I certainly agree that orbital compartment syndrome is a clinical diagnosis.
Sometimes, though, traumatic proptosis with vision loss can be found in the setting of open globe/commotio retinae/traumatic optic neuropathy....any of which can be associated with significant edema as opposed to hemorrhage.
If I'm not mistaken (but I certainly could be mistaken, so I am willing to learn), I don't think a lateral canthotomy/inferior cantholysis is indicated in those conditions. Then again, like you point out, orbital compartment syndrome is a clinical diagnosis and perhaps expression of the edematous fluid is indicated?
Thanks for opening up the discussion. I'm curious about how many others have gotten to do this procedure.