Soft contact lenses are made from a flexible plastic material that absorbs water and therefore moulds smoothly to the shape of your cornea. The two main material groups are hydrogel and silicone hydrogel. Hydrogel lenses consist mainly of water and are soft and comfortable, whilst silicone hydrogel lenses also contain silicone, which allows more oxygen to reach your cornea.
The water content of soft lenses is usually between 38 and 78 per cent. A higher water content makes the lens softer and often more comfortable to insert, but can also mean that the lens draws moisture from your eye more quickly. Silicone hydrogel lenses combine a lower water content with high oxygen permeability, making them suitable for longer wearing times and for people with dry eyes.
Soft contact lenses are available in various wear schedules: daily disposable lenses that you discard after one day, fortnightly lenses, monthly lenses and, in some cases, lenses for longer periods. There are also soft lenses for various vision corrections, such as spherical lenses for short-sightedness or long-sightedness, toric lenses for astigmatism and multifocal lenses for presbyopia.
As the material is flexible, soft lenses stay securely in place, even when moving around or playing sport. They are larger than hard lenses and cover the entire cornea and a small part of the surrounding white of the eye, which contributes to their comfort.