Severe visual disturbance after exposure of the optic canal during intranasal ethmosphenoidectomy.

The cause of disturbed visual acuity associated with intranasal ethmosphenoidectomy is, on the one hand, a direct injury to the optic nerve. In this case, the disturbance in visual acuity develops immediately after the operation, and severe visual complications with a poor prognosis are found. On the other hand, in the two cases presented in this paper, the disturbed visual acuity develops postoperatively. In this case, it is necessary to take various possibilities into consideration, such as indirect effects of intraorbital bleeding, and damage to the lamina papyracea due to indirect and direct injury. Moreover, effects on the peri-optic nerve area and small blood vessels within the osseous optic canal should be considered. After thorough consideration and observation of the response to conservative therapy, such complications should be treated by investigating whether or not decompression of the optic nerve is effective.