Abstract
Abstract: :
Purpose: Rhinogenic optic neuropathy is a clinical entity that includes rhinogenous optic neuritis and optic neuropathy and is caused by a paranasal cyst. The damage to the optic nerve is believed to result mainly from compression and inflammation. We investigated the characteristics of the pattern visually evoked potentials ( PVEP ) in patients with rhinogenic optic neuropathy. Methods: In three cases of rhinogenic optic neuropathy, we recorded the visual acuity and transient PVEPs, and performed MRI. All patients underwent surgery within 3 days of the onset, and the recovery was immediate and satisfactory. To record PVEPs, a silver-cup electrode was placed at Oz and was referred to the earlobe. The stimulus pattern was a 30 minutes of arc black and white checkerboard with 80% contrast and reversal; at 3/sec. Results: In all cases, cysts by mucocele were observed in the sphenoid sinus by MRI, and in one case, the optic nerve showed high intensity in T2 weighted images. In the 2 cases without optic nerve change by MRI the P100 peak latency and visual acuity had recovered to normal on the day after surgery. In the case with optic nerve change, the visual acuity recovered on the next day but the recovery of the P100 peak latency was delayed. Conclusions: Surgical intervention leads to rapid recovery of PVEP and visual acuity in cases of rhinogenic optic neuropathy. The PVEP findings in the 2 cases that showed rapid recovery differed from the characteristics of the PVEP in optic neuritis. These findings indicate that in rhinogenic optic neuropathy, the damage to the optic nerve can be caused by mechanical compression or mechanical compression with inflammation
Keywords: neuro-ophthalmology: optic nerve • electrophysiology: clinical • inflammation