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    The MPS II; comparison with the Macular Pigment Reflectometer and the Macular Densitometer

    L Patryas, J Cher, IYF Leung, K Neelam, M Makridaki, D Carden, TTJM Berendschot, RLP van der Veen & IJ Murray

    In: Macular Carotenoid Conference; Cambridge. 2013.

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    Abstract

    Purpose: Measuring macular pigment optical density (MPOD) with different methods appear to produce differing results in the same individuals, especially when dissimilar principles are employed. Ascertaining to what degree these methods correlate will enable the scientific community to interpret past and future research studies in this field. Here we describe two series of experiments which compare recent techniques used to measure MPOD. Methods: First, we used a macular pigment reflectometer1 (MPR) with capture angle 1, modified to measure at eccentricities of 0, 1, 2, 4, 6 and 8. These data were compared with those obtained from the Macular Pigment Screener2 (MPS) modified to assess MPOD at 0.5, 1, 2, 4, 5, 6 and 7. Nineteen healthy individuals (mean age 26 8 years) were tested. In a second experiment, we compared the right eyes of twenty-five healthy individuals (mean age 23 3 years) using MPS and a Macular Densitometer2 (MD).Results: There was a strong correlation between the MPR and the MPR techniques (r = 0.72, p = 0.001) with the absolute estimates obtained by MPS being lower than by MPR. These differences could be explained by i) non-zero values at 8 eccentricity and ii) assuming the subjects used a point 0.4 from the centre of the stimulus to set flicker thresholds. The correlation between the MPS and MD was high (r = 0.82, p < 0.0001), with the MPS again producing lower absolute values. Repeatability was assessed with 10 individuals. Coefficients of repeatability for MPD and MPS were 0.21 and 0.06, respectively. Conclusions: The MPS, the MPR and the MD provide broadly similar results. It is inevitable that different absolute values are obtained, The important factor is the predictability from one method to another. It is essential that practitioners obtain normative data for any particular instrument as it is well known that many factors influence the assessment of MPOD. The MPS has the advantage of the centre-only facility, designed for clinical practice. This enables rapid determination of MPOD and is ideal when differences between consecutive measurements are required when monitoring the results of supplementing with retinal carotenoidsDisclosures: The MPS is protected by a patent owned by Ian Murray and David Carden.References 1. van de Kraats J, Berendschot TT, Valen S, & van Norren D (2006): Fast assessment of the central macular pigment density with natural pupil using the macular pigment reflectometer. J Biomed Opt 11(6):064031.2. van der Veen RL, Berendschot TT, Makridaki M, Hendrikse F, Carden D & Murray IJ (2009): Correspondence between retinal reflectometry and a flicker-based technique in the measurement of macular pigment spatial profiles. J Biomed Opt.14(6):064046. 3. Wooten BR, Hammond BR, Land RI & Snodderly DM (1999): A practical method for measuring macular pigment optical density. Invest Ophthalmol Vis Sci 40:2481–2489.

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    Type of resource:
    Content type:
    Type of conference contribution:
    Publication date:
    Conference title:
    Macular Carotenoid Conference
    Conference venue:
    Cambridge
    Abstract:
    Purpose: Measuring macular pigment optical density (MPOD) with different methods appear to produce differing results in the same individuals, especially when dissimilar principles are employed. Ascertaining to what degree these methods correlate will enable the scientific community to interpret past and future research studies in this field. Here we describe two series of experiments which compare recent techniques used to measure MPOD. Methods: First, we used a macular pigment reflectometer1 (MPR) with capture angle 1, modified to measure at eccentricities of 0, 1, 2, 4, 6 and 8. These data were compared with those obtained from the Macular Pigment Screener2 (MPS) modified to assess MPOD at 0.5, 1, 2, 4, 5, 6 and 7. Nineteen healthy individuals (mean age 26 8 years) were tested. In a second experiment, we compared the right eyes of twenty-five healthy individuals (mean age 23 3 years) using MPS and a Macular Densitometer2 (MD).Results: There was a strong correlation between the MPR and the MPR techniques (r = 0.72, p = 0.001) with the absolute estimates obtained by MPS being lower than by MPR. These differences could be explained by i) non-zero values at 8 eccentricity and ii) assuming the subjects used a point 0.4 from the centre of the stimulus to set flicker thresholds. The correlation between the MPS and MD was high (r = 0.82, p < 0.0001), with the MPS again producing lower absolute values. Repeatability was assessed with 10 individuals. Coefficients of repeatability for MPD and MPS were 0.21 and 0.06, respectively. Conclusions: The MPS, the MPR and the MD provide broadly similar results. It is inevitable that different absolute values are obtained, The important factor is the predictability from one method to another. It is essential that practitioners obtain normative data for any particular instrument as it is well known that many factors influence the assessment of MPOD. The MPS has the advantage of the centre-only facility, designed for clinical practice. This enables rapid determination of MPOD and is ideal when differences between consecutive measurements are required when monitoring the results of supplementing with retinal carotenoidsDisclosures: The MPS is protected by a patent owned by Ian Murray and David Carden.References 1. van de Kraats J, Berendschot TT, Valen S, & van Norren D (2006): Fast assessment of the central macular pigment density with natural pupil using the macular pigment reflectometer. J Biomed Opt 11(6):064031.2. van der Veen RL, Berendschot TT, Makridaki M, Hendrikse F, Carden D & Murray IJ (2009): Correspondence between retinal reflectometry and a flicker-based technique in the measurement of macular pigment spatial profiles. J Biomed Opt.14(6):064046. 3. Wooten BR, Hammond BR, Land RI & Snodderly DM (1999): A practical method for measuring macular pigment optical density. Invest Ophthalmol Vis Sci 40:2481–2489.

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    Manchester eScholar ID:
    uk-ac-man-scw:225960
    Created by:
    Patryas, Laura
    Created:
    28th May, 2014, 14:40:22
    Last modified by:
    Patryas, Laura
    Last modified:
    22nd April, 2015, 23:20:45

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