Assessment of retinal vascular calibres as a biomarker of disease activity in birdshot chorioretinopathy

Abstract

Purpose 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. Conclusion 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.

Retinal Capillary Density in Patients With Birdshot Chorioretinopathy

“…Recently, Agrawal et al measured retinal vascular calibers in BCR patients and reported significantly impaired calibers only in the retinal venules compared to a healthy control group. 17 This finding suggests that microvascular inflammatory damage in BCR is primarily present in the venous arm.…”

Lower fractal dimension of retinal vessel for patients with Birdshot chorioretinopathy

“…Although our study failed to show any significant difference in CRAE, CRVE and AVR according to BSCR, Agrawal et al reported narrowing of retinal veins using the IVAN software (for n = 21 patients). (Agrawal et al, 2017) In this latter study, CRVE values were significantly lower for BSCR patients (211.3 μm) than in controls (227.9 μm). There was no evidence of significant for the CRAE between the two groups.…”

Heritability of Retinal Vascular Fractals: A Twin Study

“…intrinsic vascular characteristics. Vascular patterns vary with extraocular factors, such as blood pressure, 32 and hematocrit, 33 and with local factors, such as retinal vein occlusion, 34 uveitis, 35 and diabetic retinopathy. 36 Consequently, the heritability of the retinal vascular fractal dimension could be mediated by other factors than the heritability of vascular characteristics, especially such systemic factors as the heritability of blood pressure control mechanisms.…”