What is the relationship between the choroidal vascularity ındex (CVI) and myopia?

Abstract

Purpose: To examine the detailed vascular and morphological characteristics of the choroidal tissue in subjects with myopia.

Methods: A total of 111 subjects with myopia were included in the study. The study was conducted in three groups according to spherical equivalent(SE). Group 1 comprised subjects with low myopia (SE between 0.00 diopter (D) and - 3.00 D), Group 2 included those with moderate myopia (SE between - 3.25 D and - 6.00 D), and Group 3 consisted of subjects with high myopia (SE of - 6.25 D or worse). The following parameters were measured: axial length(AL), SE, central macular thickness (CMT), choroidal thickness(CT), total choroidal area(TCA), luminal area(LA), stromal area(SA), LA/SA ratio, and choroidal vascularity index(CVI). The binarization method was employed to calculate the TCA, LA, SA, LA/SA ratio, and CVI values. A comparison was conducted between the groups with respect to all parameters.

Results: In patients with high myopia, CT values (subfoveal, nasal, and temporal) were significantly thinner than moderate and low myopic patients (< 0.001). The low myopic group exhibited significantly elevated LA, SA, and TCA values in comparison to the moderate and high myopic groups. Conversely, the LA/SA ratio and CVI values were observed to be higher in patients with high myopia than in those with low or moderate myopia. A statistically significant negative correlation was identified between CVI and LA/SA values and SE(r = - 0.270, P = 0.004; r = - 0.291, P = 0.002, respectively). A statistically significant positive correlation was identified between CVI and LA/SA values and AL (r = 0.269, P = 0.004; r = 0.281, P = 0.003, respectively).

Conclusion: In young adults, high myopia has been linked to significant choroidal thinning in the macular region. This reduction in choroidal thickness is largely attributed to a decrease in the stromal component of the choroid, rather than the luminal (vascular) component.

Trial registration date and number: 08/06/2022, 2022-49.