Differences In Foveal Avascular Zone Area Research Articles

Quantitative Comparison Of Microvascular Metrics On Three Optical Coherence Tomography Angiography Devices In Chorioretinal Disease.

PurposeOptical coherence tomography angiography (OCT-A) has emerged as a novel tool for the non-invasive imaging and evaluation of the retinal microvasculature. There is little existing literature that compares OCT-A microvasculature metrics across different OCT-A devices in chorioretinal diseases. Herein, we examined these metrics on three available OCT-A platforms.Patients and methodsAll subjects were scanned on each of three OCT-A devices: Optovue Avanti Angiovue, Topcon DRI-OCT Triton Swept-Source OCT, and Zeiss Cirrus 5000-HD-OCT Angioplex. Two investigators independently measured foveal avascular zone (FAZ) area. Superficial capillary plexus (SCP) and deep capillary plexus (DCP) vessel densities (VD) were calculated from binarized images with ImageJ software. Image quality across devices was qualitatively compared. Interclass correlation coefficient (ICC), Bland-Altman analysis, repeated measures ANOVA, and post-hoc tests were performed for statistical analysis.ResultsThirteen eyes of seven patients with chorioretinal diagnoses were reviewed. ICC for FAZ measurement was 0.95. There was no significant difference in FAZ area across the three devices (p= 0.792). There was a significant difference in the SCP VD between the OCT-A devices (Triton 0.344 ± 0.013, Angiovue 0.323 ± 0.013, Angioplex 0.367 ± 0.014, p < 0.05). Significantly greater DCP VD was observed with Angioplex (0.385 ± 0.010) in comparison to both Triton (0.331 ± 0.009) and Angiovue (0.341 ± 0.020). A comparison of image quality revealed that Angiovue gives the highest quality, followed by Angioplex and Triton.ConclusionCore macular microvasculature metrics are now readily accessible on a variety of available OCT-A devices. While the FAZ can be reliably measured across all three devices in this study, there were significant differences for the vessel density in both the SCP and DCP. As a result, clinicians should be careful when comparing microvasculature metrics across different devices when using patient data in multicenter research investigations and clinical trials.

ACUTE EFFECT OF CAFFEINE ON MACULAR MICROCIRCULATION IN HEALTHY SUBJECTS: An Optical Coherence Tomography Angiography Study.

To evaluate the acute effects of caffeine on macular microvasculature using quantitative optical coherence tomography angiography analysis. Fifty-two healthy subjects aged 24 to 48 years were randomly divided into 2 groups: a control group, which received placebo, and a study group, which was subjected to caffeine. All participants underwent optical coherence tomography angiography at baseline and 1 hour after 200-mg oral caffeine intake in the study group and after oral placebo in the control group. Macular flow area, macular vessel density, and foveal avascular zone (FAZ) area were analyzed in both the groups. The study group consisted of 14 men and 12 women with a mean age of 40.6 ± 8.9 years. The mean age of control group was 39.5 ± 9.4 years, which consisted of 13 men and 13 women. Baseline macular flow area, vessel density, and FAZ area measurements of the study and control groups showed no significant difference (P > 0.05). Oral caffeine intake caused a significant reduction in macular flow area (superficial, deep, and choriocapillaris) and vessel density (P < 0.05). However, there was no statistically significant difference in FAZ area after caffeine intake when compared with baseline measurements (P = 0.063). We found a significant decrease in macular flow area (superficial, deep, and choriocapillaris) and vessel density after caffeine intake. Our findings are consistent with previous studies using other techniques. We believe that the results of this preliminary study will be useful in future studies about this topic.

Parafoveal Retinal Vessel Density Assessment by Optical Coherence Tomography Angiography in Healthy Eyes

To assess variability in vessel density (VD) measurements across three optical coherence tomography angiography (OCTA) devices to identify a methodology that offers the least amount of variation in VD, and to assess the effect of averaging of multiple scans on VD variability. Fifteen eyes of eight healthy individuals were imaged consecutively on three OCTA devices. Segmentations at the superficial, deep, and full retinal layers were generated. Repeat scans for each retinal layer were registered and averaged to generate one OCTA image. Two different automated thresholding techniques were used to calculate vessel area density (VAD) from binarized images and vessel skeleton density (VSD) from skeletonized images. Vessel length, a linear measure of the combined lengths of vessels, was calculated. Foveal avascular zone (FAZ) area was measured. All three OCTA devices were significantly different (P < .0001). This finding remained after averaging images (P < .0001). VSD was more repeatable within a device but less reproducible across devices. Conversely, VAD demonstrated less repeatability but greater reproducibility. Differences in VSD between devices were systematic and attributable to differences in resolution. Vessel length, unaffected by resolution, demonstrated no significant differences between the devices (P > .107). There was no significant difference in FAZ area across devices (P = .51). After averaging images, VD was significantly different from the single images for each device and plexus (P < .05) but remained within 1% of the value of a single scan. OCTA devices show variability in VD for healthy individuals. With greater repeatability, VSD appeared useful for following a patient on one device. VAD and vessel length seemed ideal for comparing vessel parameters between OCTA devices. After averaging multiple scans, VSD remained within 1% of a single scan, for which clinical significance remains to be determined. Caution is advised when comparing quantitative analyses across OCTA devices. [Ophthalmic Surg Lasers Imaging Retina. 2018;49:S5-S17.].