Two Gems: Oblique Prism Calculation & Dr. Bessie Kehl


The DOC-L Listserve out of Southern College of Optometry, sometimes known as the VT-OD List, frequently offers up pearls of wisdom and two such gems were shared this week.  One is a handy dandy optical calculator that makes it easy to derive the resultant oblique prism power when horizontal and vertical prism are combined into one vector, shared by Linda Sanet.

Screen Shot 2017-08-31 at 6.02.26 PM

So take a guess at this before you scroll down:  If you wanted a net effect of 2^ BU in the R lens combined with 4^ BI in the R lens, what amount of prism would you order?  Drum roll …

Screen Shot 2017-08-31 at 6.15.47 PM

As you can see from the User Options menu above, there are alot of useful plug and play functions in this free online optical calculator.

The second gem is a Visual Training and Laboratory Manual (3rd edition, 1963) authored by Dr. Elizabeth E. (Bessie) Kehl from the Southern College of Optometry.  Dr. Walter Chao posted it as a Google Drive document, and Dr. Jean-Pierre Lagace re-posted deleted its blank pages in this dropbox link.  It is a wonderful historical compilation and although dated, still contains some very useful perspectives and information.  Dr. Glen (Bubba) Steele shared some nice reminisces of Dr. Kehl who was a mentor of his at SCO, a wonderful way of breathing life into her tombstone.

Bessie Kehl

2 thoughts on “Two Gems: Oblique Prism Calculation & Dr. Bessie Kehl

  1. Thanks for posting both. I used her manual for the VT lab taught by Harvey Brown and also our seminar was to nvited to her home off campus for a session on syntonics. She had a Syntonizer in her home and was an advocate for syntonics.

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