Retinal vessel diameter can reliably be determined in minipigs using Retinal Vessel Analyser with a microscope‐mounted fundus camera

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. Purpose: To study the effect of intravitreal (IVT) ranibizumab on the retinal arteriolar diameter in patients with neovascular age‐related macular degeneration (AMD). Methods: Ten eyes of 10 patients with previously untreated neovascular AMD were included. All eyes had three monthly IVT injections of ranibizumab and then were retreated as needed, based on visual acuity and optical coherence tomography (OCT) criteria. The diameter of the retinal arterioles was measured in vivo with a retinal vessel analyser (RVA) before the first IVT injection, 7 and 30 days after the first, the second and the third injection, and at month 12 of follow‐up. Results: A significant vasoconstriction of the retinal arterioles was observed following each one of the first three IVT injections of ranibizumab. Thirty days following the first, second and third injection, there was a mean decrease of 8.4 ± 3.2%, 11.9 ± 4.5% and 18.5 ± 7.2%, respectively, of the retinal arteriolar diameter compared with baseline (p < 0.01). At month 12, the vasoconstriction was still present with a mean decrease of 19.1 ± 8.3% of the retinal arteriolar diameter compared with baseline (p < 0.01). Median number of ranibizumab injections was 4 (range 3–10). There was no correlation between the number of injections and percentage diameter decrease at month 12 (r = −0.54, p > 0.1). There was no significant change in mean arterial pressure (MAP) during the period of follow‐up (p > 0.05). Conclusions: These results suggest that IVT ranibizumab induces sustained retinal arteriolar vasoconstriction in eyes with neovascular AMD.

Section: Retinal Arteriolar Diameter Measurementsmentioning

confidence: 99%

Long‐term results of the effect of intravitreal ranibizumab on the retinal arteriolar diameter in patients with neovascular age‐related macular degeneration

Mendrinos

Mangioris

Papadopoulou

et al. 2013

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“…As early as 1974, Parr and Spear proposed the central retinal equivalent for arteries (Parr & Spears 1974a,b) that was extended to retinal veins by Hubbard et al in 1999(Hubbard et al 1999. Later on, several computer-based measurements were programmed and evaluated in epidemiological as well as in clinical and experimental studies (Wong et al 2004;Benavent et al 2009;Cheung et al 2010;Garcia-Ortiz et al 2012;Papadopoulou et al 2012;Pemp et al 2013;Schuster et al 2013).…”

Section: Discussionmentioning

confidence: 97%

Optical coherence tomography‐based retinal vessel analysis for the evaluation of hypertensive vasculopathy

Schuster

Fischer

Vossmerbaeumer³

et al. 2014

“…Recently, reliable retinal vessel measurements in minipigs were demonstrated using a microscope‐mounted fundus camera that can be used in animal‐based research (Papadopoulou et al. ).…”

Section: Discussionmentioning

confidence: 99%

“…Blondal et al (2011) used an instrument primarily designed for retinal oximetry to monitor vessel diameters and found a remarkably low variance coefficient between 2.8% and 5.4%. Recently, reliable retinal vessel measurements in minipigs were demonstrated using a microscope-mounted fundus camera that can be used in animal-based research (Papadopoulou et al 2012).…”

Section: Discussionmentioning

confidence: 99%

Semi‐automated retinal vessel analysis in nonmydriatic fundus photography

Schuster

Fischer

Vossmerbaeumer

2013

ABSTRACT.Purpose: Funduscopic assessment of the retinal vessels may be used to assess the health status of microcirculation and as a component in the evaluation of cardiovascular risk factors. Typically, the evaluation is restricted to morphological appreciation without strict quantification. Our purpose was to develop and validate a software tool for semi-automated quantitative analysis of retinal vasculature in nonmydriatic fundus photography. Methods: MATLAB software was used to develop a semi-automated image recognition and analysis tool for the determination of the arterial-venous (A/V) ratio in the central vessel equivalent on 45°digital fundus photographs. Validity and reproducibility of the results were ascertained using nonmydriatic photographs of 50 eyes from 25 subjects recorded from a 3DOCT device (Topcon Corp.). Two hundred and thirty-three eyes of 121 healthy subjects were evaluated to define normative values. Results: A software tool was developed using image thresholds for vessel recognition and vessel width calculation in a semi-automated three-step procedure: vessel recognition on the photograph and artery/vein designation, width measurement and calculation of central retinal vessel equivalents. Mean vessel recognition rate was 78%, vessel class designation rate 75% and reproducibility between 0.78 and 0.91. Mean A/V ratio was 0.84. Application on a healthy norm cohort showed high congruence with prior published manual methods. Processing time per image was one minute. Conclusions: Quantitative geometrical assessment of the retinal vasculature may be performed in a semi-automated manner using dedicated software tools. Yielding reproducible numerical data within a short time leap, this may contribute additional value to mere morphological estimates in the clinical evaluation of fundus photographs.