Visual evoked potential monitoring of optic nerve function during surgery.
A study was made with intra-operative flash--visual evoked potentials (VEP) monitored using a fibre-optic/contact lens photo stimulator in 57 patients undergoing intra-orbital surgical procedures with potential risk to the optic nerve. The VEPs recorded under enflurane and nitrous oxide anaesthesia did not differ significantly in latency or amplitude from the pre-operative recordings. Transient abolition of the VEP was seen under many circumstances and did not correlate with the outcome of surgery, but absence of a previously normal VEP for more than four minutes during surgical manipulation within the orbit did show a correlation with post operative impairment of vision. The technique provides early warning to the surgeon of threats to the integrity of the optic nerve.
Harding
G F
GF
Department of Vision Sciences, University of Aston, Birmingham, United Kingdom.
Bland
J D
JD
Smith
V H
VH
D000293:Adolescent; D000328:Adult; D000368:Aged; D003261:Contact Lenses; D005074:Evoked Potentials, Visual / Q000502:physiology*; D005260:Female; D006111:Graves Disease / Q000601:surgery; D006801:Humans; D007431:Intraoperative Complications / Q000503:physiopathology*; D007511:Ischemia / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D009408:Nerve Compression Syndromes / Q000601:surgery*; D009900:Optic Nerve / Q000098:blood supply / Q000503:physiopathology*; D009901:Optic Nerve Diseases / Q000601:surgery*; D009916:Orbital Diseases / Q000601:surgery*; D010775:Photic Stimulation / Q000295:instrumentation; D011183:Postoperative Complications / Q000503:physiopathology; D014792:Visual Acuity / Q000502:physiology