Who is ortho-k for?
Ortho-k is mainly used to correct near-sightedness (myopia). This vision problem can also usually be corrected by eyeglasses, regular contact lenses, LASIK or PRK. Orthokeratology is a surgery-free way for some people to leave their glasses behind and not have to wear contact lenses all the time.
Ortho-k is sometimes recommended to correct children’s vision. Vision can continue to change for some children into adulthood and their 20’s. Vision correction surgeries like LASIK are not recommended until vision is stable. There is no firm evidence that ortho-k can slow down the progression of myopia in children, but this is also being studied as a possibility.
How does ortho-k work?
The cornea is a clear, dome-shaped window in the front of your eye that focuses light onto the retina and is responsible for most of the eye’s ability to focus. Its tissue is very flexible.
Your optometrist will map and measure the surface of your cornea using an instrument called a corneal topographer and then design a lens, especially for your eye. The cornea map is created by reflecting light off the surface of the eye. The machine doesn’t touch your eye, and there is no pain. The corneal topography map shows your optometrist the shape and curves of your cornea.
The lenses work by flattening the center of the cornea, changing how light is bent as it enters the eye. Most orthokeratology lenses are worn overnight to flatten the cornea, then removed during the day. These overnight lenses are rigid, gas-permeable lenses that are sturdy enough to reshape the cornea, but also allow oxygen through so your eye stays healthy.
When ortho-k lenses are removed the cornea stays flattened for a while and vision is corrected without the need for glasses. If you stop wearing the lenses at night, your eyes will eventually go back to their original shape and the refractive error will return. You have to keep wearing the lenses regularly to keep the vision correction.