Purpose
To assess the retinal vasculature in patients with retinal vein occlusion (RVO) using OCTA.
Methods
Cross-sectional, observational study of subjects with RVO. All subjects underwent complete ophthalmic examination and had a confirmed diagnosis of RVO. Data was acquired using a Cirrus high-speed 1050 nm SS-OCT prototype system (100,000 kHz) and a 840 nm SD-OCT prototype system (67,500 kHz)(Carl Zeiss Meditec, Dublin, CA) on 3x3mm sections of the macula and compared to conventional fluorescein angiography (FA). Retinal vasculature was assessed in three retinal slabs consisting of the superficial retina (inner limiting membrane to superficial inner plexiform layer), middle retina (deep inner plexiform layer to superficial outer nuclear layer) and outer retina (deep outer nuclear layer to external limiting membrane). The vasculature was reconstructed using a phase and intensity contrast based algorithm and visualized en face for comparison with fluorescein angiograms (FA). <br /> <br />
Results
OCTA in subjects with RVO (N=5) clearly demonstrates areas of non-perfusion, tortuous or dilated vessels and abnormal capillary morphology. These findings are qualitatively consistent with findings on fluorescein angiography (FA). Dilated and anomalous capillaries were more clearly defined in OCTA than in most frames of fluorescein angiograms. This is particularly evident in late FA images with even mild leakage that tended to washout surrounding capillaries. There were no findings on OCTA that correlated with areas of FA leakage in any case. OCTA demonstrated clear areas of capillary non-perfusion that correlated well with FA findings. Using OCTA, the capillary non-perfusion could be localized to both inner and middle retinal layers in all cases.
Conclusions
OCTA provides high-resolution and non-invasive angiograms that correlate well with most findings on fluorescein angiography, except dye leakage. OCTA shows that capillary non-perfusion in RVO involves both inner and middle retinal layers.