LAUSR

Editor, W e thank the authors for their valuable comments. Since a well-defined choroid–scleral interface (CSI) or junction (CSJ) is a principal landmark for quantifying the choroid on EDI-OCT, accurate determination of the CSI is therefore critical for consistency in choroidal measures. We acknowledge the study by Yiu and colleagues (2014) reporting the presence of a hyporeflective band corresponding to the suprachoroidal layer (SCL) and the three different posterior boundaries: posterior large-vessel border, inner border of the SCL and inner border of the sclera. They found that SCL was visible in 45% of the study eyes. Similar to other published papers (Spaide et al. 2008), we measured choroidal thickness between outer border of the retinal pigmented epithelium and inner border of the sclera (Gupta et al. 2016). As Moisseiev et al. (2015) pointed out, in subjects with visible SCL, the term CSI may mean the interface between choroid stroma and SCL. However, we cannot distinguish SCL clearly in our cohort, and visibility of CSI was thus defined as the clearly identifiable border between the large-vessel layer of the choroid and the sclera in our study. The visibility of the SCL is much lower than that of the CSI (10% versus 60%). The discrepancy of SCL visibility between Yiu et al. (2014) study and our study is unclear, but may be due to increased pigmentation in Asians and younger age group in our cohort. Further studies are warranted to clarify. The definition of posterior choroidal boundary (inner border of sclera versus SCL) might potentially result in inconsistency in choroidal thickness measurements across the studies. We again echo Moisseiev et al.’s (2015) point of view that consistency in CSI definition and objective method for the measurement are essential for an accurate choroidal thickness measurement.