Effects of age and binarising area on choroidal vascularity index in healthy eyes: an optical coherence tomography study.

Purpose:  To investigate the changes in the choroidal vascularity index (CVI) with age and to compare the effect of the binarised area on CVI in healthy eyes using spectral-domain optical coherence tomography (SD-OCT).

Materials And Methods:  Two hundred and twenty-four eyes of 224 healthy subjects were included in this prospective cross-sectional study. The eyes were divided into different age groups to analyse the possible age-related choroidal structural changes. Subfoveal choroidal thickness (SFCT), CVI, total choroidal area (TCA), stromal area (SA), luminal area (LA), and CVI within the central 1500 µm of the macula were analysed using enhanced depth imaging SD-OCT. The CVI was defined as the proportion of the LA to the TCA, and its values for the two binarised areas were compared (CVI vs. CVI).

Results:  The mean age was 34.77 ± 20.97 (range: 5-70) years. The mean CVI was statistically lower (66.71 ± 2.58%) than the mean CVI (67.54 ± 3.13%, p = 0.008) among all the healthy participants. TCA, LA, CVI, and CVI were statistically higher in the ≤ 18-year-old group compared to the > 18-year-old group (p < 0.05), but SA was not significantly different between the groups (p = 0.327). Similarly, TCA, LA, CVI, and CVI between the five studied age groups were statistically different (p < 0.001), showing larger figures in the 0-10-year-old group. However, this was not true for the stromal region (p = 0.139). CVI exhibited a very strong positive correlation with CVI. No significant gender-related difference was observed in CVI.

Conclusion: Decreased LA, TCA, and CVI were observed in healthy eyes with increasing age. CVI was higher than CVI in a single B scan OCT. This result may provide valuable information about the choroid under different conditions, such as its physiological changes and disease pathophysiology.