title: Enhanced Visualization of Subtle Outer Retinal Pathology by En Face Optical Coherence Tomography and Correlation with Multi-Modal Imaging.
abstract: OBJECTIVE
  To present en face optical coherence tomography (OCT) images generated by graph-search theory algorithm-based custom software and examine correlation with other imaging modalities.
  
  
  METHODS
  En face OCT images derived from high density OCT volumetric scans of 3 healthy subjects and 4 patients using a custom algorithm (graph-search theory) and commercial software (Heidelberg Eye Explorer software (Heidelberg Engineering)) were compared and correlated with near infrared reflectance, fundus autofluorescence, adaptive optics flood-illumination ophthalmoscopy (AO-FIO) and microperimetry.
  
  
  RESULTS
  Commercial software was unable to generate accurate en face OCT images in eyes with retinal pigment epithelium (RPE) pathology due to segmentation error at the level of Bruch's membrane (BM). Accurate segmentation of the basal RPE and BM was achieved using custom software. The en face OCT images from eyes with isolated interdigitation or ellipsoid zone pathology were of similar quality between custom software and Heidelberg Eye Explorer software in the absence of any other significant outer retinal pathology. En face OCT images demonstrated angioid streaks, lesions of acute macular neuroretinopathy, hydroxychloroquine toxicity and Bietti crystalline deposits that correlated with other imaging modalities.
  
  
  CONCLUSIONS
  Graph-search theory algorithm helps to overcome the limitations of outer retinal segmentation inaccuracies in commercial software. En face OCT images can provide detailed topography of the reflectivity within a specific layer of the retina which correlates with other forms of fundus imaging. Our results highlight the need for standardization of image reflectivity to facilitate quantification of en face OCT images and longitudinal analysis.
authors.affiliation: Centre for Ophthalmology and Visual Science, The University of Western Australia, Crawley, Western Australia, Australia.|Lions Eye Institute, Nedlands, Western Australia, Australia.
authors.forename: Danuta M
authors.initials: DM
authors.lastname: Sampson
authors.affiliation: Contact Lens and Visual Optics Laboratory, School of Optometry and Vision Science, Queensland University of Technology, Brisbane, Queensland, Australia.
authors.forename: David
authors.initials: D
authors.lastname: Alonso-Caneiro
authors.affiliation: Centre for Ophthalmology and Visual Science, The University of Western Australia, Crawley, Western Australia, Australia.|Lions Eye Institute, Nedlands, Western Australia, Australia.
authors.forename: Avenell L
authors.initials: AL
authors.lastname: Chew
authors.affiliation: Centre for Ophthalmology and Visual Science, The University of Western Australia, Crawley, Western Australia, Australia.|Department of Medical Technology and Physics, Sir Charles Gairdner Hospital, Hospital Ave, Nedlands, Western Australia, Australia.
authors.forename: Tina
authors.initials: T
authors.lastname: Lamey
authors.affiliation: Department of Medical Technology and Physics, Sir Charles Gairdner Hospital, Hospital Ave, Nedlands, Western Australia, Australia.
authors.forename: Terri
authors.initials: T
authors.lastname: McLaren
authors.affiliation: Centre for Ophthalmology and Visual Science, The University of Western Australia, Crawley, Western Australia, Australia.|Department of Medical Technology and Physics, Sir Charles Gairdner Hospital, Hospital Ave, Nedlands, Western Australia, Australia.
authors.forename: John
authors.initials: J
authors.lastname: De Roach
authors.affiliation: Centre for Ophthalmology and Visual Science, The University of Western Australia, Crawley, Western Australia, Australia.|Lions Eye Institute, Nedlands, Western Australia, Australia.|Department of Ophthalmology, Royal Perth Hospital, Perth, Western Australia, Australia.
authors.forename: Fred K
authors.identifier: http://orcid.org/0000-0003-2809-9930
authors.initials: FK
authors.lastname: Chen
mesh_terms: D000328:Adult; D000465:Algorithms; D016570:Bruch Membrane / Q000473:pathology; D005260:Female; D005451:Fluorescein Angiography; D064368:Healthy Volunteers; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D007091:Image Processing, Computer-Assisted; D008875:Middle Aged; D064847:Multimodal Imaging; D009887:Ophthalmoscopy; D055095:Optics and Photonics; D012160:Retina / Q000000981:diagnostic imaging* / Q000473:pathology; D055213:Retinal Pigment Epithelium / Q000000981:diagnostic imaging* / Q000473:pathology; D012984:Software; D019265:Spectroscopy, Near-Infrared; D041623:Tomography, Optical Coherence