| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
1From the Waterford Institute of Technology, Waterford, Republic of Ireland; the 2Waterford Regional Hospital, Waterford, Republic of Ireland; the 3Clinical Trials and Epidemiology Research Unit, Singapore; and the 4Alexandra Hospital, National Healthcare Group, Singapore.
PURPOSE. There are several techniques for measuring macular pigment (MP) in vivo, of which Raman spectroscopy (RS) is a recently developed objective method. This study reports the reproducibility, test–retest variability, and validity of RS MP readings, by comparing them with heterochromatic flicker photometry (HFP).
METHODS. MP was measured with HFP and RS in 120 healthy subjects, and the latter technique was also used on two separate occasions in a sample of 20 subjects to investigate the intersessional variability of readings. Intrasessional reproducibility of RS MP measurements was also calculated. In addition, serum concentrations of lutein (L) and zeaxanthin (Z) were measured and correlated with both RS and HFP MP readings.
RESULTS. Mean (±SD) MP in the right eye was 0.279 ± 0.145 and 0.319 ± 0.155 with RS and HFP, respectively. The differences between corresponding MP readings taken on RS and HFP lay within the Bland-Altman 95% limits of agreement for the two instruments in 93.6% and 94.4% of cases in the right and left eyes, respectively. Intrasessional reproducibility of RS readings, expressed as the coefficient of variation, was 8.42% ± 7.12%. Ninety-five percent of MP readings taken with RS on two separate occasions lay within the 95% limits of agreement for the two sessions. A positive, but insignificant, relationship was observed between RS and HFP MP readings and serum concentrations of L and Z (RS, P = 0.356; HFP, P = 0.540).
CONCLUSIONS. RS, an objective method of measuring MP levels in vivo, exhibits acceptable reproducibility and test–retest variability. The results demonstrated good correlation between RS and HFP measurements of MP, thus authenticating RS against a validated psychophysical technique of measuring MP. However, investigators should use only one of these instruments for the duration of any given study because of differences in the scientific rationale, and the factors that influence RS and HFP measurements of MP.
This article has been cited by other articles:
|
|
 |
|
  S. Beatty, F. J. G. M. van Kuijk, and U. Chakravarthy Macular Pigment and Age-Related Macular Degeneration: Longitudinal Data and Better Techniques of Measurement Are Needed Invest. Ophthalmol. Vis. Sci., March 1, 2008; 49(3): 843 - 845. [Full Text] [PDF]
|
|
|
|
 |
|
 R E Hogg, R S Anderson, M R Stevenson, M B Zlatkova, and U Chakravarthy In vivo macular pigment measurements: a comparison of resonance Raman spectroscopy and heterochromatic flicker photometry Br. J. Ophthalmol., April 1, 2007; 91(4): 485 - 490. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
P. Bhosale, D. Y. Zhao, and P. S. Bernstein HPLC Measurement of Ocular Carotenoid Levels in Human Donor Eyes in the Lutein Supplementation Era Invest. Ophthalmol. Vis. Sci., February 1, 2007; 48(2): 543 - 549. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J. M. Nolan, J. Stack, E. O'Connell, and S. Beatty The Relationships between Macular Pigment Optical Density and Its Constituent Carotenoids in Diet and Serum Invest. Ophthalmol. Vis. Sci., February 1, 2007; 48(2): 571 - 582. [Abstract] [Full Text] [PDF]
|
|
Read all eLetters
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
