title: Multifocal visual evoked potentials in unilateral compressive optic neuropathy secondary to orbital tumors.
abstract: OBJECTIVE
  To evaluate the effects of unilateral compressive optic neuropathy secondary to orbital tumors and the removal of the tumors on amplitude and latency of multifocal visual evoked potentials (mfVEPs) and to compare these responses with visual ﬁeld defects seen on static automated perimetry.
  
  
  METHODS
  Static automated and mfVEP recordings were obtained from 14 patients with orbital tumors affecting one optic nerve. Monocular and interocular amplitude and latency analyses were performed.
  
  
  RESULTS
  The change in the mfVEP amplitude agreed with visual field findings with regard to topography and severity of deviation from normal in 10 patients. For 4 patients with normal visual field, the changes in the mfVEP were of significance. The delay in recordable responses from affected eyes ranged from 2.56 to 18.28 ms (interocular analysis) and 0.1 to 21.86 ms (monocular analysis). Ten patients whose tumor was totally removed showed a recovery of the visual ﬁeld and mfVEP to various degrees. Visual field of 6 patients showed within normal limits after total removal of the tumor, and the defects of mfVEP in 3 patients remained apparent, while the mfVEP of the other 3 patients showed a complete recovery.
  
  
  CONCLUSIONS
  Various orbital tumors can cause compressive optic neuropathy. Compressive optic neuropathy secondary to orbital tumors results in mfVEP amplitude reduction and latency prolongation. The changes in measures of mfVEP due to orbital tumors are consistent with the visual ﬁeld changes in most patients. In some patients, the subjective visual ﬁeld results and objective mfVEP are discordant. The objective changes of mfVEP may appear earlier than the defect of visual field, and thus it may be able to identify subtle defects that are undetectable with Humphrey perimetry. Postoperatively, recovery of the mfVEP may be later than that of visual field in some patients. The mfVEP changes may assist in both early diagnosis and follow-up of the compressive optic neuropathy secondary to orbital tumors.
authors.affiliation: Department of Ophthalmology, Eye, Ear, Nose, and Throat Hospital of Fudan University, Shanghai, China.
authors.forename: Kang
authors.initials: K
authors.lastname: Xue
authors.forename: Min
authors.initials: M
authors.lastname: Wang
authors.forename: Jiang
authors.initials: J
authors.lastname: Qian
authors.forename: Yifei
authors.initials: Y
authors.lastname: Yuan
authors.forename: Rui
authors.initials: R
authors.lastname: Zhang
mesh_terms: D000328:Adult; D005074:Evoked Potentials, Visual / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009408:Nerve Compression Syndromes / Q000209:etiology / Q000503:physiopathology*; D009901:Optic Nerve Diseases / Q000209:etiology / Q000503:physiopathology*; D009918:Orbital Neoplasms / Q000150:complications*; D012189:Retrospective Studies; D014792:Visual Acuity; D055815:Young Adult