In this study, we investigated the potential correlation between MP measurements obtained with the MPS II technology and quantitative measurements of the autofluorescence (qAF). Interestingly, a negative and statistically significant correlation between MPOD
HFP and log (qAF) has been found in the central area up to approximately 4.3° (−0.60 and −0.38, for the qAF
F and qAF
3 respectively;
P < 0.01), while in the more eccentric region (qAF
6) no correlation was found. This negative correlation mainly relies on the high concentration of macular pigment in the foveal area, absorbing the FAF blue-light masking retinal fluorophores, while the lack of correlation found between qAF
6 and MPOD
HFP is probably due to the decrease in macular pigment concentration from the foveal region to more peripheral areas. The investigated area, which is a function of the radius of the chosen reference, critically improves its dimensions compared to qAF
3, making of the more peripheral segments the most consistent part to determine the mean qAF. Although several factors can influence retinal pigment distribution (which in the 40% of healthy eyes does not follow a Gaussian distribution),
3 our results suggest that qAF values can be able to reflect its concentration. In particular, the lower are the values of qAF, the higher is the concentration of MP. A direct estimate of MPOD from qAF values (
Equation 5), in order to directly compare the values with those from the MPS II, was also performed. In the qAF
F area
, MPOD
AF was 0.82 DU, compared to 0.47 DU obtained with the HFP, This discrepancy can be partially explained by the different sampling apertures of the instruments (1° and 2.4° diameter for HFP and qAF, respectively) and by the intrinsic limit of the single-wavelength AF, that provides AF values from MP and even the RPE, resulting in an overestimation of the measurements. Delori et al.
18 estimated that the fluorescence in the fovea was on average 61% ± 9% of its value at 7° temporal. By applying a correction formula to consider the gap between foveal and peripheral AF values due to lipofuscin autofluorescence, MPOD
AF values were reduced to 0.54 DU, more similar to those obtained with HFP technique. Although the formula for direct MPOD estimation is suitable for double-wavelength systems, a positive correlation between qAF
F and MPS II MPOD values was found, somehow enforcing our findings and suggesting its possible employment in the clinical practice.