Ortho-K lenses work by temporarily moving fluid in the central corneal epithelium out to the peripheral cornea, effectively flattening the cornea for a period of time. To accomplish this, the patient wears a custom lens to sleep each night, at first to reshape the cornea, and then long-term to maintain the reshaping. This concept of flattening the cornea is the same that is utilized in LASIK, but LASIK actually removes part of the cornea, which is non-reversible. After going a week or more without wearing Ortho-K contact lenses, the cornea will return to its original shape.
The majority of the corneal reshaping process takes place within the first several weeks of wearing the contact lenses. Patients will often notice improvement in their unaided vision within a couple of days. Because of these rapid changes, new wearers will require a series of office visits during the first month of wear. Once the appropriate lenses are fit, follow-ups are reduced, and long-term wearers simply need to be seen every 6-12 months.
In addition to removing the need for daytime contacts and glasses, orthokeratology may help to slow the progression of myopia (nearsightedness) in children. Many factors contribute to worsening myopia, and often the largest changes in vision take place during childhood and adolescence. While each child is different, a number of studies over the past fifteen years have supported the credence that Ortho-K contact lenses have the potential to slow down these rapid changes.