Retinal Vessel Local Tortuosity under a Macula-to-Optic Disc Central-Framing Change

Area of Science:

• Ophthalmology and Medical Imaging
• Biomedical Engineering
• Cardiovascular Disease Research

Background:

• Increased retinal blood vessel tortuosity is linked to ocular and cardiovascular diseases.
• Retinal imaging analysis offers objective tortuosity measurements.
• The impact of image analysis parameters on tortuosity indices requires investigation.

Purpose of the Study:

• To evaluate the sensitivity of local tortuosity indices to changes in the image frame center (macula vs. optic disc).
• To identify robust tortuosity indices for clinical application in retinal imaging.

Main Methods:

• Analysis of 40 pairs of retinal blood vessels using eight different tortuosity indices.
• Systematic variation of the image frame center (macula and optic disc).
• Statistical comparison of tortuosity index values under different frame center conditions.

Main Results:

• Significant differences in mean tortuosity values were observed for most indices when the frame center changed.
• The index based on the ratio of curvature to arc length demonstrated the highest robustness against frame center variations.
• Experimental validation using clinical retinal images was performed.

Conclusions:

• The choice of frame center in retinal image analysis significantly affects most tortuosity measurements.
• The curvature-to-arc-length ratio is a more reliable index for assessing retinal vessel tortuosity.
• Robust tortuosity measures are crucial for accurate disease detection from retinal images.