Soft contact lenses are made of soft, flexible plastics that allow oxygen to pass through to the cornea. Soft contact lenses may be easier to adjust to and
are more comfortable than rigid gas permeable lenses. Newer soft lens materials include silicone-hydrogels to provide more oxygen to your eye while you
wear your lenses.
Soft Lenses are, as the name suggests, a soft plastic gel material called a hydrogel. They become soft due to the hydrophilic or "water-loving" property of
the plastics used. The first materials were just 38% water content, but were still revolutionary in their day because they were much more comfortable than
other lenses available at the time.
Oxygen is transported through the material in the water within the material.
As materials developed, more water was included in the lenses and at one stage 85% water content materials were being produced. However these were simply too fragile, so these higher water content lenses had to be made thicker in order to make them durable. This meant that the oxygen had further to travel and resulted in no extra benefit in terms of oxygen transmission. Also these high water content lenses were difficult to keep clean and so in time the industry settled upon 50-60% water content as being the optimum for the majority of uses. Some 38% lenses are still used, as are some 70% materials in special cases.
The 50-60% ceiling on water content effectively limited the maximum amount of oxygen that a soft lens could transmit. Soft lenses are very comfortable and so patients can be misled into thinking that their lenses were doing no harm, yet the cornea underneath the lens was being starved of oxygen. This has been the major problem with soft lens wear over the years, with practitioners constantly warning against overwear, and patients ignoring the warnings because of the intrinsic comfort of the lenses.
This led to the search for materials that could transmit the necessary levels of oxygen to sustain the cornea during the longer periods of wear that patients were demanding.
Rigid gas permeable contact lenses (RGPs) are more durable and resistant to deposit buildup, and generally give a clearer, crisper vision. They tend to be less expensive over the life of the lens since they last longer than soft contact lenses. They are easier to handle and less likely to tear. However, they are not as comfortable initially as soft contacts and it may take a few weeks to get used to wearing RGPs, compared to several days for soft contacts.
contact lens materials are uniquely manufactured, using highly purified monomers to provide the finest materials, which ensure your finished contact lenses result in the ultimate "on eye" wearing experience.
GM Advance is the latest in soft lens material innovation; Building on the chemistry of the GM3, this material has been developed to provide the ultimate on eye wearing experience. Utilizing the highest purity monomers, a careful blend results in a material that exhibits exceptional on eye stability, water retention and durability. This exceptional combination of properties ensures that manufacturers yields are high and lens returns remain low, due to high patient satisfaction and low levels of lens breakage.