PPRuNe Forums - View Single Post - Exophoria and Exotropia and Strabismus- Aren't they the same?!
Old 23rd Jun 2009, 09:29
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David Horn
Join Date: May 2007
Location: Manchester, UK
Age: 34
Posts: 128
"Phorias" and "Tropias" are different things. A phoria is a tendency for one (or both) eyes to deviate if fusion cannot be maintained. So, for example, if you covered one eye the other might turn inwards or outwards.

This is where the "exo" and "eso" come in. They're from the Greek meaning "out" and "in". So an exophoria would be the tendency for an eye to turn outwards when fusion is broken. For reference, hyperphoria refers to the vertical plane. (I think.)

A tropia, on the other hand, is a manifest defect in the eye and is a constant imbalance pulling the eye in or out. Strabismus = squint = general term.

I believe the CAA have issues with phorias because of the potential for double vision to occur, whereas with a tropia the patient is generally adapted to it and the risk of double vision is tiny.

I had a pretty bad squint (exotropia) corrected with surgery. No complications and the CAA handed me my Class 1 about 3 months after the operation. The consultant had to write them a report but that was about it.

The head optometrist at the CAA is a fantastic guy and incredibly supportive. Best thing to do is ask your own optometrist for a report and send it off to the CAA and see what they say.

Best of luck,


PS - Apologies if I've screwed up any of my definitions. ;-)
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