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

Area of Science:

• Ophthalmology
• Medical Imaging
• Human Anatomy

Background:

• Myopia, or nearsightedness, is a prevalent refractive error with significant public health implications.
• Choroidal changes are increasingly recognized as a key factor in myopia development and progression.
• Understanding the detailed vascular and morphological characteristics of the choroid in myopia is crucial for developing effective interventions.

Purpose of the Study:

• To investigate the detailed vascular and morphological characteristics of choroidal tissue in relation to myopia severity.
• To compare choroidal thickness, area, and vascularity index across different myopia groups.

Main Methods:

• 111 myopic subjects were categorized into low (≤-3.00 D), moderate (-3.25 to -6.00 D), and high (≥-6.25 D) myopia groups based on spherical equivalent (SE).
• Measurements included 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).
• Binarization methods were used to calculate TCA, LA, SA, LA/SA ratio, and CVI, followed by inter-group comparisons.

Main Results:

• High myopia was associated with significantly thinner choroids (CT) compared to moderate and low myopia (p<0.001).
• Lower myopia groups showed higher LA, SA, and TCA, while high myopia exhibited increased LA/SA ratio and CVI.
• Significant negative correlations were found between CVI/LA/SA ratio and SE, and positive correlations with AL.

Conclusions:

• High myopia in young adults is characterized by significant macular choroidal thinning.
• This thinning is primarily due to a reduction in the stromal component of the choroid.
• The vascular (luminal) component appears less affected, suggesting a stromal-driven process in myopia-related choroidal changes.