A novel computational model for human macular pigment optical density and its relationship to foveal structure

Macular pigment optical density (MPOD) models enhance understanding of macular xanthophyll distribution, particularly relevant to age-related macular degeneration. This study investigates an existing model and introduces a novel, more accurate and biologically relevant approach. MPOD spatial profiles of 48 eyes were obtained using dual-wavelength autofluorescence imaging, with structural data from OCT and OCT-angiography. MPOD data were analyzed using (a) an existing sum of exponential and Gaussian model (M_EG) and (b) a novel sum of three Gaussians model (M_3G). Extracted parameters generated individualized MPOD models, from which gradients and volumes were derived. M_3G-derived variables were analyzed against OCT/OCTA data using factor analysis and multiple regression. M_3G demonstrated a superior fit to MPOD data (SSE = 2.60 × 10^{− 3}) compared to M_EG, (SSE = 35.7 × 10^{− 3}) enabling automated fitting consistent over small and large datasets. M_3G provided meaningful variables, including MPOD gradients, volumes and critical point eccentricities. Correlations included those between dependent variables of critical point eccentricities and central macular pigment volume with foveal avascular zone and foveal pit radii. The excellent data fit of M_3G enables automated extraction of physiologically relevant parameters. Its three-component configuration is consistent with the location of macular xanthophylls. M_3G is similar to models of foveal structure, suggesting a fundamental relationship.