Contact Lens Designs
There are various lens designs to correct different types of vision problems-
Spherical contact lenses
are the usual, rounded design of contact lenses. They are used to correct myopia (nearsightedness) or hyperopia (farsightedness).
Bifocal contact lenses
are lenses with two sections. They are made for near and far vision to correct presbyopia.Bifocal contact lenses are available in both soft and rigid gas permeable (GP) materials. There are disposable lenses available too, which can be used only for a day or for short intervals and then discarded. Also, one bifocal brand is available in silicone hydrogel material.
Orthokeratology lenses
are specially designed to reshape the cornea during sleep, providing lens-free daytime wear.
Toric contact lenses
are worn to correct astigmatism, as well as myopia and hyperopia. Toric contact lenses are made from the same materials as regular "spherical" contact lenses, so they can be either soft or RGP. The difference lies in the design of the lens.
Toric lenses carry two powers, created with curvatures at different angles, one for astigmatism and the other for either myopia or hyperopia. There's also a device to keep the contact lens stable on the eye when you blink or look around.
All of these lenses can be made to order. There are other lens designs available too. These are less common and made to correct problems such as keratoconus.