KHẢO SÁT HỆ VI MẠCH VÕNG MẠC VÙNG HOÀNG ĐIỂM TRÊN BỆNH NHÂN TẮC TĨNH MẠCH TRUNG TÂM VÕNG MẠC BẰNG OCT-A

Abstract

Purpose: To describe the morphological and quantitative characteristics of the foveal avascular zone (FAZ) and vessel density (VD) on optical coherence tomography angiography (OCT-A) in patients with central retinal vein occlusion (CRVO) after macular edema treatment. Subject and methods A cross-sectional descriptive study was conducted on 34 patients (34 affected eyes and 34 fellow eyes) diagnosed with CRVO and macular edema that had resolved following intravitreal anti-VEGF therapy at Ho Chi Minh City Eye Hospital. Patient screening and clinical examinations were performed to collect demographic and clinical data. FAZ parameters (area, perimeter, maximum diameter, circularity, axis ratio) and vessel density at the superficial and deep capillary plexuses were measured from 3×3 mm² OCT-A images acquired using the Cirrus HD-OCT 5000 system (Carl Zeiss Meditec, Dublin, USA). Results: On OCT-A, the most common findings were enlargement of non-perfusion areas (NPA), tortuous dilated capillaries, and disruption of the foveal avascular zone border. At the superficial capillary plexus (SCP), the mean FAZ area was 0,44 ± 0,22 mm², perimeter 2,69 ± 0,68 mm, maximum diameter 0,91 ± 0,24 mm, circularity 0,73 ± 0,10, axis ratio 1,30 ± 0,19, and vessel density 46,01% ± 5,76%. At the deep capillary plexus (DCP), the mean FAZ area was 0,81 ± 0,36 mm², perimeter 3,74 ± 0,83 mm, maximum diameter 1,17 ± 0,27 mm, circularity 0,70 ± 0,04, axis ratio 1,28 ± 0,12, and vessel density 39,43% ± 7,03%. All FAZ parameters and vessel density in both plexuses were significantly different from those of the fellow eyes (p < 0,05). Correlation analysis showed that FAZ area in SCP and DCP was positively correlated with logMAR visual acuity (SCP: r = 0,591; DCP: r = 0,758; p < 0,001), whereas vessel density was negatively correlated (SCP: r = –0,648; DCP: r = –0,694; p < 0.001). Conclusion: After treatment, CRVO eyes still demonstrated FAZ enlargement and reduced vessel density, particularly in both superficial and deep capillary plexuses. FAZ area and vessel density were significantly correlated with visual acuity, highlighting the potential role of OCT-A as a noninvasive tool for visual prognosis assessment after CRVO treatment.