Combination therapy
In the study that defines this row, the two mechanisms together outperformed either one alone. Combining them is the most intensive control strategy in this synthesis: neither optical defocus nor red light on its own reproduced the combined effect.
Adjusted mean yearly axial change was −0.13 mm with combination therapy, against −0.04 mm for red light alone and +0.16 mm for defocus lenses alone (p < 0.0001). Spherical equivalent moved +0.09 D in the combined group while both monotherapy groups progressed. No adverse event was observed or reported in any of the three groups.
A retrospective cohort with no single-vision control arm and unbalanced group sizes, adjusted through a mixed model. Cycloplegia was not performed at every visit, so the refractive figures can be confounded. The authors call for randomised trials to validate the synergy.