Rigid Gas Permeable Contact Lenses are individually designed and made for you and have the widest possible range of prescriptions, fittings and materials. The quality of vision is often superior to soft contact lenses. Also, since they are smaller and less delicate than soft lenses, they are often easier to handle, insert and remove. Basic lenses will correct low amounts of astigmatism, but there is also a full range of toric lenses available and bifocal / multifocal lenses can be fitted for those who need extra help with close work. With lenses lasting up to two years and a simple care regime, they can be the least expensive option. Rigid Gas Permeable lenses are often as comfortable as soft, but the build-up to all-day wear takes longer (up to four weeks). They are generally unsuitable for intermittent wear and should be worn most days to maintain tolerance. Eye colour changing is not possible.