REVIEW The role of macular pigment assessment in clinical practice: a review Clin Exp Optom 2010; 93: 5: 300–308 DOI:10.1111/j.1444-0938.2010.00499.x Hannah Bartlett BSc (Hons) MCOptom PhD FAAO Olivia Howells BSc (Hons) MCOptom Frank Eperjesi BSC (Hons) MCOptom PhD FAAO MBA Ophthalmic Research Group, School of Life & Health Sciences, Aston University, Birmingham, United Kingdom E-mail: h.e.bartlett@aston.ac.uk This review compares the results of studies that have investigated the impact of lutein and zeaxanthin supplementation on macular pigment optical density (MPOD) with those that have investigated the reliability of techniques used to measure macular pigment optical density. The review will focus on studies that have used heterochromatic flicker photometry for measurement of macular pigment optical density, as this is the only technique that is currently available commercially to clinicians. We identified articles that reported on supplementation with lutein and/or zeaxanthin and/or meso-zeaxanthin on macular pigment optical density measurement techniques published in peer-reviewed journals, through a multi-staged, systematic approach. Twenty-four studies have investi- gated the repeatability of MPOD measurements using heterochromatic flicker photom- etry. Of these, 10 studies provided a coefficient of repeatability or data from which the coefficient could be calculated, with a range in values of 0.06 to 0.58. The lowest coefficient of repeatability assessed on naïve subjects alone was 0.08. These values tell us that, at best, changes greater than 0.08 can be considered clinically significant and at worst, only changes greater than 0.58 can be considered clinically significant. Six studies assessed the effect of supplementation with up to 20 mg/day lutein on macular pigment optical density measured using heterochromatic flicker photometry and the mean increase in macular pigment optical density ranged from 0.025 to 0.09. It seems reason- able to conclude that the chance of eliciting an increase in macular pigment optical density during six months of daily supplementation with between 10 and 20 mg lutein that is of sufficient magnitude to be detected by using heterochromatic flicker photom- etry on an individual basis is small. Commercially available heterochromatic flicker photometers for macular pigment optical density assessment in the clinical environment appear to demonstrate particularly poor coefficient of repeatability values. Clinicians should exercise caution when considering the purchase of these instruments for poten- tial monitoring of macular pigment optical density in response to supplementation in individual patients. Submitted: 11 February 2010 Revised: 26 March 2010 Accepted for publication: 18 April 2010 Key words: heterochromatic flicker photometry, lutein, macular pigment, macular pigment optical density, zeaxanthin Yellow pigmentation of the macular region was first documented by Buzzi in 1782 but was attributed to the xanthophyll group of carotenoids by Wald in 1945. 1 Wald suggested that this yellow pigmenta- tion may filter out harmful blue and violet wavelengths that are not absorbed by the lens. 1 When the retinal carotenoids were separated using high-performance liquid chromatography in 1985, 2 two slightly different chemical structures were found and were termed lutein and zeaxanthin. CLINICAL AND EXPERIMENTAL OPTOMETRY Clinical and Experimental Optometry 93.5 September 2010 © 2010 The Authors 300 Clinical and Experimental Optometry © 2010 Optometrists Association Australia