Assessment of Retinal Vascular Geometry (RVG) role in patients with neovascular Age Related Macular Degeneration (nAMD) participating in IVAN study

Habib, Maged, Al-Diri, Bashir, Scott, Lauren , Rogers, Chris, Reeves, Barney, Chakravarthy, Usha and Steel, David (2017) Assessment of Retinal Vascular Geometry (RVG) role in patients with neovascular Age Related Macular Degeneration (nAMD) participating in IVAN study. Investigative Opthalmology and Visual Science, 58 (8). ISSN 1552-5783

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Purpose : Previous studies have shown that differences in retinal vascular width are associated with development of early AMD, treatment with anti-vascular Endothelial Growth Factors (Anti VEGF) agents and can be predictive of treatment response; however it represents only a single parameter of the retinal vascular network. More detailed structural analysis of the RVG provides estimates of additional vascular network parameters.
This exploratory study evaluates whether RVG parameters can differentiate nAMD from fellow eyes at baseline, and if any RVG changes occur after Anti-VEGF treatment. We also assessed the predictive value of RVG for response to treatment.

Methods : The study analysed images of patients with nAMD treated with Anti-VEGF agents within the IVAN study using fully automated vascular analysis software.
The analysed RVG parameters included relative width ratios, bifurcating angles, area ratios, and optimality ratios. Data were collected at baseline, month 3 and 12 post treatment for eyes with nAMD and fellow eyes with no nAMD.
Structural response was defined as the presence or absence of intra retinal (IRF) or subretinal fluid (SRF) while functional response was defined as improvement of baseline visual acuity by 5 letters.
Mixed linear and logistic regression models were used for analysis of the RVG parameters.

Results : Images for 506 patients (505 study eyes with nAMD and 257 fellow eyes with no baseline nAMD) were analysed. Age was weakly associated with relative diameter of main daughter vessel, optimality ratio and optimality parameter. RVG parameter estimates did not differ for nAMD eyes and fellow eyes.
The predictive outcome models showed; increased within patient variation of the main vascular bifurcating angle at baseline (standard deviation SD) was associated with better structural outcome (Odds ratio OR for IRF/SRF= 0.93, 95% confidence interval (CI) 0.89 to 0.98) (p=0.002) and an increase in the SD of the smaller vessel branching angle at follow up was associated with better functional outcome (OR= 1.07, 95% CI 1.01 TO 1.13) (p=0.015)

Conclusions : The results showed clear signal that increased variations of the bifurcating angles parameters might be related to structural and functional outcomes illustrating the value of in-depth analysis of the retinal vascular network in management planning and monitoring of patients with AMD.

Additional Information:This is an open access article available online at This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License
Keywords:Retinal Vascular Geometry, Macular Degeneration, neovascular
Subjects:G Mathematical and Computer Sciences > G740 Computer Vision
Divisions:College of Science
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ID Code:31970
Deposited On:25 Oct 2018 14:07

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