We have read and reviewed the article entitled “The correlation of peripapillary and juxtapapillary choroidal thickness in healthy subjects” by Son et al. [1] with great interest. The authors investigated the peripapillary choroidal thickness (PPCT) and juxtapapillary choroidal thickness (JPCT) by using circle and radial B-scan images, respectively. The authors showed that the two measures of choroidal thickness (CT) around the optic nerve head were well correlated. However, the peripapillary choroid was generally thicker than the juxtapapillary choroid, especially in eyes with small Bruch’s membrane opening area. We congratulate the authors for their precious study, and we would like to request more details and their valuable contributions to the article.

The choroid is one of the most vascularized regions of the human body. Therefore, various local and systemic physiologic/pathologic conditions and environmental factors have effects on CT. It has been shown in the literature that age, sex, systemic or local diseases and their treatments, use of medicine, intraocular pressure, refractive error, axial length of the globe, and many other factors have effects on CT [2]. In addition, pregnancy, body mass index, menstrual cycle, and systemic blood pressure have a remarkable effect on CT. Furthermore, consuming food, and caffeinated or noncaffeinated drinks, and exercise before optical coherence tomography measurements can cause significant changes in CT [2]. Moreover, CT shows considerable diurnal variation and is able to increase by 50% in an hour and by four times in a few days [3]. We would like to ask authors whether all those factors have been assessed in the study.

We appreciate the comments of Drs. Salih Uzun and Fatma Uzun regarding our manuscript. As you mentioned, the choroid is one of the most vascularized regions of the human body and therefore, its volume is affected by various factors such as age, sex, systemic or local diseases and their treatments, use of medicine, intraocular pressure, refractive error, axial length of the globe, pregnancy, body mass index, menstrual cycle, and exercise. Due to the nature of this retrospective study, information such as the patient’s pregnancy status, body mass index, menstrual cycle, and amount of exercise could not be obtained. So, we could not show these matters in our study. Moreover, although CT shows considerable diurnal variation and is able to increase by 50% in an hour and by four times in a few days, the primary outcome of this study is to investigate the correlations of the PPCT and JPCT. So, both images were obtained within the few minutes, we think that the diurnal variation would be hard to affect our results.

We thank Drs. Salih Uzun and Fatma Uzun for their interest in our study.