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With modern RGP materials, we’re able to meet corneal oxygen needs as well as provide effective near and distance correction,” he said.Also in the 1980s, the first hybrid technology lenses were introduced, beginning with the Saturn lens. The next iteration, the Softperm lens, had a rigid, low-Dk center with a low-water content soft lens surround. Typically worn by hard-to-fit keratoconus patients, it has been plagued by insufficient oxygen transmission as well as tears at the junction of the two materials. Recently the SynergEyes “A” and “KC” lens designs, with a hyper-DkGP center, hold promise for the successful management | 15 of patients who could not wear GP lenses otherwise.Another major contributor to the rigid lens correction of keratoconus is Joseph Soper, who designed a number1981The Permalens becomes the first extended-wear lens approved by the U.S. Food and Drug Administration, with a 30-day extended wear indication.of lenses, including one that bears his name: the Soper Cone. Leonard Bronstein, O.D., also deserves credit as an innovative pioneer in PMMA and GP design, especially in the areas of bifocals and irregular corneas. The symposium that still bears his name is one of the most successful contact lens programs in the world, with the 33rd annual meeting held in January 2007.Hydrogel LensesAs soft lenses got better, safer and more comfortable, patients and clinicians naturally started to think about longer wearing periods. First in Europe and later in the United States, contact lens wearers became increasinglyinterested in semi-permanent vision-correction lenses they could sleep in and wear continuously for long periods of time.London optometristJohn de Carle, O.D., thought increasing the water content of hydrogel lenses from the low levelsJohn de Carle, O.D. (38%) in the early HEMAlenses to approximately 75% would permit such extended wear, especially if the lenses were slightly smaller in diameter than those in use at the time, which were about 14.5mm.After obtaining a list of suitable plastics from the library, Dr. de Carle carried out experiments in the kitchen of his London flat. He once had to apologize to the neighbors for the odors issuing from his oven when one of the jam pots of plastic he was cooking exploded. He finally created a satisfactory high-water content (72%) polymer, perfilcon A, and used it to make a new lens, which he dubbed the Permalens. He made it12.50mm in diameter. “To keep a very soft lens of that size in place, it was often necessary to make the inner radius steeper than the cornea,” Dr. de Carle explained.
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