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A third approach, called orthokeratology, involves wearing contact lenses at night to change the shape of the cornea, make the edges of the eye more farsighted and perhaps slow the eye’s elongation.

Orthokeratology lenses—hard lenses prescribed for use at night to flatten the cornea to decrease nearsightedness—also can increase the risk of infection, Dr. Rapuano says.

Now optometrists like Dr. Liu are offering a treatment called orthokeratology — ortho-k, for short.