There are a wide range of contact lenses available on the market nowadays. In order to have the most suitable one for our eye need, we must have some understanding of these contact lenses and know their differences. The following will give some introduction on the different categories of contact lenses in the hope of giving people more help in choosing the best lens for themselves.
The main common type of contact lenses are hard and soft lenses. Both hard and soft lenses are made of various types of polymers, which usually contain some different kinds of hydro gel. At the beginning, hard contact lens was made out of a polymer, called PMMA, but it can not allow oxygen to get through it to the eyeball, so people would feel uncomfortable or irritated to wear them. Then rigid gas-permeable contact lens is introduced, shorted for RGP. Nowadays, RGP and soft contact lenses are made of hydrophilic material which is a kind of water-absorbing material and can allow more oxygen to get through it and reach our cornea. Therefore, the lenses are comfortable to wear.
As the hard lens is replaced by rigid gas permeable lens, so the main types of contact lenses are soft lens and rigid gas permeable lens. Both of them have their own advantages. For soft contact lens, it is easier and more comfortable to wear as it is moveable and can allow more oxygen to reach our cornea. And RGP lens enables people to have a clearer vision as the lens is sturdier. Besides, RGP lens are more durable and can be worn for longer life expectancy. Both rigid gas permeable and soft lenses can come into disposable lens, and soft lens is more popular for disposable lens, which can be worn from seven to thirty days based on its specific use and features.
Besides disposable contact lenses, for people who need to wear the lens for almost all the time, they can choose extended contact lens. Most of extended contact lenses are soft contact lenses, while just a few are rigid gas permeable lens. The extended contact lens can be worn for the specific requirement of time without removing them, and till its valid date, we can just discard them.
Another type of contact lens is the specialized contact lens called Ortho-K. With the help of Ortho-K, we can change the curve in our cornea temporarily, but it is not a permanent fix. This will be good for preventing our eyes from still and keeping the curvature of our cornea.
For contact lens wearers, there are some cleaning and maintenance tips we should follow. In case that we lose one lens, or our eyes get infected, it is better to bring a pair of glasses with us. And before handling the lens, it is a must to wash our hands.