AO Lens Design training tools
-
the Donut and Football model
in Don Whitney's Gay Travel Bag -
by Dick Whitney
My father Don Whitney joined American Optical
in 1947 and began work in the Lens Design department here in Southbridge,
MA.
He was hired by John
Davis and had the good fortune to also work under the leadership of
both Dr. Tillyer and Dr. Glancy.
These three were giants in the industry, and he was fortunate to have
such experts to learn from.
This recollection deals with these training tools and the bag frpm
the 1960s that still contains them.
One aspect of understanding ophthalmic lens design is learning the fundamentals
of the toric surface of a lens - used to correct for astigmatism in the
eye.
The toric provides provide correction for astigmatism, for by placing
a such a surface on either the front or the back of the lens,
the powers will differ depending upon the angle one looks away from
the center of the lens.
It so happens that the two most commonly used toric are actually sections
of either a donut or football.
The models above which I donated to the Optical Heritage Museum, were
used by Dad when he trained others on this concept;
he was trained with these models when he joined the AO Lens Design
group in the late 1940s.
Shown below are two view of the curves on a donut surface. The one on
the left show a 6 Diopter curve brass tool, and if one slides this around
the donut
in the direction it is pointed the curve stays constanct. If however,
the donut is rotate 90 degress, it will be a 6 curve only near the very
center but steepens as one moves away from the center.
Additionally, in this direction the curve changes as one moves away
from center and is therefore aspheric.
The donut toric is further described in the 1947 training manual except
below these photos.
The football example (below) has its 6 Diopter curvature along the length
of this model.
Again if one turns the model 90 degress, this curve is also steeper
than the 6 curve but in that cross section it is also uniform in curve
and therefore different from the donut.
1947
AO Branch Managers Training Manual Excerpt explaining the donut toric geometry
5mb pdf download
When Don left Lens Design, he worked gravitated toward manufacturing where he started the AOLITE plastic lens deptartment and also became involve in ANSI and ISO Standards as I am today. Periodically he gave training sessions and at times traveled with these models and used them in presentations. A local travel agency at the time (1960s) was called Gay Travel - in subsequent years it changed names to Sturbridge travel and it is a bag from this agency where Dad stored these training tools.
When Dad began working closely with another industry great (Dave LaMarre) and taught him ophthalmic lens optics, this model became a symbol of honor which he passed on to Dave. In the late 1980s, Dave, Don (now as a consultant for AO) and I worked on Apheric Lens design. When Dave left AO to join Gentex, he handed this bag to me which I have treasured since that time. It now has just been donated to the Optical Heritage Museum where I hope this legacy will be appreciated.
