A. Leonardo Da Vinci - first person to neutralize the cornea by substituting for it a
new refracting surface. About 1508, he described several forms of contact lenses that
would accomplish this purpose.
B. Rene Descartes - the first individual to suggest placing a lensdirectly upon the cornea with scleral contact (about 1636 or 1637).He demonstrated the cornea's role in astigmatism by use of a hydrodiascope-like device.
II. BLOWN GLASS - FLUID
A. F.A. Muller (1887) - Weisbaden glassblower made first scleral nonoptical lens.
B. A. Eugen Fick (1888) - Zurich physician - made first refractive-powered contact lens. These 18-21mm diameter lenses were designed to correct traumatized and/or irregularly shaped corneas. These were blown glass and were heavy and difficult to make.
C. August Muller (1889) - made lenses to correct his myopia. He molded human eyes and made bicurve and tricurve designs. He was also the first to explain lacrimal exchange.
III. FLUIDLESS GLASS SCLERAL
A. Josef Dallas (Budapest) - fluidless glass scleral lenses, 22x25mm using eye molds. Ground corneal section optics were also present. The benefits of the eye mold included a more secure, controllable and comfortable fit. Fenestrations minimized adhesion and enhanced lacrimal exchange (1930-34).
B. Adolf Mueller-Welt (Stuttgart, Germany) - produced fluidless glass scleral lenses, beginning in 1927. He designed lenses to allow lacrimal fluid to circulate between lens and cornea. He was first to develop large trial sets/inventories and, with Joe Breger, initiated one of the first large CL laboratories in the U.S.
IV. SCLERAL PMMA (Polymethylmethacrylate)
A. PMMA served as the primary contact lens material from the late 1930's to the late 1970's due to:
1. Lower specific gravity
2. Better & faster reproducibility
4. Could be fenestrated
5. Difficult to break
B. William Feinbloom (1937) - combined glass corneal section with a plastic scleral section contact lens.
C. First All PMMA Lenses (1938-40) - via numerous manufacturers.
V. CORNEAL PMMA
A. Kevin Tuohy - California optician who's large (11.5-12.5mm), flat (2.5-6 diopters flatter than "k"), thick with blunt edges revolutionized the contact lens field. This was the first corneal PMMA contact lens design. Patent applied for in 1948; granted in 1950.
B. Butterfield (1950) modified Tuohy design for alignment fit.
C. Design Changes - change from large, flat designs to small, steep (apical clearance) designs. For example, in 1960 Bayshore introduced a small diameter (7.0-8.6mm) steep design with a central fenestration to reduce edema.
Fenestrations - beginning in late 1950's - were often used to reduce edema (typically either 3 small central or 20 larger peripheral holes were used). Problems included tears clogging up the holes, and flare.
D. Major Laboratories
1. Obrig (New York)
2. Breger-Mueller-Welt (Chicago)
3. Plastic CL Company (Wesley-Jessen, Chicago)
E. Modified PMMA Designs (late 1950's)
1. Vent Air - semicircular grooves in the posterior surface.
2. Spiro Vent - "jet propulsion" posterior grooves designed to ensure rotation and tear flow.
3. Stimson keraform lens - 4 projections to minimize rotation.
A. Hydrogel Development
1. In 1963 and 1964, Dr. Otto Wichterle, polymer chemist at the Czechoslovak Academy of Sciences developed a hydrophilic plastic compound (hydroxyethylmethacrylate (HEMA)
2. A child's erector set was used to develop a spin-casting technique for shaping HEMA into contact lenses.
1. First American to have access to Dr. Wichterle.
2. Obtained some of Wichterle's samples and technical information.
3. Bypassed opportunity for further involvement.
C. National Patent Development Corporation
1. Martin M. Pollak visited Dr. Wichterle in Prague (1964).
2. Applications were discussed and Dr. Morrison was selected to assist.
3. NPDC established Flexible Contact Lens Company.
4. October, 1966 B&L signed a licensing agreement with NPDC.
5. FDA classified soft lens as a drug; therefore delaying product launch from 1968 to 1971.
D. Robert Morrison
1. French O.D. Rochet told him of Wichterle. He then visited Prague 10 times and brought back materials becoming first American to fit these lenses in practice.
2. Czechs almost signed over all of the patents until Pollak called.
3. Gave up 50% control of Flexible Contact Lens Co. and settled out of court.
E. Alan Isen
1. Reported on hydrogels at 1964 American Academy of Optometry meeting.
2. Became head of NPDC's soft lens division (instead of Morrison)
VII. RIGID GAS PERMEABLE
A. 1970's - "Modified" PMMA - Did not transmit oxygen.
B. Cellulose Acetate Butyrate - 1978 became first approved RGP; very low oxygen permeability and unstable.
C. Silicone/Acrylate (Polycon I) - January 1979. Gaylord patent of 1974 paved the way. Syntex bought the material from Leonard Seidner in 1977.
A. Becker (1956) developed silicone elastomer.
B. Advantages (oxygen stability and flexibility).
Disadvantages (wettability, adherence)
C. Breger worked on it from 1959-72.
D. Dow Corning made silicone elastomer and hard silicone resin before selling in 1984.