title: Morphologic changes and functional retinal impairment in patients with Parkinson disease without visual loss.
abstract: OBJECTIVE
  To investigate the anatomic and electrophysiologic changes of the macula and the optic nerve in patients with Parkinson disease (PD) without visual impairment.
  
  
  METHODS
  Thirty-two eyes of 16 patients with PD (group A) without visual impairment were tested. Visual acuity was 20/20 or better and visual fields as well as color vision testing results were normal. Also, no retinal lesions were assessed. Patients in group B (40 eyes of 20 patients) were age- and sex-matched control subjects. All study participants underwent a comprehensive ophthalmic examination, multifocal electroretinogram (mfERG) recording, and optical coherence tomography (OCT) scan. Thickness of retinal nerve fiber layer (RNFL) along a 3.4-mm-diameter circle centered on the optic nerve head was evaluated using third-generation OCT.
  
  
  RESULTS
  The mean P1-response density amplitude of ring 1 of mfERG was 136.69 nV/deg2 in patients with PD and 294 nV/deg2 in control subjects and the difference was highly significant. On the contrary, these values in ring 2 and 3 did not differ statistically between controls and patients with PD. The mean inferior and temporal RNFL thickness was significantly lower in patients with PD than in control subjects (p<0.0001 and p=0.0045, respectively).
  
  
  CONCLUSIONS
  In patients with PD with normal vision, we found a decrease in the electrical activity of the fovea as well as in the thickness of the RNFL. Multifocal electroretinogram and OCT scan objectively detect early subclinical PD-associated visual functional impairment.
authors.affiliation: Department of Ophthalmology, University of Athens, Athens, Greece. mosxosmix@ath.forthnet.gr
authors.forename: Marilita M
authors.initials: MM
authors.lastname: Moschos
authors.forename: Georgios
authors.initials: G
authors.lastname: Tagaris
authors.forename: Ioannis
authors.initials: I
authors.lastname: Markopoulos
authors.forename: Ioannis
authors.initials: I
authors.lastname: Margetis
authors.forename: Stylianos
authors.initials: S
authors.lastname: Tsapakis
authors.forename: Menelaos
authors.initials: M
authors.lastname: Kanakis
authors.forename: Chrysanthi
authors.initials: C
authors.lastname: Koutsandrea
mesh_terms: D055253:Color Vision / Q000502:physiology; D004596:Electroretinography; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009412:Nerve Fibers / Q000473:pathology*; D010300:Parkinson Disease / Q000175:diagnosis / Q000503:physiopathology*; D010865:Pilot Projects; D012160:Retina / Q000503:physiopathology*; D012164:Retinal Diseases / Q000175:diagnosis / Q000503:physiopathology*; D012165:Retinal Ganglion Cells / Q000473:pathology*; D041623:Tomography, Optical Coherence; D014786:Vision Disorders / Q000175:diagnosis / Q000503:physiopathology*; D014792:Visual Acuity / Q000502:physiology*; D014794:Visual Fields / Q000502:physiology; D019987:Persons with Visual Disabilities