Abstract
Purpose :
To quantify differences in retinal flow parameters between normal eyes and uveitic eyes with and without cystoid macular edema (CME) using swept-source optical coherence tomography (SSOCT)-based microangiography (OMAG).
Methods :
Subjects were recruited into 4 groups: 1) control eyes without uveitis (n=8), 2) uveitis without a history of CME (n=7), 3) uveitis with a history of CME, but not present at the time of the scan (n=7), and 4) uveitis with active CME at the time of the scan (n=10). Imaging was performed using CIRRUS SSOCT angiography provided by Zeiss Meditec Inc. Volume scans (3mmx3mm) were obtained at 1050nm, 100 kHz, and 100µm delta-λ providing 5µm axial and 14µm lateral resolution. Quantitative flow parameters including Vessel Diameter Index (VDI), Vessel Area Density (VAD), Vessel Skeleton Density (VSD), Vessel Complexity Index (VCI) and Vessel Perimeter Index (VPI) were calculated. Analysis was limited to a region of interest defined by a ring with inner diameter of 1mm and outer diameter of 3mm centered on the fovea. The 3 patient groups were compared by analysis of variance with post hoc t-test comparison and Bonferroni correction for multiple comparisons.
Results :
Significant differences between the groups were identified for all parameters except for VDI. Subsequent pair-wise comparisons demonstrated significant differences for VAD, VSD, and VPI after Bonferroni correction. There was a trend towards lower values of these three parameters for group3 vs control, group4 vs control, and group3 vs group2 (0.008<p<0.05). Group4 had significantly lower values of VAD, VSD, and VPI compared to group2 (p<0.008). There were no differences found between controls vs group2 or between group3 vs group4.
Conclusions :
Our findings suggest that structural changes occur in the perifoveal vasculature in the context of uveitic CME, particularly for parameters of vascular density. These changes are most pronounced in active CME, but still have detectable changes upon CME resolution. More pronounced differences between the disease and control eyes might be found in a larger, more heterogenous group of uveitic eyes. Hypotheses for our findings include measurement error, flow voids, or true vascular dropout/remodeling in the context of uveitic CME. Our SSOCT protocol shows promise for detecting past and present vascular density changes in uveitic CME.
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.