A contact lens is a thin disk which floats on the surface of the eye, providing vision correction.With advances in optical technology, almost everyone now can wear contact lenses, regardless of the type or extent of their vision problems. This includes patients with astigmatism and those who need bifocal or multifocal lenses. There are two classifications of contact lenses -soft and rigid gas permeable lenses. All contact lenses require a prescription.
Soft Contact Lenses
Daily-wear soft contact lenses are by far the most popular type of contacts worn. Made of a flexible plastic polymer, daily-wear lenses are put in each morning and taken out each night. They are replaced according to an established schedule.
Extended-wear soft contact lenses can be worn all the time, including while you sleep. Depending on whether you have 7-day (standard) or 30-day lenses, you only need to take out and clean your contacts once a week to give the eyes a rest and reduce the risk of a corneal infection. Extended-wear lenses are made of soft silicone that retains moisture longer than daily-wear contacts, allows more oxygen to reach the eye, and prevents bacteria and protein buildup.
Although many patients prefer the convenience of 30-day contacts, be aware that they tend to be stiffer than 7-day lenses, scratch more easily and may be blurrier.
Disposable soft lenses are intended to be thrown out and replaced after you've worn them for a certain length of time. This makes them even easier to maintain than regular soft contacts. Many disposable lenses are designed for replacement each morning, every two weeks, or even every months. Daily-wear disposables are worn during waking hours only, while extended-wear disposables can be worn for longer periods.