Dear Editor:

We read with great interest the article titled, "measurement and clinical implications of choroidal thickness in patients with inflammatory bowel disease". In their study, the authors investigated the relationship between inflammatory bowel diseases (IBD) and choroidal thickness (CT). Although CT was not found to be associated with IBD, the authors state high measurements as an indicator of ileal involvement in Crohn's disease. However, we have doubts regarding the accuracy of this hypothesis. IBD are well-known to be associated with anterior segment uveitis. If a cross-reaction between antigens against the ileal endothelium and choroid was present, a clinical presentation of uveitis would be expected, as in Vogt-Koyanagi-Harada syndrome. However, there was no report of such a presentation in their study.

In their study, decreased choroid thickness in patients with the Crohn's disease was found to be associated with colonic involvement. The mean CT in patients with ileal involvement was 324.7 with colonic involvement of 140.0. As ulcerative colitis (UC) is a disease of the colon, CT in patients with UC would be expected to be approximately 140 μm if the hypothesis of their study was correct. However, the mean CT in patients with UC was measured as approximately 300 μm, similar to measurements in patients with the Crohn's disease with ileal involvement. Therefore, we do not agree there could be an association between CT and ileal involvement. Further, as manual measurement of CT is not objective, we believe errors may have been introduced by incorrect measurements by the operators.