[Clinical and experimental evaluation of hydrophilic contact lenses for continuous-wear (author's transl)].

In a clinical and experimental study we tested a new contact lens for continuous-wear. The modified HEMA-lens ("Permalens", Global Vision Ltd, Southampton/GB; Cooper Laboratories, Düsseldorf) has a water content of 74% at pH 7.4. The oxygen transmissibility is, depending on the thickness of the lens, 38--67% of the oxygen in the air. In a first trial we had to eliminate 6 patients due to wrong fitting (much too steep) or dry eyes. After development of a new guide for selection of lens base curves 10 patients with monocular aphakia (10 eyes) and 12 patients with mild myopia (24 eyes) were fitted with the hydrophilic soft contact lens for permanent wear. From a total of 34 eyes in 11 cases (32%) the lenses were removed due to complications (1 conjunctivitis, 1 keratitis, 1 vascularization) or due to lack of cooperation. In 23 cases (68%) the continuous-war lenses were well tolerated without complications for 5 months. In a comparative study in vitro we tested the effect of the contact lens on the viability (swelling rate, intracellular membrane potential of the epithelium) of the isolated human cornea. A damaging effect of the lens on corneal function was not observed. The hydrophilic soft contact lens can be fitted for continuous-wear.