The incidence of extraocular muscle and cranial nerve palsy in orbital floor blow-out fractures.

The frequency of extraocular muscle (EOM) or cranial nerve (CN) palsy as the sole cause of diplopia in orbital floor blow-out fractures has not been previously determined. Of 40 blow-out fracture patients studied prospectively, seven had motility disturbances consistent with palsy of one EOM or CN. All seven patients had negative forced ductions, making entrapment, edema, or orbital hemorrhage unlikely causes of diplopia. The diplopia resolved in four patients in 1 year. Persistent diplopia is a common indication for repair of such fractures. If, however, diplopia is due only to EOM or CN palsy, orbital surgery should be deferred (in the absence of significant enophthalmos) in favor of observation and/or later strabismus surgery.