June 2022
Volume 11, Issue 6
Open Access
Letters to the Editor  |   June 2022
Author Response: Changes in Choroidal Vascularity Index in Intermediate Uveitis
Author Affiliations
  • Wijak Kongwattananon
    National Eye Institute, National Institutes of Health, Bethesda, MD, USA
    Vitreoretinal Research Unit, Department of Ophthalmology, Faculty of Medicine, Chulalongkorn University and King Chulalongkorn Memorial Hospital, Thai Red Cross Society, Bangkok, Thailand
  • Aman Kumar
    Vitreoretinal Research Unit, Department of Ophthalmology, Faculty of Medicine, Chulalongkorn University and King Chulalongkorn Memorial Hospital, Thai Red Cross Society, Bangkok, Thailand
    Albany Medical College, Albany, NY, USA. e-mail: drwijak@gmail.com.
  • Enny Oyeniran
    National Eye Institute, National Institutes of Health, Bethesda, MD, USA
  • H. Nida Sen
    National Eye Institute, National Institutes of Health, Bethesda, MD, USA
  • Shilpa Kodati
    National Eye Institute, National Institutes of Health, Bethesda, MD, USA
Translational Vision Science & Technology June 2022, Vol.11, 6. doi:https://doi.org/10.1167/tvst.11.6.6
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    • Get Citation

      Wijak Kongwattananon, Aman Kumar, Enny Oyeniran, H. Nida Sen, Shilpa Kodati; Author Response: Changes in Choroidal Vascularity Index in Intermediate Uveitis. Trans. Vis. Sci. Tech. 2022;11(6):6. doi: https://doi.org/10.1167/tvst.11.6.6.

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      © ARVO (1962-2015); The Authors (2016-present)

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  • Supplements
We appreciate the comments by Costigliola et al. on our recent published study “Changes in Choroidal Vascularity Index (CVI) in Intermediate Uveitis.”5 
We acknowledge that the CVI could be affected by the blooming effect,13 resulting in either an overestimation or underestimation of the CVI value. However, efforts were made to standardize the CVI calculation. 
Previously, Vupparaboina et al.4 determined whether shadow compensation has an influence on CVI calculation. Shadow compensation is the processing algorithm used to enhance the contrast between the vascular lumen and choroidal stroma. In a shadow compensated optical coherence tomography (OCT) scan, the choroid will appear with greater brightness than neurosensory retina. In their results, the mean CVI in shadow-compensated scans was significantly higher than in raw scans, confirming that shadow compensation potentially affects CVI measurement. 
There are reasons we believe that the blooming effect was minimized in our study. First, image saturation and contrast were set at the same value for all OCT images before CVI measurement. Second, a default setting of the OCT platform was used to obtain OCT scans throughout the study period. Last, we applied our algorithm to outline the boundary of total choroidal area using prespecified polygonal tools in ImageJ. Therefore, the size of total choroidal area was standardized. 
Nevertheless, we acknowledge that CVI measurements do have their limitations and excluded poor quality OCT images, including those caused by significant ocular media opacity and images without a distinguishable sclerochoroidal junction. We had noted that further adjustment for contrast and brightness by the grader was necessary to better distinguish between luminal and stroma. As a result, the CVI values in these images greatly depended on each grader's settings, resulting in high variability in CVI calculation, resulting in the need for these images to be excluded 
In summary, we have standardized our CVI measurement by using a default setting of OCT platform and controlled OCT image parameters. We would like to highlight that these steps are important to consider when calculating the CVI to obtain an accurate CVI value. 
References
De Bernardo M, Vitiello L, Rosa N. Ultrasound optic nerve sheath diameter evaluation in patients undergoing robot-assisted laparoscopic pelvic surgery. J Robot Surg. 2019; 13: 709–710 [CrossRef] [PubMed]
De Bernardo M, Vitiello L, Rosa N. Optic nerve evaluation in idiopathic intracranial 45 hypertension. AJNR Am J Neuroradiol. 2019; 40`: E36. [CrossRef] [PubMed]
Vitiello L, De Bernardo M, Capasso L, Cornetta P, Rosa N. Optic nerve ultrasound evaluation 47 in animals and normal subjects. Front Med (Lausanne). 2022; 8: 797018. [CrossRef] [PubMed]
Vupparaboina KK, Dansingani KK, Goud A, et al. Quantitative shadow compensated optical coherence tomography of choroidal vasculature. Sci Rep. 2018; 8: 1–9. [PubMed]
Kongwattananon W, Kumar A, Oyeniran E, Sen HN, Kodati S. Changes in choroidal vascularity index (CVI) in intermediate uveitis. Transl Vis Sci Technol. 2021; 10(14): 33. [CrossRef] [PubMed]
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