Reply to letter to editor

Dear Editor,

We would like to thank Dr D’Aniello and her colleagues for raising their concerns. We read their comments on the manuscript with great interest, and we appreciated their valuable contribution.

As stated in the letter, the choroidal vascularity index (CVI) is a hot topic in ophthalmology, and numerous reports have been published so far regarding CVI and its potential applications in healthy eyes and chorioretinal diseases. Sonoda et al. firstly described the technique to evaluate subfoveal luminal and stromal area by an image binarization process of EDI spectral-domain optical coherence tomography (OCT) scan. ¹ Several modifications have been further proposed by Agrawal et al. ² In a study that compared the different algorithms showed a poor agreement between the methods. ³ A higher CVI value was found via Agrawal's method than the method described by Sonada et al. Therefore, it is not clear which of the two binarization algorithms is the most feasible in evaluating CVI. Those mentioned earlier can be considered the disadvantages of the CVI calculation methods. However, in studies conducted with different devices (Spectral domain versus Swept-source) using the same algorithm, good reliability between the measurements was obtained with the two different wavelengths has been reported. ⁴ Furthermore, our previous study observed good repeatability in CVI calculation using spectral-domain OCT in the healthy population regardless of age. ⁵ As a result, we think that CVI is a reproducible measurement method with high reliability.

When we get back to our study, firstly, the Figures 2(c) and 3(b) belong to different participants, which can be understood from the foveal contour. Therefore, the difference in brightness can be explained. Secondly, we included only healthy participants aged between 25 to 35, and there was no any media blurring cause such as corneal or lens-related pathologies that would affect the image quality in any of the patients. Finally, only the same participants’ images were compared in different time points rather than different patient groups in our study. Considering the abovementioned factors, we think that CVI measurements will not be affected. As a matter of fact, when we analyzed the study results, a very different CVI value was not observed at any point in any of the participants. Otherwise, inconsistent results for CVI from one figure to the next in the same participant should have occurred.