Purpose: To investigate the morphological features of arteriovenous (AV) crossing in branch retinal vein occlusion (BRVO) using optical coherence tomography (OCT).
Subjects and methods: Using OCT, biplane projection focusing on BRVO was performed to investigate the AV crossing pattern, retinal vein compression at AV crossing, thrombi if present in the vein at AV crossing, and the thrombi site in 111 eyes in 111 consecutive cases of BRVO with AV crossing.
Results: The AV crossing pattern observed at the occluded site was arterial overcrossing ("AV crossing pattern") in 55 eyes (49.5%) and venous overcrossing ("VA crossing pattern") in 56 (50.5%). Compression of the vein at AV crossing was observed in nine eyes (8.1%), with all demonstrating VA patterns. Narrowing was observed between the internal limiting membrane and arterial wall at AV crossing. In 102 eyes (91.9%), the venous lumen was preserved despite curvature of the vein at AV crossing. Thrombi were detected in the vein at AV crossing in 15 eyes (13.5%), which comprised AV pattern in two of 55 eyes (3.6%) and VA pattern in 13 of 56 eyes (23.2%). The thrombi site was upstream of AV crossing in three eyes, at AV crossing in four, downstream of AV crossing in five, straddling AV crossing to its downstream in one, and straddling upstream of AV crossing to its downstream in two.
Conclusions: While it has conventionally been reported that most cases of BRVO involve the AV crossing pattern, we found that approximately half BRVO cases involved the VA crossing pattern. OCT is useful for observing the AV crossing morphology in BRVO cases.
Nippon Ganka Gakkai Zasshi (J Jpn Ophthalmol Soc) 122: 920-927, 2018.