Hard Contact Lens

Hard Contact Lenses Have Its Own Advantages

Several types of contact lenses are available to take care of your eyes including hard contact lenses. There are two types of hard contact lense. The first one is the conventional hard (polymethyl methacrylate, or PMMA) lenses that are made of a fairly stiff plastic. Though they correct vision with no distortion, they are the least comfortable type of contact lens. The second one is the rigid gas-permeable (RGP) lenses that are more comfortable than conventional hard lenses. In fact, some gas-permeable lenses are designed to be worn overnight and for up to 7 days.

Though hard contact lenses provide clear vision and last for a fairly long time (5 to 10 years), there are only a small number of hard contact lens wearers. In fact, the inconvenience that the non-gas permeable lenses do not allow oxygen to reach the cornea can have bad repercussions which can lead to major eye damage. Before 1971, every contact lens was made of PMMA. The advent of gas permeable lenses brought a reprieve from the PMMA lenses as it allows oxygen to pass through it to the cornea, resulting in greater comfort.

Rigid gas permeable lenses are more rigid than soft contact lenses and therefore are more durable. The new type of rigid gas permeable lenses are made with silicone polymers, allowing oxygen to circulate to the cornea of the eye. They can be disposable contact lenses, bifocal contact lenses, colored contact lenses, cosmetic contact lenses etc. One great advantage of rigid gas permeable lenses is that unlike soft contact lenses, these lenses maintain their shape and offer clearer vision for some types of corrections. You can easily take care of these lenses which are extremely durable. You only need a good contact lens cleaner for cleaning these contact lens. The amount of time needed to adjust to rigid gas permeable contact lenses is longer than the soft contact lenses. To achieve maximum comfort, a rigid gas permeable contact lens should be worn every day. There are some rigid gas permeable contact lens problems.

Rigid gas permeable contact lenses are also available in extended wear options, meaning you can wear them overnight. Sleeping in extended wear contacts may decrease the flow of oxygen to the cornea, so it is important to wear them as directed. As oxygen is not passed, you can have contact lenses dry eyes. Rigid gas permeable lenses also provide better deposit resistance than soft contact lenses. But, because soft lenses are instantly comfortable to wear, they are more preferred than the gas permeable lenses. Gas permeable lenses require an adaptation period before they become comfortable. Also, some people experience "spectacle blur" with gas permeable lenses. When gas permeable lenses are removed, vision is blurry, even while wearing glasses. This effect is temporary, but it can necessitate full-time gas permeable wear. This can make gas permeable an all-or-nothing proposition, which some people will find inconvenient.