A Chronology of Corneal Lenses

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

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.
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.
1979 – Menicon in Japan introduce the Menicon O2 silicone acrylate lens. This is later followed by Menicon SP and Menicon EX in 1986.
1980 – Polycon, an early silicone acrylate gas-permeable material, is introduced by Syntex. This is followed by the improved Polycon II in 1982.
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).
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).

A Chronology of Corneal Lenses

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.

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

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.

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.

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.

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).

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).

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.

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.

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

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

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).

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).