Comparing Measurements of Vascular Diameter Using Adaptative Optics Imaging and Conventional Fundus Imaging

The aim of this prospective study was to compare retinal vascular diameter measurements taken from standard fundus images and adaptive optics (AO) images. We analysed retinal images of twenty healthy subjects with 45-degree funduscopic colour photographs (CR-2 Canon fundus camera, Canon™) and adaptive optics (AO) fundus images (rtx1 camera, Imagine Eyes(®)). Diameters were measured using three software applications: the VAMPIRE (Vessel Assessment and Measurement Platform for Images of the REtina) annotation tool, IVAN (Interactive Vessel ANalyzer) for funduscopic colour photographs, and AO_Detect_Artery™ for AO images. For the arterial diameters, the mean difference between AO_Detect_Artery™ and IVAN was 9.1 µm (−27.4 to 9.2 µm, p = 0.005) and the measurements were significantly correlated (r = 0.79). The mean difference between AO_Detect_Artery™ and VAMPIRE annotation tool was 3.8 µm (−34.4 to 26.8 µm, p = 0.16) and the measurements were poorly correlated (r = 0.12). For the venous diameters, the mean difference between the AO_Detect_Artery™ and IVAN was 3.9 µm (−40.9 to 41.9 µm, p = 0.35) and the measurements were highly correlated (r = 0.83). The mean difference between the AO_Detect_Artery™ and VAMPIRE annotation tool was 0.4 µm (−17.44 to 25.3 µm, p = 0.91) and the correlations were moderate (r = 0.41). We found that the VAMPIRE annotation tool, an entirely manual software, is accurate for the measurement of arterial and venular diameters, but the correlation with AO measurements is poor. On the contrary, IVAN, a semi-automatic software tool, presents slightly greater differences with AO imaging, but the correlation is stronger. Data from arteries should be considered with caution, since IVAN seems to significantly under-estimate arterial diameters

Retinal Vessel Phenotype In Patients With Primary Open-Angle Glaucoma

International audiencePURPOSE: To characterize the phenotype of retinal vessels using central retinal artery equivalent (CRAE), central retinal vein equivalent (CRVE), tortuosity and fractal dimension (FD) in primary open-angle glaucoma (POAG) subjects. METHODS: This prospective case-control multicentre study included 61 POAG subjects and 61 controls matched for age, systemic hypertension and body mass index. Fundus images of the right eye were acquired using a non-mydriatic camera. Central retinal artery equivalent (CRAE), CRVE, arteriole-to-venule ratio, FD and tortuosity of the vascular network were measured using VAMPIRE software (Vessel Assessment and Measurement Platform for Images of the Retina). Primary open-angle glaucoma (POAG) patients underwent 24.2 sita-standard visual field and peri-papillary optical coherence tomography (OCT) examinations. Data were expressed as median and interquartile range (75-25th percentiles). RESULTS: The control group was comparable to the POAG group for sex ratio, refraction and intraocular pressure. The mean CRAE and the mean CRVE were significantly lower in the POAG group than in the control group [150.5 (137.9; 157.1) mum versus 161.3 (154.0; 168.4) mum and 204.8 (190.1; 218.1) mum versus 233.5 (222.3; 246.9) mum, respectively; p < 0.001] and for fractal parameters as well. No significant difference was found for tortuosity between the two groups. There was a significant correlation between CRAE and retinal nerve fibre layer (RNFL) thickness (r = 0.27; p = 0.03). VAMPIRE parameters were not correlated with visual field indices. CONCLUSION: Primary open-angle glaucoma (POAG) was associated with a narrowing of arterial and venous retinal vessels, a higher arteriole-to-venule ratio and lower values of FD. The relationship between CRAE and RNFL thickness needs further investigation

Concordance between SIVA, IVAN, and VAMPIRE software tools for semi-automated analysis of retinal vessel caliber

We aimed to compare measurements from three of the most widely used software packages in the literature and to generate conversion algorithms for measurement of the central retinal artery equivalent (CRAE) and central retinal vein equivalent (CRVE) between SIVA and IVAN and between SIVA and VAMPIRE. We analyzed 223 retinal photographs from 133 human participants using both SIVA, VAMPIRE and IVAN independently for computing CRAE and CRVE. Agreement between measurements was assessed using Bland–Altman plots and intra-class correlation coefficients. A conversion algorithm between measurements was carried out using linear regression, and validated using bootstrapping and root-mean-square error. The agreement between VAMPIRE and IVAN was poor to moderate: The mean difference was 20.2 µm (95% limits of agreement, LOA, −12.2–52.6 µm) for CRAE and 21.0 µm (95% LOA, −17.5–59.5 µm) for CRVE. The agreement between VAMPIRE and SIVA was also poor to moderate: the mean difference was 36.6 µm (95% LOA, −12.8–60.4 µm) for CRAE, and 40.3 µm (95% LOA, 5.6–75.0 µm) for CRVE. The agreement between IVAN and SIVA was good to excellent: the mean difference was 16.4 µm (95% LOA, −4.25–37.0 µm) for CRAE, and 19.3 µm (95% LOA, 0.09–38.6 µm) for CRVE. We propose an algorithm converting IVAN and VAMPIRE measurements into SIVA-estimated measurements, which could be used to homogenize sets of vessel measurements obtained with different software packages

Evaluation of the time required to complete a cataract training program on EyeSi surgical simulator during the first-year residency

International audiencePurpose To evaluate the time required to complete a cataract training program for first-year ophthalmology residents using the EyeSi simulator. In addition, evaluate whether the simulator improves virtual performance of cataract surgery during the program. Methods We prospectively included first-year ophthalmology residents who had no experience of cataract surgery. The EyeSi simulator was used, and residents were able to follow the cataract training program, including course A (the easiest) through to course D (the hardest). In course B and above, a "cataract challenge" is proposed to the trainee every hour of simulation. Results A total of 24 participants were included in the study. During the study period, the mean (SD) total time spent on the surgical simulator was 815.6 (174.7) minutes. All the participants completed courses A and B within a mean (SD) of 366.7 (108.0) minutes. A total of 22 residents (91.7%) residents completed course C, and 5 (20.8%) course D. The mean (SD) best score on cataract challenge was 445.6/500 (40.2; range: 330-493) and was obtained in a mean (SD) 7.6 (2.6) attempts. All the residents obtained a score >= 60%. The best score in cataract challenge was not correlated to the time spent to achieve courses A and B (r = -0.37, p = 0.0726). Conclusions The time required to complete a basic cataract training program is possible during the first-year residency. The scores obtained in the cataract challenge also increased during the training program and should lead to better surgery skills in these young ophthalmologists

Evaluation of the time required to complete a cataract training program on EyeSi surgical simulator during the first-year residency

International audiencePurpose To evaluate the time required to complete a cataract training program for first-year ophthalmology residents using the EyeSi simulator. In addition, evaluate whether the simulator improves virtual performance of cataract surgery during the program. Methods We prospectively included first-year ophthalmology residents who had no experience of cataract surgery. The EyeSi simulator was used, and residents were able to follow the cataract training program, including course A (the easiest) through to course D (the hardest). In course B and above, a "cataract challenge" is proposed to the trainee every hour of simulation. Results A total of 24 participants were included in the study. During the study period, the mean (SD) total time spent on the surgical simulator was 815.6 (174.7) minutes. All the participants completed courses A and B within a mean (SD) of 366.7 (108.0) minutes. A total of 22 residents (91.7%) residents completed course C, and 5 (20.8%) course D. The mean (SD) best score on cataract challenge was 445.6/500 (40.2; range: 330-493) and was obtained in a mean (SD) 7.6 (2.6) attempts. All the residents obtained a score >= 60%. The best score in cataract challenge was not correlated to the time spent to achieve courses A and B (r = -0.37, p = 0.0726). Conclusions The time required to complete a basic cataract training program is possible during the first-year residency. The scores obtained in the cataract challenge also increased during the training program and should lead to better surgery skills in these young ophthalmologists

Retinal vessel phenotype in patients with a history of retinal vein occlusion

International audienceIntroduction: The aim of the study was to estimate the phenotypeof retinal vessels using CRAE (central retinal artery equivalent), CRVE (central retinal vein equivalent), tortuosity and fractal analysis in the unaffectedcontralateral eye of patients with central (CRVO) or branch (BRVO) retinal vein occlusion. Methods: 34patients suffering from CRVO, 15suffering from BRVOand 49 controlled-matched subjects had a fundus image analyzed using the VAMPIRE software. The intraclass correlation coefficient and a Bland-Altman plot were done for the reproducibility study.Results: There was a lack of evidence of differencebetween the control group and the CRVO group for CRAE (p=0.06), CRVE (p=0.3) and arterio-venule ratio(AVR, p=0.6).Contralateral eyes of CRVO exhibited a significantly higherarterial and minimum arterial tortuosity values (p=0.012), as compared with control eyes. Contralateral eyes of patients with ahistoryof BRVO had a significantly higherCRAE (p=0.02), AVR (p=0.006) and minimal arterial tortuosity (p=0.05). Fractal analysis showed that contralateral eyes of BRVO had higher values of fractal parameters(D0a, p=0.005).Conclusion: This study suggests that CVRO or BRVO are not triggered by the same retinal vascular phenotypes in the contralateral eye. The morphology of retinal vasculature may be associated with the occurrence of RVO, independentlyof known risk factors