managing Myopia Guide states that "Knowing efficacy is similar across treatments, it is most critical that the treatment regimen fits the patient's lifestyle, expectations, motivation and their abilities."

Firstly, could they have stayed in OK? if the patient was achieving good myopia correction with OK, despite the apparently unsuccessful myopia control result, did they need to be changed from OK? Understanding that this child was likely a faster-than-average progressor at the outset, and appropriate setting of expectations that an 'average' result may not occur, is a key learning in this case.

If the child progressed to a point where OK was no longer feasible as a myopia correction, as mentioned above, multifocal or myopia controlling soft contact lenses could have instead been an option. There is also evidence from one study for partial-correction of high myopia with OK, topped up with single vision distance correction for the residual refractive error, as an effective myopia control strategy.³

Secondly, there are additional benefits to children wearing contact lenses. Improvements in children's confidence, satisfaction with their vision correction and functional ability to participate in more school and sport activities occurs when they are switched from spectacles to contact lenses.⁴

Thirdly, additional efficacy could be gained by adding atropine to OK. Although the evidence is early, there is indication that OK combined with atropine could be beneficial,⁵ although the most recent two-year study showed 0.01% atropine increased myopia control efficacy in 1-3D myopes only, as the 3-6D myopes progressed less overall.⁶

Finally, monitoring axial length can better gauge progression. Where possible and available, axial length measurement can detect changes in myopia progression with up to 10 times more accuracy than refraction.⁷ The Johnson & Johnson Vision Managing Myopia Guide also provides guidance for judging a child's annual axial length progression against age-matched norms.

1. When myopia control treatment doesn't give the efficacy you expect or hope for, avoid the temptation to switch treatments completely and consider the expectations for that patient. References are available to help judge whether your patient is an 'average' progressor and such if 'average' results are likely to apply. This is important in both setting goals and gauging myopia control success along the way.
2. Orthokeratology has a superior myopia control efficacy to progressive addition spectacle lenses. Changing to a less effective strategy is never an ideal option, and rebound effects could also factor into any discontinuation of myopia control treatment.
3. Better strategies to increase myopia control efficacy would have included adding atropine to OK. If continued myopia progression meant full OK correction was no longer suitable, partial OK correction with top-up spectacles would likely still give superior results to progressive addition spectacle lenses.

• Why isn't the myopia control strategy working?

• Case study: When a patient doesn't respond to orthokeratology

• Case study: Can we reconsider contact lenses?

• How can we set myopia control expectations?