Impact of Brightness on Choroidal Vascularity Index

The use of choroidal vascularization to diagnose and follow-up ocular and systemic pathologies has been consolidated in recent research. Unfortunately, the choroidal parameters can be different depending on the lighting settings of optical coherence tomography (OCT) images. The purpose of this study was to examine whether the brightness of OCT images could influence the measurements of choroidal parameters obtained by processing and analyzing scientific images with the ImageJ program. In this observational, prospective, non-randomized study, 148 eyes of 74 patients with a mean age of 30.7 +/- 8.5 years (ranging from 23 to 61 years) were assessed. All patients underwent a complete ophthalmological examination including slit lamp, fundus oculi, ocular biometry, corneal tomography and spectral domain (SD) OCT evaluations of the foveal region in the enhanced depth imaging (EDI) mode. OCT images at two different brightness levels were obtained. The total choroidal area (TCA), choroidal vascularity index (CVI), stromal choroidal area (SCA) and luminal choroidal area (LCA) at both lower and higher brightness levels were measured. To avoid the bias of operator-dependent error, the lower and higher brightness TCAs were obtained using two methods: the manual tracking mode and fixed area. At the two different brightness levels, LCA, SCA and CVI measurements showed statistically significant changes (p < 0.05), whereas the TCA differences were not statistically significant (p > 0.05). According to the results of this study, highlighting that brightness could affect LCA, SCA and CVI parameters, care should be taken during OCT image acquisition.