A Metaphor for Phoria


number-4Ever wonder about the derivation of metaphors?  It has nothing to do with meeting a number.  The Latin word “phor” means carrier, and meta stems from the Greek “beyond”.  Hence, as elaborated greatly in the website metaphor-examples.com, a metaphor is a concept that builds a bridge to another concept.  This message was brought home brilliantly today by one of our vision help colleagues, Dr. Carl Hillier.

We were discussing the power of the metaphor in helping patients understand what we do.  Here is a powerful one that he mentioned, believed to have derived from one of his mentors, Dr. Bob Sanet.  We know that many people mistakenly equate having 20/20 eyesight with having “perfect vision”.  But 20/20 tells you no more about visual function than having a body temperature of 98.6 tells you about general health.  Your thermometer can show 98.6, yet you can be very, very sick.

phoria

Take phoria, for example.  That is a term used to indicate that one eye tends to drift excessively relative to the other eye.  Going back to the Latin derivative for “phor”, we might say that one eye tends to get carried away compared to the other eye.  Take a look at the graphic, beginning with eyes that an individual can maintain as aligned or in synch.  The middle frame shows the left eye drifting outward when a base out prism is introduced in front of the right eye.  But the person is able to exert enough effort to pull the left eye back inward and keep it in synch with the right eye, depicted in the bottom frame.  This tendency to drift out excessively, especially when reading or computing within arm’s length as when at a desk, called convergence insufficiency. Someone with a phoria can have big visual problems, even though their eyes look straight or normal under most conditions.  Straight eyes don’t necessarily tell the story, any more than 20/20 does, any more than 98.6 does.

Carl

2 thoughts on “A Metaphor for Phoria

  1. Quite appropriate Dr Press, just recently I’ve been able to give a precise name to my condition: “accomodative esotropia”.
    Before that, I was describing it like: “The act of focusing with one eye pulls the other in”.
    Once you know the name, you can find pertinent information and related concepts such as phoria, accomodation reflex, accomodative convergence, AC:C ratio.
    I’ve realized my amblyopic eye needs a much stronger prescription that was ever prescribed to me: something like +4 or greater, instead of +2. Because my eyes have always been assessed individually, and due to the effect of crowding, OTs had no clue on what prescription I really needed.
    Sometimes we’re better off on our own, as Kaplan says: take responsability for your own vision.

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