Refractive astigmatism is prevalent at birth and decreases as eyes undergo emmetropization during their first few years. For children who have clinically significant astigmatism (> –0.75D) that persists beyond 5 or 6 years old or that continues to increase in the presence of progressing myopia, our toolbox becomes very limited; almost all recent randomized controlled soft multifocal studies supporting myopia control utilized spherical multifocals, with maximum cylinder of 1.00D or 1.50D for participant inclusion criteria (Wolffsohn et al, 2019).

Statements of Fact

The following evidence-based statements support the potential use of commercial multifocal hybrid designs in progressing myopic astigmats:

1. Undercorrection of refractive error has no clinically significant benefit in slowing myopia (Wolffsohn et al, 2019) and may even lead to faster myopia progression (Chung et al, 2002; Adler et al, 2006). When a spherical soft multifocal lens is used as a means of optical correction for a patient, any residual toric prescription means that an optical meridian at the retinal (foveal) plane will experience defocus. This still qualifies as a form of undercorrection and may lead to faster progression of myopia than anticipated. When this residual astigmatism is mainly due to corneal astigmatism (Figure 1), the tear lens created by the GP center of a hybrid lens can provide optimal correction of central vision, thus mitigating this risk.

   

2. Reducing relative hyperopic defocus at the peripheral retinal plane signals an eye to slow down its axial, and subsequent refractive, growth (Wildsoet et al, 2019). This finding has prompted researchers to evaluate the role of lower versus higher add powers in simultaneous-design multifocals on slowing the progression of myopia; they hypothesized that greater peripheral plus power in the lens leads to better control of myopia. Although children may not be able to tolerate add powers higher than 2.50D due to significant decreases in optical quality, multifocal hybrid lenses with center distance optics can be designed with add powers as high as +5.00D.
3. Children have different pupil dynamics in ambient light compared to adults. Despite this, practitioners still fit lenses designed for presbyopic eyes on the eyes of young patients who have progressing myopia (Wildsoet et al, 2019).

The center-distance zone in multifocal hybrid lenses can be manufactured from 1.8mm to 4.0mm in size. While a larger central zone may optimize distance visual acuity, a smaller central zone size may be more effective at projecting the surrounding plus power to the retinal periphery via the larger pupil size of children under photopic lighting conditions (Figure 2).

In Conclusion

Theoretically, the answer to the title question is yes. Multifocal hybrid lenses appear to have all of the right components to slow myopia in progressing myopic astigmats. However, there is currently no randomized controlled research that evaluates their ability to do so. An exploratory study would be useful to answer outstanding questions on the ability of that lens modality to enter the arena of myopia control options, albeit an off-label use in this category. CLS

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