Eyes prefer plasma-coated contacts.Eyes prefer plasma-coated contacts More comfortable contact lenses contact lenses contact npl → verres mpl de contact contact lenses contact npl → Kontaktlinsen pl contact lenses npl and more biocompatiblesurgical implants are just two of the envisioned applications for a new plasma-polymerization treatment developed at the University of Missouri's Materials Research Center in Rolla. According to according to prep. 1. As stated or indicated by; on the authority of: according to historians. 2. In keeping with: according to instructions. 3. Hirotsugu Yasuda, a developer of the process, not only does an ultrathin ul·tra·thin adj. Very thin. (30-nanometer-thick) coating of methane-plasma polymer make "hard' contact lenses more durable, scratch resistant and comfortable, but such coatings could also rescue prospects for silicone rubber Noun 1. silicone rubber - made from silicone elastomers; retains flexibility resilience and tensile strength over a wide temperature range synthetic rubber, rubber - any of various synthetic elastic materials whose properties resemble natural rubber as a preferred material for extended-wear lenses. And his preliminary animal studies indicate that this coating, when applied to the polymeric materials used as replacement veins and arteries, reduces their tendency to spawn blood clots Blood Clots Definition A blood clot is a thickened mass in the blood formed by tiny substances called platelets. Clots form to stop bleeding, such as at the site of cut. . Yasuda's process involves ionizing methane gas in a 70| to100|C vacuum chamber. This generates a methane plasma and its polymer--a three-dimensional "network' of amorphous (noncrystalline) carbon containing hydrogen atoms--that coats out to form an ultrathin surface. In one test, five people were asked to temporarily surrendertheir "hard' contacts while Yasuda coated one lens in each pair. It wasn't long before these people began complaining to their eye doctor that one of their contacts was bothering them; invariably in·var·i·a·ble adj. Not changing or subject to change; constant. in·var  i·a·bil it turned out to be the untreated lens, the one they had previously worn without complaint. These limited data suggest, Yasuda says, that the coating will make any lens considerably more comfortable. But their big application may be for the extended-wearmarket. Here silicone rubber has shown promise, Yasuda notes, because it has better oxygen permeability Oxygen permeability, abbreviated Dk, is a parameter of a contact lens. Another parameter, the transmissibility level, abbreviated DK/t; the Dk per thickness of the lens, is generally more used. Typical values are from 25 to 50. than any other polymer, good mechanical strength, excellent optical clarity and a physical softness the eyes appreciate. Unfortunately, he adds, it sticks to anything it touches and contributes to the eyes drying out. Yasuda found that by coating the surfaces of these lenses with the new methane plasma, he was able to eliminate both problems. |
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