CONTACT LENS HISTORY

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A CHRONOLOGY OF CORNEAL LENSES

[ A Glossary of technical terms ]

1947 Kevin Tuohy first applies for a patent for a corneal diameter lens.  This is fitted flatter than the cornea, has a constant overall diameter of 11.50 mm, a flange (or peripheral ) width of 1.5 mm and a central thickness of 0.25-0.35 mm.

Tuohy corneal hard lens design.

1947 Heinrich Wohlk between 1946 and 1948, independent of Tuohy, develops a corneal diameter lens fitted flatter than the corneal curvature.

Wohlk Contact Lenses (Linsen) - early hard lens design.

1952 The Microlens is launched in England by Frank Dickinson; in Germany by Sohnges; and in the USA by Jack Neill.  The single curve design is fitted flatter than the cornea, has a constant diameter of 9.50 mm and a thickness of 0.20 mm for an afocal lens.

1957 Norman Bier introduces the Contour lens which consists of a relatively small optic zone surrounded by a wide peripheral curve between 0.40 and 0.70 mm flatter than the central radius.  It is fitted in corneal alignment with a standard diameter of 9.65 mm.  (Tear lens diagrams from The Contact Lens Manual, Andrew Gasson and Judith Morris, 2003).

Contour hard lens tear lens diagrams.

1964 Freddie Burnett Hodd designs the Hodd Tapered Lens which has a series of carefully calculated peripheral curves.  Fitting sets are available through Nissel.

1966 Corneal lenses with offset peripheries are designed by Montague Ruben, head of the Contact Lens department at Moorfields, and manufactured by Omega Contact Lenses.

Omega parabolic offset fitting set.

1967 Nissel introduces an aspheric design based on the work of Volk in the USA.  It consists of a central aspheric portion with a 7.80 mm diameter, two spherical zones at diameters of 8.40 mm and 8.80 mm, and a flat edge bevel to assist tear flow.

Early Nissel price list.

1967 Penrhyn Thomas in Australia introduces the Conoid lens which consists of a steep central optic with tangential peripheral curve.  (Illustration from "Conoid Contact Lenses, Penrhyn Thomas, 1967).

Conoid hard lens design.

1966 Janet Stone designs a series of lenses with Constant Axial Edge Lift.  These are multicurves which for a given overall diameter have the same edge lift throughout the range of radii.  (Tear lens diagrams from The Contact Lens Manual, Andrew Gasson and Judith Morris, 2003).

Constant Axial Edge Lift hard lenses.

HARD GAS-PERMEABLE LENSES
1975 The original Boston lens material is developed.  Following further research and development, it gains FDA approval as Boston II in 1982.

Boston lens logo.

1977 Cellulose acetate butyrate (CAB) is introduced as an early hard gas-permeable material for corneal lenses.  Compression moulded lenses such as Hartflex or the later Conflex from Wohlk, or Persecon from Titmus-Eurocon give dimensional stability.

Confelx and Hartflex.

1979 Menicon in Japan introduce the Menicon O2 silicone acrylate lens.  This is later followed by Menicon SP and Menicon EX in 1986.

Menicon 02, EX and SP

1980 Polycon, an early silicone acrylate gas-permeable material, is introduced by Syntex.  This is followed by the improved Polycon II in 1982.

Polycon

1980 Irving Fatt devises his Dk system for the measurement of oxygen permeability using a polaragraphic cell.  (Illustration courtesy the Contact Lens Collection of the College of Optometrists).

Polaragraphic cell used by Irving Fatt for oxygen measurements.

1987 The Diffrax bifocal is introduced by Pilkington in either Polycon II or Fluorocon 60.  The lens is based on the principle of a central area of diffraction providing near and distance retinal images.  (Illustration courtesy the Contact Lens Collection of the College of Optometrists).

Diffrax diffractive bifocal fitting set.

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