title: A practical method for measuring macular pigment optical density.
abstract: OBJECTIVE
  Increasing evidence indicates that the macular pigments (MP) protect the central retina and may retard macular disease. For that reason, a practical method for measuring MP that does not require elaborate optics and can be applied to diverse populations by operators with a modest amount of experience was developed and validated.
  
  
  METHODS
  A small tabletop device based on light-emitting diodes (LEDs) as the light source with electronic controls was constructed. Macular pigment was measured with the tabletop device with a 1 degrees test stimulus at 460 nm using heterochromatic flicker photometry, and the results were compared with measurements using a traditional three-channel Maxwellian view system with a xenon-arc source.
  
  
  RESULTS
  Macular pigment density of 30 subjects (age range, 16-60 years) was measured with both stimulus systems. Macular pigment measured with the LED tabletop device in free view was highly correlated with MP measured in Maxwellian view (y = -0.03 + 1.06x, r = +0.95). The average absolute difference between the two techniques was 0.04 (SD, 0.03). The new technique was not significantly affected by variations in lens optical density, pupil size, or small head movements.
  
  
  CONCLUSIONS
  Psychophysical measurement of MP provides a unique opportunity to make repeated noninvasive assessment of the concentration of a protective nutrient in the retina. The availability of this new device should make this measurement technology accessible to a wide variety of investigators for application to diverse populations.
authors.affiliation: Department of Psychology, Brown University, Providence, Rhode Island, USA.
authors.forename: B R
authors.initials: BR
authors.lastname: Wooten
authors.forename: B R
authors.initials: BR
authors.lastname: Hammond
authors.forename: R I
authors.initials: RI
authors.lastname: Land
authors.forename: D M
authors.initials: DM
authors.lastname: Snodderly
mesh_terms: D000293:Adolescent; D000328:Adult; D003941:Diagnostic Techniques, Ophthalmological / Q000295:instrumentation*; D005260:Female; D006801:Humans; D008266:Macula Lutea / Q000737:chemistry*; D008297:Male; D008875:Middle Aged; D012168:Retinal Pigments / Q000032:analysis*
chemical_list: D012168:Retinal Pigments