Minireview
Heterochromatic flicker photometry

https://doi.org/10.1016/j.abb.2004.04.003Get rights and content

Abstract

Measurement of the macular pigment optical density (MPOD) by heterochromatic flicker photometry (HFP) is accomplished by viewing a small circular stimulus that alternates between a test wavelength that is absorbed by the MP (typically— blue, 460 nm) and a reference wavelength that is not absorbed (typically—green, 540 nm). Flicker observed by the subject is reduced to a null point by adjusting the intensity of the former while viewing the stimulus centrally, and then peripherally. A higher intensity, I, of the blue component of the stimulus is needed under central viewing conditions owing to attenuation by the MP. The MPOD at the test wavelength is given by log (Icentral/Iperipheral). Variation of the test wavelength has been used to measure the MPOD spectrum. This in vitro MPOD spectrum matches that of the carotenoids present in the macular region of the retina and demonstrates the validity and specificity of this methodology. The distribution of MPOD in the retina can be determined with HFP using a series of annular stimuli of different diameters.

Section snippets

Instrumentation

The heterochromatic flicker photometer used in our studies is typical and will be described in detail. It is shown schematically in Fig. 1. A single 150 W quartz-halogen lamp is the source for the two components of the visual field. The advantage of a single source is that variation in the light output due to voltage fluctuations, aging of the lamp, etc., will affect both components and, to some extent, will be self-canceling. Lenses, mirrors, and interference filters are used to form

Results

Data from a group of 17 novices are presented in Fig. 2 in the form of a comparison between MPOD in their left and right eyes. The graph illustrates the typical SDs referred to earlier, as well as the similar optical densities that are usually measured by HFP in a subject's left and right eyes [10]. Fig. 3 shows a series of measurements made over a ∼6 month period by a highly experienced subject whose SD never exceeded 0.02. The day-to-day variability clearly exceeds the SD, but it is not clear

Discussion

There are several advantages of HFP as a method for determining MPOD. The method has been validated by the HFP-generated absorbance spectrum of the macular pigment which matches very closely those of lutein/zeaxanthin mixtures in appropriate lipid environments. Through the use of a reference (extra-foveal) measurement as well as a reference wavelength (540 nm), the results are independent of absorption or scattering in the optic media. With appropriately designed instruments, MPOD data can be

Acknowledgements

This work was supported in part by NIH Grant GM 08205.

References (20)

  • R.A. Bone et al.

    Vis. Res

    (1971)
  • J.T. Landrum et al.

    Exp. Eye Res

    (1997)
  • S. Beatty et al.

    Ophthal. Physiol. Opt

    (2000)
  • R.A. Bone et al.

    Vis. Res

    (1992)
  • J.S. Werner et al.

    Vis. Res

    (1987)
  • R.A. Bone et al.

    J. Nutr

    (2003)
  • J.W.T. Walsh

    Photometry

    (1953)
  • G. Wyszecki et al.

    Color Science

    (1982)
  • B.R. Wooten et al.

    Invest. Ophthalmol. Vis. Sci

    (1999)
  • H. de Lange Dzn

    J. Opt. Soc. Am

    (1958)
There are more references available in the full text version of this article.

Cited by (75)

  • Two fine-scale channels for encoding motion and stereopsis within the human magnocellular stream

    2023, Progress in Neurobiology
    Citation Excerpt :

    To localize color-selective sites, subjects were presented in separate blocks (24 s per block; Table S1) with sinusoidal gratings (0.2c/deg; 20° × 26°) which varied in either color (between red and blue) or achromatic luminance (Fig. 1C). For each subject, colors were adjusted to be equal in luminance across all eccentricities stimulated, using the method of flicker-photometry (Bone and Landrum, 2004; Ives, 1907) and according to each subject’s color perception (for more details see (Nasr et al., 2016)). In different blocks, orientation of colorful and achromatic gratings were either 0°, 45°, 90° or 135°, drifting in orthogonal directions (reversed every 6 s) at 4°/s.

  • The role of dark adaptation in understanding early AMD

    2022, Progress in Retinal and Eye Research
    Citation Excerpt :

    There are undoubted hypothetical benefits that are powerfully supported by the basic science and physiology, as discussed in a recent comprehensive review (Bernstein et al., 2016). MP can be measured using the psychophysical method of heterochromatic flicker photometry (HFP; Bone and Landrum, 2004), retinal reflectometry (Berendschot and van Norren, 2006), Raman microscopy (Bernstein et al., 1998) or an electrophysiological technique (Robson and Parry, 2008). We present the preliminary findings of a supplementation trial with L and Z using an HFP method (van der Veen et al., 2009) to estimate MP optical density over a one-year trial period.

  • Extraction, detection, and imaging of the macular carotenoids

    2022, Methods in Enzymology
    Citation Excerpt :

    Cumulative clinical and basic science research has shown that macular carotenoid levels are inversely associated with risk of age-related macular degeneration (AMD), and supplementation with the macular carotenoids is recommended to lessen the incidence of severe vision loss in patients with significant risk factors for advanced AMD (Age-Related Eye Disease Study 2 Research Group et al., 2014; Landrum et al., 1997; Seddon et al., 1994; Whitehead, Mares, & Danis, 2006). Moreover, several noninvasive methodologies for assessment of macular pigment optical density (MPOD) have been explored to identify individuals who may benefit from pre-symptomatic supplementation with macular carotenoids and to monitor their response to intervention (Bernstein et al., 2012; Bone & Landrum, 2004; Nolan, Stack, O'Connell, & Beatty, 2007; Snodderly et al., 2004). Lutein, zeaxanthin, and meso-zeaxanthin are configurational and structural isomers that share the same molecular formula, C40H56O2 (Fig. 1).

  • Columnar organization of mid-spectral and end-spectral hue preferences in human visual cortex

    2018, NeuroImage
    Citation Excerpt :

    In each subject, the mean luminance level was equated for each hue-varying grating. Specifically, mean luminance values for red, yellow, green, and achromatic gray were defined based on the method of flicker photometry (Ives, 1907; Bone and Landrum, 2004; Nasr et al., 2016). The luminance for all hues was set to the limiting (maximum) luminance for blue (i.e. 4.8 Ft.-L.) (see below).

View all citing articles on Scopus
View full text