Abstract
Purpose :
To analyze three-dimensionally the spectrum of vascular abnormalities in branch retinal vein occlusion (BRVO) using wide-field montage optical coherence tomography angiography (OCTA).
Methods :
We retrospectively reviewed 34 eyes of 34 consecutive patients with BRVO. En-face OCT angiograms (3 mm × 3 mm) of nine locations were acquired using the RTVue XR Avanti, and wide-field montage images of the superficial capillary plexus (SCP), deep capillary plexus (DCP), and radial peripapillary capillaries (RPC) were created. To assess the spectrum of abnormal vasculature, color fundus photography and fluorescein angiography were performed to identify retinal arterioles, venules, and occluded venules, which then were marked on the corresponding wide-field montage OCT angiograms. To evaluate the collateral vessels, the posterior pole region was divided into the nasal, foveal, and temporal areas. The different layers also were analyzed to detect the depth of the collateral vessels.
Results :
In all eyes, the boundary between the normal and abnormal vasculatures was concordant with the locations of the retinal arteries that were nearest to the occluded veins. In the 34 eyes, collateral vessels were detected in 28 (82%) eyes in the nasal area, 34 (100%) eyes in the foveal area, and 27 (79%) eyes in the temporal area. The depths of the vessels differed in each case; the collateral vessels were observed frequently in the SCP and RPC layers in the nasal area but only in the SCP and DCP layers in the temporal area.
Conclusions :
Wide-field montage OCTA visualizes vascular abnormalities not only around the fovea but also in the posterior pole. We propose that the affected area in BRVO is defined as the area between the occluded vein and arteries nearest to the occluded vein. The collateral vessels in BRVO may be more prevalent than previously reported and the collateral vessels run in a three-dimensional space across the retinal layers. Detail observations using wide-field montage OCTA can shed some light on the pathogenesis of BRVO.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.