title: Patient responses to gas-permeable hard (Polycon) contact lenses.
abstract: Forty-six patients who were unable to wear polymethylmethacrylate (PMMA) contact lenses, owing mainly to corneal edema and associated symptoms, were fitted with gas-permeable hard Polycon lenses of the same dimensions. Thirty-one patients (67%) wore the POLYCON lenses successfully. Thirteen (28%) did not, because of discomfort. For 2 patients, the results were unknown. None of the 46 patients exhibited observable edema with the POLYCON lenses. For a group of 5 patients (10 eyes), mean corneal thickness change after 8 hr of lens wear was insignificant. Oxygen transmissibility of these lenses is approximately 5.0 X 10(-11) (cm2 X ml O2)/(sec X ml X mm Hg), a value less than that for hydrogel lenses which produce more edema. It is predicted that gas-permeable hard lenses will eventually replace PMMA lenses.
mesh_terms: D000293:Adolescent; D000328:Adult; D003258:Consumer Behavior; D003261:Contact Lenses / Q000009:adverse effects; D003315:Cornea / Q000033:anatomy & histology; D003316:Corneal Diseases / Q000209:etiology; D004487:Edema / Q000209:etiology; D005260:Female; D006801:Humans; D008297:Male; D008768:Methylmethacrylates / Q000009:adverse effects*; D008875:Middle Aged; D010100:Oxygen; D010539:Permeability; D012030:Refractive Errors / Q000534:rehabilitation*; D012828:Silicones / Q000009:adverse effects*
chemical_list: D008768:Methylmethacrylates; D012828:Silicones; C015464:polycon; D010100:Oxygen