Gas permeable lenses are rigid, but made of materials that allow the eye to breathe. They are one way of correcting for significant amounts of astigmatism. They offer superior vision but are not as comfortable as soft lenses. Soft lenses offer comfort and good vision for most people. If a person has much astigmatism, they need either special soft lenses called toric lenses or gas permeable lenses.
Disposable lenses are the newest type of contact lens.
Many eye health problems that develop while wearing contacts are due to a buildup of deposits from your tears. With disposable contacts you don't keep the lenses long enough for that buildup to occur. Disposable lenses are also much more convenient because you always have a spare pair. It's not a problem if you lose or tear a lens. The lenses are removed and cleaned each night.