Abstract
Purpose: :
We compared macular pigment optical density (MPOD) spatial profiles measured by customized heterochromatic flicker photometry (cHFP) and two-wavelength autofluorescence (AF) imaging. Spectral domain optical coherence tomography (SD-OCT) was used to compare the MPOD distribution with foveal architecture.
Methods: :
15 healthy subjects were recruited to measure their MPOD spatial profiles out to 7° retinal eccentricity using cHFP and two-wavelength AF methods (fundus camera and Heidelberg HRA MP). The spatial profile of MPOD as a function of eccentricity was compared for the two methods. Measurements of central foveal thickness, width of the foveal pit, and arrangements of the foveal layers were extracted from OCT scans in a subset of the subjects to investigate relationships to the MPOD distribution using the Heidelberg Spectralis SD-OCT.
Results: :
cHFP generated reproducible measurements of the MPOD spatial profiles for all subjects. There was a close relationship between the MPOD spatial profiles measured using cHFP and two-wavelength AF, including details of the shape of the profile. Our preliminary results support the idea that a wider fovea is associated with a wider macular pigment spatial profile that can include a central peak and flanking peaks. A narrow fovea is likely to have a steeper macular pigment distribution that more closely approximates an exponential spatial profile. The Henle Fiber layer thickness decreases rapidly with increasing retinal eccentricity in subjects with narrower foveal pits when compared to those with wider foveas.
Conclusions: :
Investigators have a choice of methods to measure MPOD spatial profiles, and the profiles are systematically linked to the foveal architecture. The AF method requires less involvement of the subject, but requires unpleasant light levels and pupillary dilation. The cHFP method requires more subject participation, but does not require pupillary dilation, which facilitates its use in a nonclinical setting
Keywords: macula/fovea • macular pigment • retina