David Volk
(1918-1987) of Pepper Pike,
Cleveland, Ohio
graduated in optometry in 1939 from
Ohio
State
University, returning to graduate with a medical degree in 1946.He was granted several
US
patents in 1965 and 1966 describing methods and machinery for generating
aspheric surfaces.Volk met with Gene Hirst in
New Zealand
in 1964.Hirst
had already produced the V contour lens to approximate to the curvature of the
cornea.This
design had a multicurve construction which with blending had about seven back
curves in all.Hirst produced Con-o-Coid lenses in 1966 in collaboration with Volk.He had exclusive rights to Volk patents anywhere in the world other than
the
USA
and
Canada
which had been granted to Obrig.
Volk
was granted several more
US
patents in 1967 concerning the generation of aspheric surfaces on contact
lenses.These led, in 1968, to the
launch of an improved Con-o-Coid lens by Obrig, in collaboration with Volk and
using entirely new equipment.Volk's
US Patent 3,482,906 of 1969 detailed a projected range of mass-produced corneal
lenses with concave ellipsoid surfaces.These
had base curves between 6.50mm to 8.50mm with 0.05mm intervals and
eccentricities from 0.4 to 1.6 at intervals of 0.1.The patent also covered the possibility of a conicoidal front surface to
reduce thickness.
