title: Assessment of retinal vascular calibres as a biomarker of disease activity in birdshot chorioretinopathy.
abstract: OBJECTIVE
  Birdshot chorioretinopathy (BCR) is a potentially blinding ocular disorder involving the retinal vasculature and choroid without any systemic manifestations. The objective of the study was to describe vascular calibre changes in BCR and analyse the possibility of this optical biomarker for staging and monitoring disease activity in BCR.
  
  
  METHODS
  This retrospective case-control study at a tertiary referral eye centre in the UK included 33 eyes from 21 patients with BCR and equal number of eyes from control subjects. Diagnosis of BCR was confirmed on fundus fluorescein and indocyanine green angiography. Vascular calibres were measured using validated semiautomated software.
  
  
  RESULTS
  Patients with BCR had smaller retinal venular calibres central retinal venular equivalent (CRVE) than controls (211.3 versus 227.9 μm, p = 0.008). After adjusting for variables, the difference between the two groups for CRVE at baseline was statistically significant based on two different analysis methods. Central retinal venular equivalent (CRVE) was lower at the 6-month follow-up visit (206.2 versus 213.8 μm, p-value = 0.03), and arteriole-to-venule ratio was larger (0.74 versus 0.71, p = 0.04) in subjects with BCR. Arteriolar calibre (CRAE) remained the same.
  
  
  CONCLUSIONS
  This study provides novel insight into the pattern of vascular involvement in BCR. There was significant difference in the CRVE in patients with BCR. More studies are needed to correlate this data with visual function and treatment outcome and to validate the findings.
authors: Moorfields Eye Hospital, NHS Foundation Trust, London, UK.|Biomedical Research Centre, UCL Institute of Ophthalmology, London, UK.|National Healthcare Group Eye Institute, Tan Tock Seng Hospital, Singapore.
authors: Rupesh
authors: R
authors: Agrawal
authors: Center for Vision Research, Westmead Millennium Institute, University of Sydney, Sydney, New South Wales, Australia.
authors: Nichole
authors: N
authors: Joachim
authors: Singapore Eye Research Institute, Singapore National Eye Centre, Singapore.|Duke-NUS Graduate Medical School, Singapore.
authors: Ling-Jun
authors: LJ
authors: Li
authors: National Healthcare Group Eye Institute, Tan Tock Seng Hospital, Singapore.
authors: Jiaying
authors: J
authors: Lee
authors: Stanley M. Truhlsen Eye Institute, University of Nebraska Medical Center, Omaha, Nebraska, USA.
authors: Aniruddha
authors: A
authors: Agarwal
authors: Moorfields Eye Hospital, NHS Foundation Trust, London, UK.|Biomedical Research Centre, UCL Institute of Ophthalmology, London, UK.
authors: Dawn A
authors: DA
authors: Sim
authors: Moorfields Eye Hospital, NHS Foundation Trust, London, UK.|Biomedical Research Centre, UCL Institute of Ophthalmology, London, UK.
authors: Pearse A
authors: PA
authors: Keane
authors: Moorfields Eye Hospital, NHS Foundation Trust, London, UK.|Center for Vision Research, Westmead Millennium Institute, University of Sydney, Sydney, New South Wales, Australia.
authors: Gerald
authors: G
authors: Liew
authors: Moorfields Eye Hospital, NHS Foundation Trust, London, UK.|Biomedical Research Centre, UCL Institute of Ophthalmology, London, UK.
authors: Carlos E
authors: CE
authors: Pavesio
mesh_terms: D000080365:Birdshot Chorioretinopathy; D002825:Chorioretinitis / Q000175:diagnosis* / Q000503:physiopathology; D018450:Disease Progression; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D010781:Photography; D012160:Retina / Q000000981:diagnostic imaging*; D012161:Retinal Artery / Q000000981:diagnostic imaging*; D012169:Retinal Vein / Q000000981:diagnostic imaging*; D012189:Retrospective Studies; D012720:Severity of Illness Index
keywords: birdshot chorioretinopathy; chorioretinitis; propensity score; retinal vessel calibre; uveitis; vasculitis