Contact lenses are available in many different styles. Generally when choosing contacts, you are first confronted with the choice of whether you want to wear hard contacts or soft contacts:
The majority of contact lenses made today are soft contacts. These are flexible and allow oxygen to pass through to the eye. Soft contact lenses are disposable and can be thrown away after a short period of use. Being able to have a fresh pair of soft contact lenses means less chance of infection, less cleaning, and more comfortable than rigid gas permeable contact lenses when first inserted into the eye. Water allows oxygen to pass through the contact lens material. Soft contact lenses are more comfortable to wear, especially for people whose eyes are susceptible to irritation from foreign objects, and also provide UV protection which is beneficial, particularly fot those with eyes that are more sensitive to sunlight.
Many soft contact lenses are made of soft polymer-plastic material combined with a percentage of water. While most people choose soft contact lenses because of their many benefits, they unfortunately also have some distinct disadvantages. Because of their water-based materials, soft contact lenses collect pollutants which can harm your eyes. Soft contact lenses are also more fragile than hard contact lenses and can rip or tear easily.
Soft contact lenses are made to be disposable and must be replaced from time to time. There are however some variables as some contacts are useable for a longer period of time than others. Generally, soft contact lenses come in two different types: Daily wear and extended wear.
Hard contact lenses are not as popular as they once were, but they are still an available option. The hard contacts of today have improved dramatically from what was available in the past thanks to new technologies and should not be confused with old style of hard contact lenses which were made with very rigid materials that didn't allow oxygen to pass through the lenses. Prior to the late 70's, hard contacts were made with a material called PMMA, which was non-permeable. Hard contacts today, however, are much more flexible and healthy, as they allow oxygen to pass through them - these are generally referred to as GP (GP stands for gas permeable), RGP (rigid gas permeable)lenses , or "oxygen permeable lenses".
GPs can be less expensive in the long term than soft lenses. They are generally more resistant than soft contact lenses. They can also be easier to clean, and since they're long-lasting, they are comparable to GPs in oxygen transmission). Most GPs incorporate silicone, which makes them transfer more oxygen to the eye than traditional soft contact lenses (although some silicone hydrogel soft lenses are actually a newer technology than soft lenses), which results in greater comfort and better eye health. GP lenses were first introduced in the late 1970s; they can also provide better vision, durability, and because silicone is oxygen permeable, oxygen can pass through GP lenses, resulting in GPs being better for the eye than PMMA.
GPs are extremely durable and offer some outstanding benefits over soft lenses. While they are still breakable, they are much less susceptible to tearing than soft contacts. Because RGP lenses are produced with firm materials, it keeps its shape much better than soft contacts do, and won't move around your eye much when you blink. And since the materials used to make them aren't water-based, things like protein from your tears won't build up on them. With a little care, they may last when you don't require a prescription change. Colored contact lenses can come with or without any eyesight correction. There are many different brands of lenses which come in all sorts of styles for people who want to change their eye color. Daily disposable, weekly disposable and monthly disposable color contacts are all available on the market.
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