title: Optical coherence tomography angiography and indocyanine green angiography for corneal vascularisation.
abstract: To describe an optical coherence tomography angiography (OCTA) system adapted for anterior segment imaging, compared with indocyanine green angiography (ICGA) in eyes with corneal vascularisation.
  
  
  
  Retrospective study of subjects with corneal vascularisation secondary to microbial keratitis who had OCTA scans performed using a commercially available split-spectrum amplitude-decorrelation algorithm angiography system (AngioVue; Optovue Inc., Fremont, California, USA) and ICGA images (Spectralis; Heidelberg Engineering, Heidelberg, Germany). The agreement between OCTA and ICGA techniques in terms of area of vascularisation measured, using Bland-Altman 95% limits of agreement (LOA).
  
  
  
  We compared the area of corneal vascularisation in 64 scan images (eight eyes, four scans for each angiography technique). In our series, the overall mean area of vascularisation from the ICGA scans was 0.49±0.34 mm2and OCTA scans was 0.51±0.36 mm2. We obtained substantial repeatability in terms of image quality score (κ=0.80) for all OCTA scans. The agreement between OCTA and ICGA scans was good, although ICGA measured a smaller area compared with the OCTA with a mean difference of -0.03 mm2(95% CI -0.07 to 0.01). The LOA ranged from a lower limit of -0.27 (95% CI -0.34 to -0.19) to an upper limit of 0.20 (95% CI 0.13 to 0.28, p=0.127).
  
  
  
  We found that rapid, non-contact OCTA adapted for the cornea was comparable with ICGA for measurement of the area of corneal vascularisation in this pilot clinical study. Further prospective studies are required to confirm if this relatively new imaging technique may be further developed to replace invasive angiography techniques for the anterior segment.
authors.affiliation: Singapore National Eye Center, Singapore Eye Research Institute, Singapore, Singapore.|Moorfields Eye Hospital NHS Foundation Trust, London, UK.
authors.forename: Marcus
authors.initials: M
authors.lastname: Ang
authors.affiliation: Moorfields Eye Hospital NHS Foundation Trust, London, UK.
authors.forename: Yijun
authors.initials: Y
authors.lastname: Cai
authors.affiliation: Moorfields Eye Hospital NHS Foundation Trust, London, UK.
authors.forename: Becky
authors.initials: B
authors.lastname: MacPhee
authors.affiliation: Moorfields Eye Hospital NHS Foundation Trust, London, UK.|Institute of Ophthalmology, University College London, London, UK.
authors.forename: Dawn A
authors.initials: DA
authors.lastname: Sim
authors.affiliation: Moorfields Eye Hospital NHS Foundation Trust, London, UK.|Institute of Ophthalmology, University College London, London, UK.
authors.forename: Pearse A
authors.identifier: 0000-0002-9239-745X
authors.initials: PA
authors.lastname: Keane
authors.affiliation: Singapore National Eye Center, Singapore Eye Research Institute, Singapore, Singapore.|Moorfields Eye Hospital NHS Foundation Trust, London, UK.|Department of Ophthalmology, National University Hospital, Singapore, Singapore.
authors.forename: Chelvin C A
authors.initials: CC
authors.lastname: Sng
authors.affiliation: Moorfields Eye Hospital NHS Foundation Trust, London, UK.|Institute of Ophthalmology, University College London, London, UK.
authors.forename: Catherine A
authors.initials: CA
authors.lastname: Egan
authors.affiliation: Moorfields Eye Hospital NHS Foundation Trust, London, UK.|Institute of Ophthalmology, University College London, London, UK.
authors.forename: Adnan
authors.initials: A
authors.lastname: Tufail
authors.affiliation: Moorfields Eye Hospital NHS Foundation Trust, London, UK.|Institute of Ophthalmology, University College London, London, UK.
authors.forename: Daniel F
authors.initials: DF
authors.lastname: Larkin
authors.affiliation: Moorfields Eye Hospital NHS Foundation Trust, London, UK.|Institute of Ophthalmology, University College London, London, UK.
authors.forename: Mark R
authors.initials: MR
authors.lastname: Wilkins
mesh_terms: D004396:Coloring Agents / Q000494:pharmacology; D003315:Cornea / Q000098:blood supply / Q000473:pathology*; D016510:Corneal Neovascularization / Q000175:diagnosis*; D005260:Female; D005451:Fluorescein Angiography / Q000379:methods*; D005500:Follow-Up Studies; D005654:Fundus Oculi; D006801:Humans; D007208:Indocyanine Green / Q000494:pharmacology*; D008297:Male; D008875:Middle Aged; D015203:Reproducibility of Results; D012189:Retrospective Studies; D041623:Tomography, Optical Coherence / Q000379:methods*
chemical_list: D004396:Coloring Agents; D007208:Indocyanine Green
keywords: Cornea; Imaging; Neovascularisation