title: Enhancement of Corneal Visibility in Optical Coherence Tomography Images with Corneal Opacification.
abstract: OBJECTIVE
  To establish and to rank the performance of a corneal adaptive compensation (CAC) algorithm in enhancing corneal images with scars acquired from three commercially available anterior segment optical coherence tomography (ASOCT) devices.
  
  
  METHODS
  Horizontal B-scans of the cornea were acquired from 10 patients using three ASOCT devices (Spectralis, RTVue, and Cirrus). We compared ASOCT image quality (with and without CAC) by computing the intralayer contrast (a measure of shadow removal), the interlayer contrast (a measure of tissue boundary visibility), and the tissue/background contrast (a measure of overall corneal visibility). All six groups (Spectralis, RTVue, Cirrus, Spectralis+CAC, RTVue+CAC, and Cirrus+CAC) were ranked according to a global performance index that averaged all contrast quantities.
  
  
  RESULTS
  CAC provided mean intralayer contrasts improvement for all devices (allP< 0.05). Mean tissue/boundary contrasts were also improved for Spectralis and Cirrus (bothP< 0.001). Mean interlayer contrasts were increased for Spectralis (P= 0.011) only. When comparing global performance indices, all CAC groups outperformed their corresponding baseline groups significantly. RTVue performed best without CAC, but Spectralis+CAC was ranked first.
  
  
  CONCLUSIONS
  ASOCT images of corneal scars may be enhanced by CAC through shadow removal, improved tissue boundary visibility, and enhanced corneal visibility against the image background. RTVue produces the finest baseline images but the best image quality can be achieved by applying CAC to Spectralis images.
  
  
  CONCLUSIONS
  CAC could enhance visibility of corneal images with scars acquired from commercially available ASOCT devices and could aid preoperative planning of patients for ophthalmic procedures.
authors.affiliation: Ophthalmic Engineering and Innovation Laboratory, Department of Biomedical Engineering, Faculty of Engineering, National University of Singapore, Singapore.
authors.forename: Cheuk Wang
authors.initials: CW
authors.lastname: Chung
authors.affiliation: Singapore Eye Research Institute, Singapore ; Singapore National Eye Centre, Singapore.
authors.forename: Marcus
authors.initials: M
authors.lastname: Ang
authors.affiliation: Singapore National Eye Centre, Singapore.
authors.forename: Mohamed
authors.initials: M
authors.lastname: Farook
authors.affiliation: Singapore Eye Research Institute, Singapore ; NIHR Biomedical Research Centre, Moorfields Eye Hospital NHS Foundation Trust & UCL Institute of Ophthalmology, London, UK ; Discipline of Clinical Ophthalmology and Eye Health, University of Sydney, Sydney, NSW, Australia.
authors.forename: Nicholas G
authors.initials: NG
authors.lastname: Strouthidis
authors.affiliation: Singapore Eye Research Institute, Singapore ; Singapore National Eye Centre, Singapore ; Department of Clincal Sciences, Duke-NUS Graduate Medical School, Singapore.
authors.forename: Joddhbir S
authors.initials: JS
authors.lastname: Mehta
authors.affiliation: Université de la Polynésie française, Tahiti, French Polynesia.
authors.forename: Jean Martial
authors.initials: JM
authors.lastname: Mari
authors.affiliation: Ophthalmic Engineering and Innovation Laboratory, Department of Biomedical Engineering, Faculty of Engineering, National University of Singapore, Singapore ; Singapore Eye Research Institute, Singapore.
authors.forename: Michaël J A
authors.initials: MJ
authors.lastname: Girard
keywords: anterior segment optical coherence tomography; corneal adaptive compensation; corneal scar; image analysis