title: Automated Identification and Quantification of Subretinal Fibrosis in Neovascular Age-Related Macular Degeneration Using Polarization-Sensitive OCT.
abstract: OBJECTIVE
  To identify and quantify subretinal fibrosis in eyes with advanced neovascular age-related macular degeneration (nAMD) using polarization-sensitive optical coherence tomography (PS-OCT).
  
  
  METHODS
  Eyes of patients with subretinal fibrosis secondary to nAMD were included in this case series. All patients underwent a complete ophthalmic examination to clearly identify advanced nAMD lesions with fibrosis. Examinations of PS-OCT were performed using a novel system with an integrated eye tracker. Areas of fibrosis in PS-OCT, automatically segmented using a custom-built algorithm, were compared with conventional imaging modalities including spectral-domain OCT, fluorescein angiography, and color fundus photography in their potential to visualize fibrosis in nAMD.
  
  
  RESULTS
  Fifteen eyes of 15 consecutive patients were included. In polarization-sensitive OCT B-scans, a distinct "column-like" pattern was observed in averaged axis orientation images. En face analysis provided a precise mapping of the fibrotic scar component. Fibrous tissue was selectively identified by PS-OCT based on birefringence in all lesions, whereas in SD-OCT, subretinal hyperreflective material (SHRM) could not be further classified into scar tissue, fibrovascular material, or other AMD-specific material. Based on simultaneous polarization analyses in PS-OCT, the level of RPE alteration could be evaluated as well, showing thinning and loss of RPE associated with subretinal fibrosis.
  
  
  CONCLUSIONS
  Using PS-OCT, subretinal fibrosis can be identified as an intrinsically birefringent structure and can be segmented based solely on tissue-specific contrast. Polarization-sensitive OCT offers a unique method to identify clinically relevant components of SHRM (i.e., neovascular tissue versus fibrous tissue) and therefore allows for an optimized disease management and evaluation of therapeutic strategies.
authors.affiliation: Department of Ophthalmology and Optometry of the Medical University of Vienna Vienna, Austria.
authors.forename: Philipp
authors.initials: P
authors.lastname: Roberts
authors.affiliation: Center for Medical Physics and Biomedical Engineering of the Medical University of Vienna, Vienna, Austria 3Canon, Inc., Tokyo, Japan.
authors.forename: Mitsuro
authors.initials: M
authors.lastname: Sugita
authors.affiliation: Department of Ophthalmology and Optometry of the Medical University of Vienna Vienna, Austria.
authors.forename: Gábor
authors.initials: G
authors.lastname: Deák
authors.affiliation: Center for Medical Physics and Biomedical Engineering of the Medical University of Vienna, Vienna, Austria.
authors.forename: Bernhard
authors.initials: B
authors.lastname: Baumann
authors.affiliation: Center for Medical Physics and Biomedical Engineering of the Medical University of Vienna, Vienna, Austria.
authors.forename: Stefan
authors.initials: S
authors.lastname: Zotter
authors.affiliation: Center for Medical Physics and Biomedical Engineering of the Medical University of Vienna, Vienna, Austria.
authors.forename: Michael
authors.initials: M
authors.lastname: Pircher
authors.affiliation: Department of Ophthalmology and Optometry of the Medical University of Vienna Vienna, Austria.
authors.forename: Stefan
authors.initials: S
authors.lastname: Sacu
authors.affiliation: Center for Medical Physics and Biomedical Engineering of the Medical University of Vienna, Vienna, Austria.
authors.forename: Christoph K
authors.initials: CK
authors.lastname: Hitzenberger
authors.affiliation: Department of Ophthalmology and Optometry of the Medical University of Vienna Vienna, Austria.
authors.forename: Ursula
authors.initials: U
authors.lastname: Schmidt-Erfurth
mesh_terms: D000368:Aged; D004867:Equipment Design; D005260:Female; D005355:Fibrosis / Q000150:complications / Q000473:pathology / Q000503:physiopathology; D005451:Fluorescein Angiography; D005654:Fundus Oculi; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000295:instrumentation*; D008268:Macular Degeneration / Q000150:complications / Q000473:pathology* / Q000503:physiopathology; D008297:Male; D015203:Reproducibility of Results; D015861:Retinal Neovascularization / Q000150:complications / Q000473:pathology* / Q000503:physiopathology; D055213:Retinal Pigment Epithelium / Q000473:pathology*; D041623:Tomography, Optical Coherence / Q000379:methods*; D014792:Visual Acuity