Purpose: Clinical investigations have demonstrated variation in both the peak optical density and the spatial distribution of macular pigment. To confirm these impressions histologically, the present study examined the distribution of macular pigment in the human retina.
Materials and methods: The macular retina of 11 donor eyes of different ages (28-91 years) were examined histologically on 100 microm vibratome sections directly, without further staining. Measurements were made in two dimensions: (1) adding the number of macular sections with visible macular pigment, and (2) direct measurement of the extension of macular pigment in the foveolar section, which visibly contained the most macular pigment.
Results: The measurements with two methods demonstrated good correlation. The macula demonstrated a variation in the spatial extension of the visible macular pigment between 200 and 900 microm diameter around the centre of the fovea, which was also found when direct measurements were taken. There was no correlation with the donor age. The main location of macular pigment was in the layer of the fibres of Henle in the fovea and in the inner nuclear layer at the parafoveal site.
Conclusions: Histologically, a wide variation of the spatial distribution of macular pigment was found that confirms clinical observations. The primary localization of human macular pigment is in the inner retinal layers.