Abstract
Abstract: :
Purpose: To investigate the feasibility of determining macular pigment optical density (MPOD) distribution from a single digital retinal image. Methods: A 3CCD, non–mydriatic retinal camera was modified by inserting a triple–bandpass filter in the light path between the flash lamp and subject's eye. As a result, the three CCDs responded principally to 460, 528 and 610 nm, respectively. Image analysis software was used to linearly combine the corresponding three (log transformed) monochrome images in order to generate an MPOD distribution map. Two different linear combinations of the images generated optical density maps of the cone photopigment and rod photopigments. The method assumes that the melanin and hemoglobin contributions to the images are uniform across the central retina. Retinal images were obtained without dilation or bleaching, from both eyes of 15 young subjects (17.3 + 1.3 years old). Results: As expected, MP and cone photopigment distributions peaked at the center of the macula, while the rod photopigment dipped in this region. Peak MPOD values, relative to baseline, ranged from 0.250 to 0.656 (mean 0.493 + 0.1298). Conclusions: The method shows promise as a simple, fast, objective means of assessing a subject's MPOD. It eliminates the need to bleach the cone and rod photopigments, or align separate images, as in traditional reflectometry.
Keywords: macular pigment • imaging/image analysis: non–clinical • carotenoids/carotenoid binding proteins