Kim Kyoung Nam, Shin Il Hwan, Sung Jae Yun, Kwak Baek Soo, Lim Hyung Bin, Jo Young Joon, Kim Jung Yeul
Department of Ophthalmology, Chungnam National University College of Medicine, Daejeon, Republic of Korea.
Department of Computer Engineering, San Jose State University, San Jose, CA, USA.
Graefes Arch Clin Exp Ophthalmol. 2017 Jun;255(6):1107-1113. doi: 10.1007/s00417-017-3615-z. Epub 2017 Mar 6.
To evaluate the effect of spectral domain-optical coherence tomography (SD-OCT) measurement center shift on the measurement of macular thickness.
This was a prospective observational case series. A total of 60 normal eyes of 60 subjects included in the study. SD-OCT macular scanning (macular cube 512 × 128 scan) was performed twice by an experienced examiner. The average retinal thicknesses of the nine macular sectors as defined by the Early Treatment Diabetic Retinopathy Study (ETDRS) were recorded. Each coefficient of repeatability was calculated for the macular thickness measurements of the ETDRS subfields. Thereafter, the measurement center was manually decentered to a seven scan point, each from the central fovea in steps of 58.7 μm horizontally and 47.2 μm vertically. At each shift point, the change in the macular thickness was compared.
When the displacement distance between the measurement center point and the foveal center was within 117.4 μm horizontally and 141.6 μm vertically, the macular thickness measurements did not show any significant differences. However, if the offset of the EDTRS grid center from the anatomic fovea exceeded, we noted that the thickness at the fovea increased and the opposite-direction region at the inner circle was significantly thinner than the displaced point.
The effect of measurement center shift needs to be considered when analyzing the macular thickness measurements in various ophthalmologic diseases.
评估频域光学相干断层扫描（SD - OCT）测量中心偏移对黄斑厚度测量的影响。
这是一个前瞻性观察性病例系列研究。共纳入60名受试者的60只正常眼。由一名经验丰富的检查者对黄斑进行两次SD - OCT扫描（黄斑立方体512×128扫描）。记录早期糖尿病性视网膜病变研究（ETDRS）所定义的九个黄斑区域的平均视网膜厚度。计算ETDRS子区域黄斑厚度测量的每个重复性系数。此后，将测量中心手动偏离至距中央凹七个扫描点处，水平方向每次偏离58.7μm，垂直方向每次偏离47.2μm。在每个偏移点，比较黄斑厚度的变化。
当测量中心点与黄斑中心的水平位移距离在117.4μm以内且垂直位移距离在141.6μm以内时，黄斑厚度测量未显示出任何显著差异。然而，如果EDTRS网格中心相对于解剖学黄斑中心的偏移超过上述范围，我们注意到黄斑处的厚度增加，且内圈相反方向区域明显比偏移点处更薄。
在分析各种眼科疾病的黄斑厚度测量结果时，需要考虑测量中心偏移的影响。
