title: Macular pigment shows ringlike structures.
abstract: OBJECTIVE
  The spatial distribution of macular pigment is generally assumed to monotonously decrease to very low values in the periphery. However, there are indications that this picture may be too simple. The purpose of this study was to examine the spatial distribution of the macular pigment optical density.
  
  
  METHODS
  Fundus reflectance and autofluorescence maps at 488 and 514 nm Argon laser wavelengths were acquired in 53 healthy subjects with a custom-built scanning laser ophthalmoscope. Because the lens and the macular pigment are the only absorbers in this wavelength region, digital subtraction of log reflectance and log autofluorescence at the two wavelengths provides density maps of the sum of both absorbers.
  
  
  RESULTS
  In approximately half of the subjects, we observed a distinct ring pattern at a mean distance of 0.7 degrees of the fovea. In a few subjects, the ring had an even larger optical density than did the central peak. A simple model with an exponentially decaying density as a function of eccentricity, in combination with a Gaussian-distributed ring pattern, yielded a good description of the data for both methods. The widths of the central peak and the Gaussian ring, and also the eccentricity at which the ring peaks, were similar for both methods. The prominence of the ring did not depend on age and gender.
  
  
  CONCLUSIONS
  Both reflectance and autofluorescence maps showed ring patterns in the distribution of the macular pigment, which probably follow the inner plexiform layer.
authors.affiliation: University Eye Clinic Maastricht, Maastricht, The Netherlands. t.berendschot@ohk.unimass.nl
authors.forename: Tos T J M
authors.initials: TT
authors.lastname: Berendschot
authors.forename: Dirk
authors.initials: D
authors.lastname: van Norren
mesh_terms: D000328:Adult; D005260:Female; D005453:Fluorescence; D006801:Humans; D007834:Lasers; D014975:Lutein / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D019721:Ophthalmoscopes; D012160:Retina / Q000378:metabolism*; D012168:Retinal Pigments / Q000378:metabolism*; D024341:Xanthophylls; D065146:Zeaxanthins; D019207:beta Carotene / Q000031:analogs & derivatives* / Q000378:metabolism
chemical_list: D012168:Retinal Pigments; D024341:Xanthophylls; D065146:Zeaxanthins; D019207:beta Carotene; D014975:Lutein