The eventual comfort of gas-permeable lenses lies somewhere between that of soft and hard lenses. Novice contact lens wearers will experience some of the initial foreign-body sensation similar to that of the hard lens, but the point at which they can be worn full time comes much sooner. In addition the number of hours meant by “full time” is longer: sixteen hours is common, as opposed to the eight that’s usual for conventional hard lenses. Some who switch from conventional hard lenses to gas-permeable lenses are not initially impressed with the difference in comfort and wearing time, but this gradually improves as the eye recovers from the effects of wearing (and overwearing) their original hard lenses. Read the rest of this entry »
According to the present laws, the FDA classifies as a “drug” any contact lens that contains material other than the PMMA from which standard hard lenses are made. This includes, of course, all soft contact lenses; and since gas-permeable lenses contain either silicone or CAB, they fall into this category as well. The FDA feels that all the lenses in this class should be sterilized. Thus by FDA decree the manufacturers of gas- permeable lenses must recommend that you use the same regimen and solutions for cleaning, rinsing, and chemically disinfecting as with soft contact lenses. (Boiling, or heat disinfection, is not recommended, as the lenses would be ruined.) The literature that accompanies the lenses even warns, in large print, that unless you clean and disinfect the lenses daily, you may develop a “severe” ocular infection. However, I have not found this to be the case. In fact I have found that the solutions recommended by the FDA do not adequately clean the gas-permeable lenses and they may even produce some allergic reactions. Nor do they contain any wetting agents to make the lenses more comfortable on the eyes. And, as representatives from the gas-permeable lens manufacturers note, the hard-lens cleaners perform better in ridding some of the lenses of mucus buildup. Read the rest of this entry »
Contact Lenses Care .
