by Joel Harrison
15. November 2010 11:09
American patients who had problems finding silicone hydrogel lenses that would fit their eyes can buy lenses designed especially for them now.
Silicone hydrogel contact lenses, introduced in 2002, are in many respects superior to traditional hydrogel lenses, mainly because they have higher gas permeability. However, they were not available to all patients in need of vision correction due to the limited number of versions large contact lenses manufacturers offered.
Now, the situation has changed thanks to Contamac, a UK supplier of contact lens materials, which has received American Food and Drug Administration’s approval for a silicone hydrogel material that smaller manufacturers will be using for the production of custom contact lenses.
The material is called Definitive and is characterised by a three times higher oxygen permeability than conventional hydrogel materials, resulting in a lower risk of infections, red eye and other complications connected with contact lens use.
Definitive differs from other silicone hydrogel materials in that it designed to be lathe-cut to produce customised lenses. By contrast, large manufacturers usually use moulding processes, which reduce costs, but limit the number of available contact lens designs.
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