Non-perfusion severity correlates with central macular thickness and microvascular impairment in branch retinal vein occlusions

Detection of Retinal and Choriocapillaris Microvascular Changes in Retinal Vein Occlusion and Fellow Eyes by Optical Coherence Tomography Angiography: A Systematic Review and Meta-Analysis

INTRODUCTION

This study aims to summarize the retinal and choroidal microvascular features detected by optical coherence tomography angiography (OCTA) in the affected and fellow eyes of patients with retinal vein occlusion (RVO).

METHODS

A comprehensive search of the PubMed, Embase, and Ovid databases was conducted to identify studies comparing OCTA metrics among RVO, RVO-fellow, and control eyes. Outcomes of interest included parameters related to foveal avascular zone (FAZ) and fovea- and optic nerve head (ONH)-centered perfusion measurements of superficial capillary plexus (SCP), deep capillary plexus (DCP), and choriocapillaris layer. Pooled results were presented as mean differences or standardized mean differences with 95% confidence intervals.

RESULTS

Fifty-three studies, comprising 2119 RVO, 1393 fellow, and 1178 control eyes, were included in the quantitative meta-analysis. RVO eyes exhibited larger FAZ areas, increased FAZ acircularity, and reduced macular retinal and choriocapillaris perfusion compared to RVO-fellow and control eyes (P < 0.05). RVO eyes also demonstrated significantly lower perfusion density (PD) in the inside-disk and peripapillary regions of the radial peripapillary capillary layer (RPC), as well as lower retinal and choriocapillaris PD in the 4.5 × 4.5 mm2 field of view (FOV) of ONH-centered scans (P < 0.05). RVO-fellow eyes showed decreased SCP-PD and DCP-PD in the parafoveal region and the 3 × 3 mm2 FOV, reduced inside-disk and 4.5 × 4.5 mm2 FOV RPC-PD (P < 0.05), and a diminished choriocapillaris flow area in the 3 × 3 mm2 FOV (P < 0.05).

CONCLUSIONS

Both RVO-affected and RVO-fellow eyes exhibited retinal and choriocapillaris microvascular impairment around the fovea and ONH. OCTA represents a promising tool for comprehensively assessing vascular alterations in RVO and providing evidence of fellow eye involvement.

Evaluation of Anatomical and Tomographic Biomarkers as Predictive Visual Acuity Factors in Eyes with Retinal Vein Occlusion Treated with Dexamethasone Implant

Background: This prospective study evaluated the impact of anatomical and tomographic biomarkers on clinical outcomes of intravitreal dexamethasone implants in patients with macular edema secondary to retinal vein occlusion (RVO). Methods: The study included 46 patients (28 with branch RVO (BRVO) and 18 with central RVO (CRVO)). Best corrected visual acuity (BCVA) significantly improved from a mean baseline of 0.817 ± 0.220 logMAR to 0.663 ± 0.267 logMAR at six months and 0.639 ± 0.321 logMAR at twelve months (p < 0.05). Central retinal thickness (CRT) showed a significant reduction from 666.2 ± 212.2 µm to 471.1 ± 215.6 µm at six months and 467 ± 175.7 µm at twelve months (p < 0.05). No significant differences were found in OCT biomarkers between baseline and follow-ups. Results: The study analysed improvements in visual acuity relative to baseline biomarkers. At six months, ellipsoid zone disruption (EZD) was significant for all subgroups. Disorganization of retinal inner layers (DRIL), external limiting membrane (ELM) disruption, macular ischemia (MI), CRT, and BRVO showed significance for any improvement, while DRIL and ELM were significant for changes greater than 0.3 logMAR (p < 0.05). At twelve months, EZD remained significant for all subgroups. ELM, MI, CRT, and BRVO were significant for any improvement, while MI and BRVO were significant for changes greater than 0.3 logMAR (p < 0.05). Hyperreflective foci were not statistically significant at either time point (p > 0.05). Conclusions: The regression model suggested that MI and CRVO could be negative predictive factors for visual outcomes, while ELM and EZD were associated with BCVA improvement one-year post-treatment.

RELATIONSHIP BETWEEN RETINAL HEMORRHAGE ON GREEN AND RED CHANNELS OF ULTRA-WIDEFIELD FUNDUS IMAGES AND RETINAL PERFUSION IN ACUTE BRANCH RETINAL VEIN OCCLUSION

PURPOSE

To explore the relationship between retinal hemorrhage in the green and red channels on ultra-widefield fundus images and the nonperfusion area (NPA) on ultra-widefield fundus fluorescein angiography in patients with acute branch retinal vein occlusion (BRVO).

METHODS

This was a retrospective cross-sectional study with 96 patients, including 46 with ischemic BRVO and 50 with nonischemic BRVO. Correlation analysis between green channel hemorrhage (GCH), red channel hemorrhage (RCH), and NPA was performed. Panretina was divided into posterior and peripheral areas.

RESULTS

Ischemic BRVO showed significantly higher GCH% and RCH% than nonischemic BRVO in the peripheral regions (both P < 0.001), whereas no significant differences were observed in the panretinal and posterior areas (all P > 0.05). Significant correlations were found between NPA% in the panretinal and peripheral areas and the corresponding GCH% and RCH% (all P < 0.01). However, no significant correlation was observed between posterior NPA% and posterior GCH% or RCH% (both P > 0.05). In addition, peripheral GCH% and RCH% were related to panretinal NPA% (r = 0.506, P < 0.001; r = 0.558, P < 0.001).

CONCLUSION

Retinal hemorrhage on ultra-widefield fundus image was significantly associated with NPA, providing insights for assessing retinal perfusion status in acute BRVO patients.

Relationship between ischemic index, leakage index, and macular edema in branch retinal vein occlusion

PURPOSE

To investigate the combined association of the ischemic index and leakage index with macular edema on ultra-widefield fluorescein angiography (UWFFA) in patients with branch retinal vein occlusion (BRVO).

METHODS

Retrospective image analysis study. The leakage index and ischemic index were calculated using Fiji after aligning early and late UWFFA images. Differences in the ischemic index, leakage index, and central macular thickness (CMT) between ischemic and non-ischemic BRVO were compared. Moreover, the association between the ischemic index, leakage index, and macular edema was analyzed.

RESULTS

Eighty-three patients with BRVO were enrolled, including 53 non-ischemic BRVO and 30 ischemic BRVO patients. No significant differences were observed in leakage index and CMT between ischemic BRVO and non-ischemic BRVO (all P > 0.05). In all included patients, CMT correlated with the panretina and all subregion leakage indexes (all P < 0.01), but not with the ischemic index (all P > 0.05). In the ischemic BRVO group, CMT showed a correlation with the leakage index in several regions, but not with the ischemic index. After adjusting for the ischemic index and other clinical features, CMT remained significantly correlated with the leakage index in all regions.

CONCLUSION

The leakage index may be a more effective biomarker for monitoring BRVO-associated macular edema compared to the ischemic index. Further follow-up studies are warranted to validate these findings.