How many types of contact lenses?

[Ponder]

How many types of contact lenses?

[McRae]

If you opt for contact lenses, you have several varieties to choose from, such as soft contact lenses,gas permeable contact lenses,hybrid contact lenses,daily or extended wear,contact lenses with sun protection,tinted lenses,specialty contacts.

[McRoberts]

Contact lenses can be divided into
several classifications:

By material characteristics: soft (cellophane-like) or rigid (formed flexible plastic).
By wear schedule: Daily Wear or Overnight Wear (also called "Extended Wear", a
modality which has fallen into disfavor because of the high incidence of
complications).
By life-span of the lens: Disposable (1 day or 2 week), Planned Replacement (1
month, 3 month or 6 month), or Conventional year or 2 year).
By correction modality: Spherical, Toric or Astigmatic, or Bifocal

[Minturn]

As I know that there are 5 types of contact lenses. Rigid gas-permeable (RGP), made of slightly flexible plastics that allow oxygen to pass through to the eyes. Daily-wear soft lenses, made of soft, flexible plastic that allows oxygen to pass through to the eyes. Extended-wear available for overnight wear in soft or RGP lenses.Extended-wear disposable soft lenses worn for an extended period of time, from one to six days and then discarded.Planned replacement soft daily wear lenses that are replaced on a planned schedule, most often either every two weeks, monthly or quarterly.