Application Of Quantitative OCTA In Retinal Vein Occlusion

Objectives:To investigate the changes of macular perfusion in retinal vein occlusion using optical coherence tomography angiography and the correlation with visual acuity.Methods:Retrospective study.30 patients with unilateral RVO were enrolled.OCTA was performed on the RVO and fellow eyes.Macular vascular density,FAZ area,foveal thickness and visual acuity were measured in all eyes.The changes of vascular density,FAZ area,foveal thickness and its correlation with visual acuity were compared between the eyes and the fellow eyes.Results:Fifteen patients with CRVO and fifteen patients with BRVO met inclusion criteria.In eyes with CRVO the overall vascular density measured in the entire scan was lower compared to fellow eyes in both the superficial(43.07±4.95%vs 50.0±2.86%,respectively;P<0.01)and deep(45.89±4.12%vs 53.29±2.62%,respectively;P<0.01)networks.And a positive correlation was found between the visual acuity and the overall density in superficial(r = 0.6,P = 0.01)and deep(r = 0.5,P = 0.04)networks.In eyes with BRVO the overall vascular density measured in the entire scan was lower compared to fellow eyes in both the superficial(45.6±3.04%vs 52.10±2.98%,respectively;P<.001)and deep(49.21±3.80%vs 55.52±3.33%,respectively;P<0.01)networks.And a positive correlation was found between the visual acuity and the overall density in superficial(r = 0.5,P=0.02)and deep(r = 0.6,P = 0.01)networks.In both networks,the density was lower in the affected BRVO sector compared to the unaffected sector in the same eye and in the fellow eye(P<0.01).And the vascular density in the affected BRVO sector correlated positively with visual acuity in the deep network(r=0.4,P=0.04).In the deep network,the density was lower in the unaffected sector of the BRVO eye compared with the corresponding sector in the fellow eye(56.86±1.95 vs 58.15±2.24,respectively;P=0.02).The mean FAZ area in CRVO and BRVO eyes was significantly lower at the superficial network when compared to the fellow eyes(CRVO:0.515±0.26mm2 vs 0.27±0.08mm2,P<0.01;BRVO:0.376±0.12mm2 vs 0.261±0.07mm2,P<0.01)and correlated negatively with visual acuity(CRVO:r=-0.6,P = 0.02;BRVO:r=-0.5,P = 0.01).The mean foveal thickness in CRVO and BRVO eyes was significantly thicker when compared to the fellow eyes(CRVO:431.2±191.3mm vs 235.5±18.2mm,P<0.01;BRVO:373.2±188.7mm vs 243.8±13.7mm,P=0.01)and correlated negatively with visual acuity(CRVO:r =-0.7,P<0.01;BRVO:r =-0.6,P = 0.01).Conclusion:Quantitative OCTA can be used as an effective tool for measuring blood flow in macular areas and FAZ area of RVO patients.In eyes with RVO the overall vascular density measured was lower compared to fellow eyes in both the superficial and deep networks,and appear to correlate with visual acuity.Moreover,FAZ area expansion in superficial network and foveal thickness increase appear to correlate with visual acuity.