To the Editor:
We read with great interest the article by Şimşek et al. concerning the evaluation of retinal and choroidal microcirculation in Behçet’s disease (BD) [1]. We congratulate the authors for their very interesting study, but we would like to make some comments.
The authors found vessel density values of the superficial and deep macular capillary plexus to be similar between BD group and control, with no significant difference in terms of choroidal thickness and total choroidal area values in the macula and in all peripapillary sectors. This seems to contradict the finding of significantly lower choroidal vascularity index (CVI) values in the BD group compared with controls in the macula and temporal, nasal, and inferior sectors of the peripapillary area.
In our opinion, the reason for this could be the so called blooming effect, which is well known in the echographic B scan [2, 3]. This effect is related to signal amplification. In particular when high signal amplification is used, the image will appear brighter, and the amount of white pixels will be greater; the opposite will happen using a low setting. This artifact could influence the binarization utilized in the CVI evaluation, increasing the low reflective areas, considered to be the luminal ones, when the amplification is low, and reducing them when the amplification is higher, making the results unreliable [4, 5].
Author contributions
CS, AM and MDB wrote this letter.
Competing interests
The authors declare no competing interests.
Footnotes
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References
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