In the present study, the linear artifact was stably located at 485 μm from the outer border of the RPE hyper-reflective band in normal subjects and in subjects with many ocular diseases in which the SFCT is an important reference parameter. While the average SFCT in our study was 325.43 ± 140.98 μm, the actual sclerochoroidal interface could be located above, below or at the same level as the linear artifact. Because the location of the linear artifact line was stable, the different relative positions mainly depended on differing SFCTs. When SFCT was thin, the sclerochoroidal interface was located above the linear artifact, and the artifact had little influence over the measurement of SFCT. However, when SFCT was thick, the sclerochoroidal interface was located at the same level of the linear artifact, and interfered with the measurement of SFCT. When SFCT was thicker, the sclerochoroidal interface was located below the linear artifact. Therefore, the artifact is most likely to be mistaken for the sclerochoroidal interface in the absence of careful observation or a clear image, especially in eyes with a thickened choroid, such as in APACG, PACS, CPACG and CSC. The rate of sclerochoroidal interface below and at the same level as the linear artifact line was upto 20.1% in patients with increased SFCT. The results of this study show that the linear artifact is a confounding factor in assessing the thickness of the choroid, especially in patients with increased SFCT.