title: Characterization of retinal architecture in Parkinson's disease.
abstract: BACKGROUND
  Parkinson's disease (PD) is a neurodegenerative disorder associated with dopaminergic cell loss and α-synuclein aggregation in Lewy bodies, which has been demonstrated in the retina.
  
  
  METHODS
  We performed a spectral-domain optical coherence tomography (OCT) study in patients with PD and healthy controls to measure the peripapillary retinal nerve fiber layer thickness and macular volume. Intra-retinal segmentation was performed to measure the volume of the retinal nerve fiber (RNFL), ganglion cell (GCL), inner plexiform (IPL), inner nuclear (INL), outer plexiform (OPL), and outer nuclear (ONL) layers. Analysis was carried out blinded to the clinical status of study participants.
  
  
  RESULTS
  101 PD and 46 healthy control eyes were included in the study. In PD patients, peripapillary retinal nerve fiber layer was not significantly thinner (96.95 μm vs 94.42 μm, p=0.08) but macular volume was (8.58 mm3 vs 8.33 mm3, p=0.0002). Intra-retinal segmentation showed that PD subjects have reduced GCL, IPL, INL and ONL volumes. In contrast, the OPL volume was significantly increased (0.81 mm3 vs 0.78 mm3 p=0.0214).
  
  
  CONCLUSIONS
  Thickening of the OPL is a novel finding which may correspond to the localization of α-synuclein in the OPL of PD patients. We hypothesize that the enlargement of the OPL may represent a potential biomarker of α-synuclein aggregation in PD. This may have significant clinical implications.
authors.affiliation: Sastry Foundation Advanced Imaging Laboratory, Detroit, United States.
authors.forename: Jessica
authors.initials: J
authors.lastname: Chorostecki
authors.affiliation: Sastry Foundation Advanced Imaging Laboratory, Detroit, United States.
authors.forename: Navid
authors.initials: N
authors.lastname: Seraji-Bozorgzad
authors.affiliation: Sastry Foundation Advanced Imaging Laboratory, Detroit, United States.
authors.forename: Aashka
authors.initials: A
authors.lastname: Shah
authors.affiliation: Sastry Foundation Advanced Imaging Laboratory, Detroit, United States.
authors.forename: Fen
authors.initials: F
authors.lastname: Bao
authors.affiliation: Sastry Foundation Advanced Imaging Laboratory, Detroit, United States.
authors.forename: Ginny
authors.initials: G
authors.lastname: Bao
authors.affiliation: Movement Disorders Center, Department of Neurology, Wayne State University School of Medicine, Detroit, United States.
authors.forename: Edwin
authors.initials: E
authors.lastname: George
authors.affiliation: Movement Disorders Center, Department of Neurology, Wayne State University School of Medicine, Detroit, United States.
authors.forename: Veronica
authors.initials: V
authors.lastname: Gorden
authors.affiliation: Sastry Foundation Advanced Imaging Laboratory, Detroit, United States.
authors.forename: Christina
authors.initials: C
authors.lastname: Caon
authors.affiliation: Department of Neurology, University of Texas Southwestern, Dallas, United States.
authors.forename: Elliot
authors.initials: E
authors.lastname: Frohman
authors.affiliation: Department of Ophthalmology, Duke Eye Center and Duke University Medical Center, Durham, United States; Department of Neurology, Duke Eye Center and Duke University Medical Center, Durham, United States.
authors.forename: M Tariq
authors.initials: MT
authors.lastname: Bhatti
authors.affiliation: Sastry Foundation Advanced Imaging Laboratory, Detroit, United States. Electronic address: okhan@med.wayne.edu.
authors.forename: Omar
authors.initials: O
authors.lastname: Khan
mesh_terms: D000368:Aged; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009412:Nerve Fibers / Q000473:pathology*; D010300:Parkinson Disease / Q000473:pathology*; D012160:Retina / Q000473:pathology*; D041623:Tomography, Optical Coherence
keywords: Alpha-synuclein; Dopamine; Optical coherence tomography; Parkinson's disease; Retina