Session Title: Imaging III
Session Date/Time: Saturday 19/09/2015 | 16:30-18:00
Paper Time: 16:54
First Author: : I.Sobral PORTUGAL
Co Author(s): : C. Fonseca A. Baltar M. Seara M. Soares M. Cachulo R. Silva
PURPOSE:The purpose of this study is to evaluate clinical findings and morphologic features of branch retinal vein occlusion (BRVO) using Optical Coherence Tomography-Angiography (Angio-OCT).
Ophthalmology Department, Centro Hospitalar e Universitário de Coimbra, Coimbra, Portugal; Association for Innovation and Biomedical Research on Light (AIBILI), Coimbra, Portugal; Faculty of Medicine, University of Coimbra, Coimbra, Portugal.
Retrospective observational nonrandomized study with a cross-sectional evaluation, that included 20 eyes of 20 patients diagnosed with BRVO, who underwent treatment with intravitreal ranibizumab (IR), with or without laser photocoagulation (LP). Patients with a minimum follow-up of 2 years were included. History of central retinal vein occlusion and/or other visual comorbidities were considered as exclusion criteria. All subjects were called to return to ophthalmologic evaluation and perform Angio-OCT (3.00 x 3.00 scan size). Structural alterations at the superficial and deep vascular retinal networks were described including: vascular tortuosity, areas of ischemia, foveal ring (FR) rupture and collateral circulation. The foveal avascular zone (FAZ) area of the superficial and deep plexus was calculated using the ImageJ software and a double-blind method with two observers was used to measure the areas. We compared baseline and final visual acuities (VA) in the affected eye (Wilcoxon signed rank test). We also investigated the association between superficial FR rupture and final VA, collateral circulation and final VA, superficial FAZ areas in the affected eye and non-affected eye (Wilcoxon rank sum test) and association between baseline and final VA and superficial FAZ areas (Spearman correlation).
Our population had a mean age of 64.2±11.1 years, 55% were female. The mean number of IR was 12.7±6.2 and 9 patients underwent LP. Baseline and final VA were 53.5±17.3 and 70.4±16.1 letters respectively, representing a s tatistical significant improvement (z=-3.961; p less than 0.001). All images showed changes in both superficial and deep plexus. In the area of the affected venous branch, these plexus were consistently dilated and tortuous; such findings more notorious in the deep network. Ischemia was a common feature present in all patients, appearing as abrupt interruptions and rarefaction/absence of the capillaries. In 35% of the affected eyes, ischemia reached the superficial FAZ causing FR rupture, without significant association with final VA (z=-0.318; p=0.7504). There was no association between initial (r=-0.21; p=0.38) and final (r=-0.21; p=0.38) VA, and the superficial FAZ area. This area did not reveal significant differences between the affected and the non-affected eyes (z=1.026; p=0.305). In the deep plexus, ischemia was so remarkable that interfered with FAZ measurements in 60% of cases. Superficial and deep collateral circulation was observed in 55% of patients, without association with final VA (z=1.067; p=0.2859).
The Angio-OCT is an innovative noninvasive diagnostic test that allows better understanding of the effects of BRVO in both superficial and deep vascular networks, the latter being an remarkable novelty in retinal vascular imaging. In patients with BRVO, superficial and deep vascular network changes were documented, such as ischemic areas, presence of vascular tortuosity, development of collateral circulation, rarefaction of vascular texture and changes in the shape of the vascular ring near the avascular fovea. The deep network was more affected than superficial plexus, with pronounced ischemia and collateral circulation. It is currently difficult to find an association between the referred changes and final visual acuity, since the scans were qualitatively interpreted and show a large interindividual variability. Moreover, as this is a recent technology, interpretation of the obtained scans needs further learning and standardization.