Comparison of the Peripapillary Structure-Vessel Density Relationship Before and After Axial Length Magnification...

Area of Science:

• Ophthalmology
• Medical Imaging
• Retinal Vascular Diseases

Background:

• High myopia presents challenges in accurately assessing retinal structures and vasculature using optical coherence tomography angiography (OCTA).
• Axial length (AL) magnification can introduce significant errors in OCTA-derived parameters.

Purpose of the Study:

• To evaluate changes in OCTA-derived structural and vascular parameters after axial length (AL) magnification correction.
• To compare two different magnification correction formulas and explore correlations with vessel density (VD).

Main Methods:

• 45 high myopic eyes and 45 controls underwent OCTA for optic nerve head imaging.
• Magnification correction was applied using the Bennett formula and the device's built-in algorithm.
• Analyzed parameters included RNFL thickness, superficial (SVC) and deep (DVC) vascular complex VD, and choroidal VD.

Main Results:

• Uncorrected scans in long AL eyes underestimated RNFL thickness and SVC VD, while overestimating DVC and choroidal VD.
• Correction significantly altered vascular parameters in high myopic eyes, with minimal changes in controls.
• RNFL thickness strongly correlated with SVC VD, and choroidal thickness (CT) with choroidal VD, both pre- and post-correction.

Conclusions:

• Magnification correction is crucial for accurate OCTA interpretation in high myopia.
• Correction effectively removed AL's confounding influence on RNFL and SVC VD.
• AL plays a significant mediating role in the relationship between CT and choroidal VD, particularly after correction.