Measurement of macular fractal dimension using a computer-assisted program

Area of Science:

• Ophthalmology
• Medical Imaging
• Biomedical Engineering

Background:

• Macular diseases are linked to changes in retinal vasculature.
• Quantifying retinal vascular complexity is crucial for understanding these diseases.
• Fractal dimension (Df) offers a method to measure vascular complexity.

Purpose of the Study:

• To introduce and validate new software for measuring retinal vascular fractal dimension (Df) at the macula (D mac) and optic disc (D disc).
• To assess the reliability of the software in quantifying macular and optic disc vascular complexity.
• To compare D mac and D disc measurements and identify associated factors.

Main Methods:

• Utilized 342 macular and optic disc retinal photographs from a population-based study.
• Employed computer-assisted software (SIVA-FA) for measuring retinal vascular fractal dimension (Df).
• Assessed intragrader, intergrader, and intrasession reliability using intraclass correlation coefficients (ICCs) and performed regression analyses.

Main Results:

• Mean D mac was 1.453 (0.060) and mean D disc was 1.484 (0.043), showing a strong correlation (r = 0.70).
• High reliability was found for Df measures (ICCs 0.88-0.99).
• Age and hypertension were independently associated with both D mac and D disc measurements.

Conclusions:

• The developed software reliably measures retinal vascular complexity in the macula.
• This tool is potentially valuable for studying parafoveal vascular networks in macular diseases.
• Findings support the use of Df measurement in clinical research for conditions like diabetic maculopathy.