For any given substance, the heat capacity of a body is directly proportional to the amount of substance it contains (measured in terms of mass or moles or volume). Doubling the amount of substance in a body doubles its heat capacity, etc.
Conventional soft contacts can last up to a year; conventional rigid gas permeable (RGP) contact lenses can last even longer. Frequent or planned replacement contact lenses last one to several months. Disposable contacts last from one day (daily wear) to up to two weeks (extended wear).
This is typically one to two years from the date that the contact lenses were fitted. BC values range from about 8.0 to 10.0. The doctor fits the lens with the curvature most appropriate for your eye. Most lenses come in several different BC values.If your prescription does not contain a BC value, this is likely because your brand of lens only comes in one base curve. BC values are a bit like clothes sizes-just because you are a BC 8.6 in one brand doesn't mean you will be the same in another brand.n addition to the lens power, your contact lens prescription contains several other pieces of information related to the size of the lens. Even the power of the lenses is generally not the same as in your eyeglass prescription.