Li Mengyang, Jin Enzhong, Dong Chongya, Zhang Chuan, Zhao Mingwei, Qu Jinfeng
Department of Ophthalmology, Peking University People's Hospital; Eye diseases and optometry Institute; Beijing Key Laboratory of Diagnosis and Therapy of Retinal and Choroid Diseases, College of Optometry, Peking University Health Science Center, Beijing, 100044, China.
Peking University First Hospital, Beijing, 100034, China.
BMC Ophthalmol. 2018 Dec 17;18(1):326. doi: 10.1186/s12886-018-0992-y.
To investigate the repeatability of superficial retinal vessel density measurements in healthy eyes with long axial length (AL) using optical coherence tomography angiography (OCTA).
There were 60 eyes of 31 volunteers enrolled in this cross-sectional observational study. All subjects underwent OCTA, AL and refraction test. The enrolled eyes were divided into the long AL group (26 mm ≤ AL < 28 mm) and normal AL group (22 mm ≤ AL < 26 mm). The vessel length density (VLD), perfusion density (PD), and fovea avascular zone (FAZ) of the superficial retinal vessel were evaluated. Repeatability was assessed by intraclass correlation coefficients (ICCs) and Bland-Altman analysis. Pearson's r correlation was used to analyze the relation of AL and the absolute difference between two measurements.
The 3 × 3 mm scan pattern showed good repeatability with all ICCs over 0.7. For all parameters of all scan patterns, the ICCs of the normal AL group were distinctly higher than those of the long AL group; this finding was also confirmed by Bland-Altman analysis. The correlation analysis of AL and repeatability of OCTA parameters showed significant negative correlations between the ALs and repeatability of VLD in 6 × 6 mm inner ring (r = 0.13, p = 0.01), VLD in 6 × 6 mm outer ring (r = 0.09, p = 0.02) and PD in 6 × 6 mm outer ring (r = 0.08, p = 0.03).
The AL and the scanned area will both affect the repeatability of superficial retinal vessel density measurements in OCTA.
使用光学相干断层扫描血管造影（OCTA）研究长眼轴（AL）健康眼中视网膜浅表血管密度测量的可重复性。
本横断面观察性研究纳入了31名志愿者的60只眼。所有受试者均接受了OCTA、眼轴长度测量和验光检查。纳入的眼睛被分为长眼轴组（26mm≤AL＜28mm）和正常眼轴组（22mm≤AL＜26mm）。评估视网膜浅表血管的血管长度密度（VLD）、灌注密度（PD）和黄斑无血管区（FAZ）。通过组内相关系数（ICC）和Bland-Altman分析评估可重复性。采用Pearson相关系数r分析眼轴长度与两次测量绝对差值之间的关系。
3×3mm扫描模式显示出良好的可重复性，所有ICC均超过0.7。对于所有扫描模式的所有参数，正常眼轴组的ICC明显高于长眼轴组；Bland-Altman分析也证实了这一发现。眼轴长度与OCTA参数可重复性的相关分析显示，眼轴长度与6×6mm内环的VLD可重复性（r = 0.13，p = 0.01）、6×6mm外环的VLD可重复性（r = 0.09，p = 0.02）以及6×6mm外环的PD可重复性（r = 0.08，p = 0.03）之间存在显著负相关。
眼轴长度和扫描区域均会影响OCTA中视网膜浅表血管密度测量的可重复性。
