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The efficacy of orthokeratology (Ortho-K) relies on the precise mechanical manipulation of the corneal epithelium.

Ortho-K lenses are designed with a "Reverse Geometry" profile, featuring a central treatment zone that is flatter than the cornea and a peripheral return zone that is steeper.

When worn during sleep, the lens does not physically "crush" the cornea. Instead, it creates hydraulic forces within the tear film trapped between the lens and the eye. These forces induce a redistribution of epithelial cells: cells migrate from the central cornea (where pressure is highest) toward the mid-peripheral return zone (where pressure is lowest). This results in a central thinning and mid-peripheral thickening of the corneal tissue.

This redistribution effectively changes the refractive power of the eye, focusing light directly onto the retina to correct myopia. The effect is temporary because the epithelial cells eventually migrate back to their original positions once lens wear is discontinued.