Embedded Files
Page 5
But in the late 1940s, it marked a designs for bifocal and trifocal scleral contact lenses in major shift from mid-1930s. scleral to corneal Poly (methyl 2-methylpropenoate) But Dr. Feinbloom’s key contribution to the field of contact lenses. PMMA lenses was recognizing the many advantages of Prior to this, substituting plastic for glass in the eye. In 1936, he many fine introduced and patented the first contact lens containing optometrists, plastic. This lens had a central glass optic that covered ophthalmologists, the cornea with an opaque plastic flange over the sclera. and scientists— At the time, glass contact lenses were the standard, but including Theodore had never been very successful. Glass was transparent, Obrig, Philip but it had a number of disadvantages, including weight Salvatori, Ernest and complete lack of oxygen permeability that rapidly Mullen, Itsvan led to discomfort and corneal hypoxia for the wearer. Gyorrfy, Solon Braff, The lenses were also difficult to make. and Edward Goodlaw— With plastic, the lens weight could be reduced, the had been designing and producing all-PMMA lenses in material could be formed and shaped easily, it had good scleral designs. PMMA was introduced in the U.S. by compatibility with ocular tissue, and was more Rohm and Haas Company in 1936, and many comfortable in the eye than glass. laboratories began making plastic contact lenses on a Initially, Dr. Feinbloom used the only plastic available limited scale shortly thereafter. These lenses were a vast to him—an opaque resin plastic that would not have improvement on earlier glass lenses, especially with been effective for the optical portion of the lens. But fitting modifications and new design elements such as his ideas were prescient. PMMA, which has superb fenestration; but they continued to suffer from the optical properties, was introduced in the U.S. that same problem that all scleral lenses trapped tears between the year and rapidly became the material of choice for hard lens and cornea, resulting in corneal hypoxia. lenses. Because of this, scleral contact lens fitting remained a Many remember William Feinbloom as a tireless very limited procedure undertaken by relatively few advocate. “My father was generous with his time and his people around the world. But after the introduction of knowledge,” recalls son Richard Feinbloom. “And he was the Tuohy corneal lens, contact lens sales increased from passionate about helping people with low vision.” 50,000 pairs in 1946 to 200,000 pairs in 1949.2 The primary advantage offered by this revolutionary [ KEVIN M. TUOHY (1921-1968) ] combination of lightweight plastic and a corneal design In 1948, A California optician who worked for Solex was the potential for increased tear exchange behind the Laboratories, Kevin Tuohy, filed a patent for the first lens,” Mertz says of the Tuohy lens.3 Patient comfort was corneal contact lens, which was made entirely of PMMA. still a limiting factor, but Mr. Tuohy’s innovation enjoyed His discovery began—as so many do—with a laboratory great success by the standards of the day. mistake.
Google Sites
Report abuse