Abstract: Contrast is defined as the ratio of the light intensity of a target to that of its background. The contrast theory posits that contrast signals are a critical regulator of ocular axial growth, and excessive high-contrast visual signals can trigger the onset of myopia. High-contrast signals can abnormally activate the retinal ON/OFF pathways, which in turn causes dysfunction of the dopaminergic system, resulting in choroidal thinning and reduced choroidal blood flow, and ultimately leading to hypoxic scleral remodeling — the fundamental pathophysiological change driving the onset and progression of myopia.In recent years, diffusion optics technology (DOT) based on the contrast theory has been proposed. DOT lenses developed with this technology can reduce high-contrast signals impinging on the retina solely through their micro-scattering structures, thereby slowing axial elongation and controlling myopia progression, with a favorable safety profile and excellent tolerance of visual function. However, existing studies are mainly limited to short-term evaluations, and the long-term efficacy and rebound effect of the lenses remain to be further verified.

Key words: Myopia control, Contrast theory, Diffusion optics technology