Our eyes must be in focus for us to see accurately, just as a camera must be in focus to obtain a clear picture. Light, which gives us vision, is focused largely by the eye's front surface or cornea. OrthoK (short for orthokeratology) gently molds or focuses the cornea while a person is sleeping, creating a sharpened image when they wake.
Your doctor will design the OrthoK mold to obtain the change needed to achieve clearly focused vision. When the lens is removed in the morning the cornea begins to return to its original shape but so slowly that good vision is maintained all waking hours. Each night the process is repeated although some find they only need to wear their molds every other night.
The elastic tissue of the eye is not harmed by this daily process. Perhaps an analogy that most of us have seen would be the ridges formed on the ankles by a snug fitting pair of socks. The ridges eventually go away and the tissue remains healthy.
OrthoK is reversible. It is not a permanent alteration of tissue and thus is an excellent Lasik alternative for those reluctant or unable to undergo a surgical alteration of their corneas.