title: Outer retinal changes following acute optic neuritis.
abstract: BACKGROUND
  Retinal nerve fiber and ganglion cell+inner plexiform (GCIP) layer thinning following multiple sclerosis-related acute optic neuritis (AON) is well described. However, whether AON results in changes in the inner nuclear (INL), outer plexiform (OPL), outer nuclear (ONL) and/or photoreceptor segment (PS) layers remains undetermined.
  
  
  OBJECTIVE
  The objective of this paper is to determine if INL+OPL and/or ONL+PS changes occur following AON.
  
  
  METHODS
  Thirty-three AON patients underwent serial optical coherence tomography (OCT) and visual function testing (mean follow-up: 25 months). Longitudinal changes in retinal layer thickness were analyzed using mixed-effects linear regression.
  
  
  RESULTS
  Four months following AON, the mean decrease in GCIP thickness relative to baseline was 11.4% (p < 0.001). At four months, a concomitant 3.4% increase in average ONL+PS thickness was observed (p < 0.001). The percentage decrease in GCIP thickness and increase in ONL+PS thickness were strongly correlated (r = -0.70; p < 0.001). Between months 4 to 12, ONL+PS thickness declined and, at 12 months, was no longer significantly different from baseline (mean change: 0.5%; p = 0.37). Similar, albeit less robust, changes in the INL+OPL were observed.
  
  
  CONCLUSIONS
  Following AON, dynamic changes occur in the deep retinal layers, which are proportional to GCIP thinning. These novel findings help further our understanding of the biological and/or anatomical sequelae resulting from AON.
authors.affiliation: Department of Neuroimmunology and Neuroinfectious Disorders, Johns Hopkins School of Medicine, USA.
authors.forename: Omar A
authors.initials: OA
authors.lastname: Al-Louzi
authors.affiliation: Department of Neuroimmunology and Neuroinfectious Disorders, Johns Hopkins School of Medicine, USA.
authors.forename: Pavan
authors.initials: P
authors.lastname: Bhargava
authors.affiliation: Department of Neuroimmunology and Neuroinfectious Disorders, Johns Hopkins School of Medicine, USA.
authors.forename: Scott D
authors.initials: SD
authors.lastname: Newsome
authors.affiliation: Department of Neurology, New York University-Langone Medical Center, USA.
authors.forename: Laura J
authors.initials: LJ
authors.lastname: Balcer
authors.affiliation: Departments of Neurology and Ophthalmology, University of Texas Southwestern, USA.
authors.forename: Elliot M
authors.initials: EM
authors.lastname: Frohman
authors.affiliation: Department of Biostatistics, Johns Hopkins Bloomberg School of Public Health, USA.
authors.forename: Ciprian
authors.initials: C
authors.lastname: Crainiceanu
authors.affiliation: Department of Neuroimmunology and Neuroinfectious Disorders, Johns Hopkins School of Medicine, USA.
authors.forename: Peter A
authors.initials: PA
authors.lastname: Calabresi
authors.affiliation: Department of Neuroimmunology and Neuroinfectious Disorders, Johns Hopkins School of Medicine, USA ssaidha2@jhmi.edu.
authors.forename: Shiv
authors.initials: S
authors.lastname: Saidha
mesh_terms: D000328:Adult; D005260:Female; D006801:Humans; D008297:Male; D009902:Optic Neuritis / Q000000981:diagnostic imaging* / Q000473:pathology / Q000503:physiopathology; D012160:Retina / Q000473:pathology; D012165:Retinal Ganglion Cells / Q000473:pathology*; D041623:Tomography, Optical Coherence; D014792:Visual Acuity
keywords: Multiple sclerosis; optic nerve injuries; optic neuritis; optical coherence tomography; retinal ganglion cells; retinal photoreceptors