If your eye care professional feels you are a good candidate for orthokeratology, you will wear specially designed GP (gas i.e. oxygen permeable) lenses at night only. In the one- to two-week treatment phase, your nearsightedness is gradually reduced. Since your vision will be changing, you'll need to wear disposable soft lenses during the day.
Once the treatment is over, you can wear the GP lenses at night only and see well during the day without any corrective lenses.
Some people need to wear their lenses only every other night, or even once or twice a week, to maintain the effect.
You will need to see your eye care professional regularly to ensure your lenses are fitting well and your eyes are healthy.
Since during sleep the lenses fit tightly on the eye, it's especially important to clean and disinfect the lenses upon removal each morning.