title: Axonal loss in non-optic neuritis eyes of patients with multiple sclerosis linked to delayed visual evoked potential.
abstract: OBJECTIVE
  Recent studies demonstrate significant thinning of the retinal nerve fiber layer (RNFL) in multiple sclerosis (MS) non-optic neuritis (MS-NON) eyes. However, the pathologic basis of this reduction is not clear. The aim of the current study was to investigate the relationship of the RNFL thickness in MS-NON eyes with latency delay of the multifocal visual evoked potential (mfVEP), a surrogate marker of the visual pathway demyelination.
  
  
  METHODS
  Total and temporal RNFL thickness and latency of the mfVEP in 45 MS-NON eyes of 45 patients with relapsing-remitting MS and 25 eyes of age- and gender-matched controls were measured and analyzed.
  
  
  RESULTS
  There was significant reduction of total and temporal RNFL thickness (p = 0.015 and p = 0.006, respectively) and significant latency delay (p < 0.0001) in MS-NON eyes. Both total and temporal RNFL thickness were associated with latency of the mfVEP (r2 = 0.43, p < 0.0001 and r2 = 0.36, p = 0.001, respectively). MS-NON eyes with normal latency (n = 26) showed no significant reduction of RNFL thickness compared with controls (p = 0.44 and p = 0.1 for total and temporal RNFL, respectively), whereas eyes with delayed latency (n = 19) demonstrated significantly thinner RNFL (p = 0.001 and p = 0.0005). MS-NON eyes with delayed latency also had significantly thinner RNFL compared with those with normal latencies (p = 0.013 and p = 0.02). In patients with no previous optic neuritis in either eye, delayed latency and reduced RNFL were bilateral whenever present.
  
  
  CONCLUSIONS
  The study demonstrated significant association between RNFL loss and a latency delay of the mfVEP in MS-NON eyes.
authors.affiliation: Department of Ophthalmology, Save Sight Institute, University of Sydney, Australia. sasha@eye.usyd.edu.au
authors.forename: Alexandr
authors.initials: A
authors.lastname: Klistorner
authors.forename: Raymond
authors.initials: R
authors.lastname: Garrick
authors.forename: Michael H
authors.initials: MH
authors.lastname: Barnett
authors.forename: Stuart L
authors.initials: SL
authors.lastname: Graham
authors.forename: Hemamalini
authors.initials: H
authors.lastname: Arvind
authors.forename: Prema
authors.initials: P
authors.lastname: Sriram
authors.forename: Con
authors.initials: C
authors.lastname: Yiannikas
mesh_terms: D000328:Adult; D001369:Axons / Q000473:pathology*; D003711:Demyelinating Diseases / Q000473:pathology; D005074:Evoked Potentials, Visual; D005123:Eye / Q000473:pathology* / Q000503:physiopathology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D020528:Multiple Sclerosis, Chronic Progressive / Q000473:pathology* / Q000503:physiopathology*; D009443:Neuritis / Q000473:pathology* / Q000503:physiopathology; D012165:Retinal Ganglion Cells / Q000473:pathology; D055351:Retinal Neurons / Q000473:pathology; D041623:Tomography, Optical Coherence; D014795:Visual Pathways / Q000473:pathology