Changes in Macular Microvascular Structure in Macular Edema Secondary to Branch Retinal Vein Occlusion Treated with Antivascular Endothelial Growth Factor for One Year

Abstract

Purpose. To observe the changes in macular microvascular structure and the correlation between anatomy and visual function in patients with macular edema secondary to branch retinal vein occlusion (BRVO) treated with antivascular endothelial growth factor for one year. Methods. This prospective study enrolled 39 patients (one eye per patient) who received intravitreal injections of ranibizumab for macular edema secondary to BRVO. All patients received a minimum of 3 initial monthly ranibizumab injections and criteria-driven pro re nata (PRN) dosing thereafter for visual acuity (VA) and central retinal thickness (CRT) stabilization. The follow-up period of this study was one year. The vascular density (VD) of the superficial retinal capillary plexus (SCP) and deep retinal capillary plexus (DCP), the foveal avascular zone (FAZ) area, the FAZ perimeter, the VD within a 300 μm wide ring surrounding the FAZ (FD-300), and the acircularity index (AI) were measured automatically by optical coherence tomography angiography (OCTA) at baseline, month 6, and month 12. Results. Compared with those before treatment, the VD of the SCP significantly decreased 6 months after treatment ( P < 0.05 ), while the area and perimeter of the FAZ increased significantly ( P < 0.01 ). After 12 months of treatment, the area and perimeter of the FAZ increased significantly ( P < 0.01 ). There was no significant difference in any parameters between 12 months and 6 months after treatment ( P > 0.05 ). The change in BCVA was negatively correlated with the VD of the SCP at 12 months ( P = 0.0447 , r = −0.3233). There was a relationship between the DBP and AI, and CRT was related to VD of DCP at baseline ( P = 0.028 , 0.0209 ; r = 0.383, −0.384). The PERIM and AI at 12 months were significantly associated with the recurrence of macular edema, and the changes in vascular density in the SCP and PERIM were significantly associated with the number of injections within 12 months ( P < 0.05 ). Conclusions. One year after ranibizumab treatment, the area and perimeter of the FAZ were enlarged, while the VD of the SCP and DCP remained stable, which indicated that ranibizumab treatment did not improve macular blood supply and macular ischemia in BRVO patients.

Wide-field swept-source OCT angiography of the periarterial capillary-free zone before and after anti-VEGF therapy for branch retinal vein occlusion

“…Song et al found that there was no significant correlation between FAZ and visual acuity in BRVO before and after anti-VEGF therapy [ 32 ], which was consistent with the results of our studies. These discrepancies may be related to the interindividual variability in the FAZ size [ 15 ], various measurement methods [ 30 , 31 ], OCTA instrument [ 32 ], and different stages of BRVO in which the acute macular edema with masked or displaced macular vessels may affect the accurate measurement of FAZ [ 31 ]. In this study, the paCFZ parameters were measured along the major retinal arteries and less affected by the macular edema or hemorrhage, which might be an advantage of the paCFZ biomarker.…”

“…Wakabayashi et al reported that a smaller FAZ area was associated with better visual acuity after treatment of macular edema in BRVO, but it was not a significant variable in the multivariate linear regression model [ 31 ]. Song et al found that there was no significant correlation between FAZ and visual acuity in BRVO before and after anti-VEGF therapy [ 32 ], which was consistent with the results of our studies. These discrepancies may be related to the interindividual variability in the FAZ size [ 15 ], various measurement methods [ 30 , 31 ], OCTA instrument [ 32 ], and different stages of BRVO in which the acute macular edema with masked or displaced macular vessels may affect the accurate measurement of FAZ [ 31 ].…”

“…However, there was no significant correlation between baseline FAZ and BCVA at 12 months. A few studies have previously reported a correlation between visual acuity and FAZ, but the conclusions have been inconsistent [ 8 , 30 – 32 ]. Some studies have found that enlargement of the FAZ was associated with reduced visual acuity [ 8 , 30 ].…”

Structural and Visual Changes in Branch Retinal Vein Occlusion Patients with Retinal Atrophy

“…FAZ area, FAZ perimeter, FAZ AI, FD-300-VD, foveal SVC-VD, and foveal DVC-VD were often considered indexes of macular ischemia [ 29 ]. We found that only FD-300-VD in atrophy eyes significantly decreased compared with nonatrophy eyes.…”

Predicting OCT images of short-term response to anti-VEGF treatment for retinal vein occlusion using generative adversarial network

“…Optical coherence tomography (OCT) is widely acknowledged as a high-resolution imaging modality for quantifying retinal thickening and fluid accumulation in patients with RVO and assessing the severity of macular edema. Accordingly, OCT is the primary tool for the examination and follow-up of RVO-related macular edema cases ( Kashani et al, 2017 ; Song et al, 2021 ).…”