@article{TEXTUAL,
      recid = {10798},
      author = {Huchzermeyer, Cord and Schlomberg, Juliane and  Welge-Lüssen, Ulrich and Berendschot, Tos T. J. M. and  Pokorny, Joel and Kremers, Jan},
      title = {Macular Pigment Optical Density Measured by  Heterochromatic Modulation Photometry},
      journal = {PLOS ONE},
      address = {2014-10-29},
      number = {TEXTUAL},
      abstract = {&lt;p&gt;Purpose: To psychophysically determine macular pigment  optical density (MPOD) employing the heterochromatic  modulation photometry (HMP) paradigm by estimating 460 nm  absorption at central and peripheral retinal  locations.&lt;/p&gt;&lt;p&gt;Methods: For the HMP measurements, two  lights (B: 460 nm and R: 660 nm) were presented in a test  field and were modulated in counterphase at medium or high  frequencies. The contrasts of the two lights were varied in  tandem to determine flicker detection thresholds. Detection  thresholds were measured for different R:B modulation  ratios. The modulation ratio with minimal sensitivity  (maximal threshold) is the point of equiluminance.  Measurements were performed in 25 normal subjects (11 male,  14 female; age: 30±11 years, mean ± sd) using an eight  channel LED stimulator with Maxwellian view optics. The  results were compared with those from two published  techniques – one based on heterochromatic flicker  photometry (Macular Densitometer) and the other on fundus  reflectometry (MPR).&lt;/p&gt;&lt;p&gt;Results: We were able to  estimate MPOD with HMP using a modified theoretical model  that was fitted to the HMP data. The resultant  MPOD&lt;sub&gt;HMP&lt;/sub&gt; values correlated significantly with the  MPOD&lt;sub&gt;MPR&lt;/sub&gt; values and with the MPOD&lt;sub&gt;HFP&lt;/sub&gt;  values obtained at 0.25° and 0.5° retinal  eccentricity.&lt;/p&gt;&lt;p&gt;Conclusions: HMP is a flicker-based  method with measurements taken at a constant mean  chromaticity and luminance. The data can be well fit by a  model that allows all data points to contribute to the  photometric equality estimate. Therefore, we think that HMP  may be a useful method for MPOD measurements, in basic and  clinical vision experiments.&lt;/p&gt;},
      url = {http://knowledge.uchicago.edu/record/10798},
}