雙眼視神經盤比例不等無視野缺損者之視網膜血管密度研究

Retinal Vessel Density in Subjects with Asymmetric Cup-to-Disc Ratio without Visual Field Defect

背景與目的：不對稱的視神經杯盤比被認為是疑似青光眼的特徵之一。光學相干斷層掃描血管造影可已非侵入性檢測視網膜微血管系統。這項研究旨在調查具不對稱視神經杯盤比者的血管密度特徵。 材料和方法：招募具有垂直不對稱視神經杯盤比≧0.2且無視野缺損的受試者。參加屈光檢查的患者納入正常組。所有參與者均接受了全面的眼科檢查和光學相干斷層掃描血管造影掃描。 結果：30名不對稱視神經杯盤比受試者和30名正常人參加了這項研究。在整個圖像（48.13％對50.05％； p = 0.007）和平均視神經週（51.58％對53.27％； p = 0.030）分析，具有較大視神經杯盤比的眼睛血管密度低於正常眼睛。區域分析顯示，在視神經週鼻上（47.23％對50.13％; p = 0.022），鼻下（45.66％對48.63％; p = 0.015）和下方區域（49.68％對52.63％； p = 0.026），具有視神經杯盤比大於正常眼的受試者眼血管密度較低。在視神經杯盤比大於正常眼的受試者眼，黃斑部上方象限也檢測到血流減少（46.35％對51.27％； p = 0.013）。在不對稱視神經杯盤比個體的兩隻眼睛之間，血管密度未發現差異。結論：在不對稱視神經杯盤比受試者中，兩隻眼睛的視神經週和黃斑部的視網膜微血管密度相似。與正常眼相比，具有較大視神經杯盤比的眼顯示出黃斑部上方象限及和視神經週血管密度減少。

Background and Purpose: Asymmetric cup-to-disc ratio (CDR) has been known as one of the features of possible glaucoma. Optical coherence tomography angiography (OCT-A) enables non-invasive detection retinal microvasculature. This study aims to investigate characteristics of vessel density (VD) in subjects with asymmetric CDR.

Materials and Methods: Subjects with asymmetric vertical CDR ≧0.2 without visual field deficit were recruited. Patients visiting for refraction checkup were enrolled in the normal group. All participants underwent comprehensive eye examinations and OCT-A scan.

Results: Thirty subjects with asymmetric CDR and 30 normal individuals participated in this study. Eyes with larger CDR had lower peripapillary VD than normal eyes at whole image (48.13% vs. 50.05%; p = 0.007) and average peripapillary (51.58% vs. 53.27%; p = 0.030). Regional analysis showed that there was a reduction of VD in eyes with larger CDR than in normal eyes at nasosuperior (47.23% vs. 50.13%; p = 0.022), nasoinferior (45.66% vs. 48.63%; p = 0.015), and inferior sectors (49.68% vs. 52.63%; p = 0.026). Flow impairment was also detected at the superior quadrant of macula in eyes with larger CDR than in normal eyes (46.35% vs. 51.27%; p = 0.013). No difference in VD was found between two eyes of individuals with asymmetric CDR. Conclusions: Among subjects with asymmetric CDR, retinal microvasculature at the optic nerve head and at macula were similar in both eyes. Eyes with larger CDR showed reduction of peripapillary and superior quadrant of parafoveal VD in comparison with normal eyes.