A case history is presented of a patient who sustained visual loss and a third-nerve palsy after the application of monopolar electrocautery to the orbital apex. Because the third-nerve palsy resolved and most of the vision was regained, it is theorized that the neurological deficits were secondary to myelin damage caused by the monopolar electrocoagulator. The purpose of this article is to compare the effects of monopolar electrocoagulation, bipolar electrocoagulation, and hot-wire cautery on decompressed optic nerves of cats. Although all three forms of coagulation are capable of causing demyelination within the optic nerve when used on the nerve sheath, mono-polar electrocoagulation resulted in the greatest degree of demyelination and bipolar electrocoagulation resulted in the least demyelination.