Objective o compare the differences in the choroidal thickness at 1500 μm nasal or temporal to the fovea between three measurements of different imaging modes. Methods In this retrospective study, 21 eyes from 20 patients diagnosed with central serous chorioretinopathy (CSC), whose retinas tilt over 5.0 degree to the horizontal line were included (retina tilt group). The control group (retinal horizontal group) also included 21 eyes from 20 individuals whose retinas are horizontal indicated by retinal tilt angle measurement. There were no statistical significance (t=0.00, -0.345, 0.489; P＞0.05) in gender, age and spherical equivalent distributions between the two groups. The choroidal thickness at 1500 μm nasal or temporal to the fovea was measured by spectral-domain optical coherence tomography (COT) enhanced depth scanning under three modes (1∶1 pixel, 1∶1 micron and continuous measurement). The differences of choroidal thickness between these three measure modes were analyzed by a paired t test. Results The choroidal thickness was (304.81±87.74), (342.86±91.43), (307.86±89.35) μm respectively measured by 1∶1 pixel, 1∶1 micron and continuous measurement modes in retinal tilt group. The choroidal thickness measured by 1∶1 pixel was increased compare to that by 1∶1 micron, the difference was statistically significant (t=-8.499, P＜0.01). The choroidal thickness measured by continuous measurement mode was the same of that by 1∶1 micron, the difference was not statistically significant (t=-0.790, P＞0.05). In retinal horizontal group, the choroidal thickness measured by these 3 modes was the same, the difference was not statistically significant (t=-1.521, -1.822; P＞0.05). Conclusions Spectralis OCT with 1∶1 pixel mode exhibits horizontally compressed image, the values of choroidal thickness under tilted retinas measured by this condition were significantly greater than the true ones. The choroidal thickness measured by 1∶1 micron mode measurement is more accurate. Continuous measurement mode provides more accurate and convenient choroidal thickness measurement during follow up of patients.
Citation： 曲鹏,罗文,李岩,郑薇薇,孙祖华,刘晓玲. The differences of the choroidal thickness measured by spectral-domain optical coherence tomography in three kinds of imaging modes. Chinese Journal of Ocular Fundus Diseases, 2013, 29(5): 453-456. doi: Copy