Macular pigment density at the site of altered fundus autofluorescence

The purpose of our study was to determine whether abnormalities of increased or decreased fundus autofluorescence (FAF) are associated with local changes in macular pigment (MP) optical density in patients with age-related maculopathy (ARM) and macular degeneration (ARMD).

Simple and objective method for routine detection of the macular pigment xanthophyll

A new simple method for two-dimensional determination of optical density of macular pigment xanthophyll (ODx) in clinical routine is based on a single blue-reflection fundus image. Individual different vignetting is corrected by a shading function. For its construction, nodes are automatically found in structureless image regions. The influence of stray light in elderly crystalline lenses is compensated by a correction function that depends on age. The reproducibility of parameters in a one-wavelength reflection method determined for three subjects (47, 61, and 78 years old) was: maxODx = 6.3%, meanODx = 4.6%, volume = 6%, and area = 6% already before stray-light correction. ODx was comparable in pseudophakic and in an eye with a crystalline lens of the same 11 subjects after stray-light correction. Significant correlation in ODx was found between the one-wavelength reflection method and the two-wavelength autofluorescence method for pseudophakic and cataract eyes of 19 patients suffering from dry age-related macular degeneration (AMD) (R(2) = 0.855). In pseudophakic eyes, maxODx was significantly lower for dry AMD (n = 45) (ODx = 0.491±0.102 ODU) than in eyes with healthy fundus (n = 22) (ODx = 0.615±0.103 ODU) (p = 0.000033). Also in eyes with crystalline lens, maxODx was lower in AMD (n = 125) (ODx = 0.610±0.093 ODU) than in healthy subjects (n = 45) (ODx = 0.674±0.098 ODU) (p = 0.00019). No dependence on age was found in the pseudophakic eyes both of healthy subjects and AMD patients.

Association of macular pigment density with plasma ω-3 fatty acids: the PIMAVOSA study

To assess the correlation between macular pigment optical density and plasma levels of lutein, zeaxanthin, and fatty acids, especially omega-3 polyunsaturated fatty acids (PUFAs).

[Seasonal fluctuations and influence of nutrition on macular pigment density]

PURPOSE: We have previously reported on measuring macular pigment density (MPD) with a scanning laser ophthalmoscope (HRA, Heidelberg Engineering, Heidelberg, Germany). This study war undertaken to evaluate the variation of MPD over a period of 1 year in healthy subjects. METHOD: We used autofluorescence images recorded with a HRA to evaluate MPD with a 2 degrees circle centered on the fovea. Healthy subjects were included in the study and MPD measurements were repeated every 2 months over a period of 1 year. RESULTS: We included a total of 30 healthy subjects aged 19-34 years (mean: 23+/-2 years). Mean MPD at time point 1 was 0.215+/-0.056 density units (DU), at time point 2 0.235+/-0.051 DU, at time point 3 0.218+/-0.055 DU, at time point 4 0.228+/-0.057 DU, at time point 5 0.225+/-0.053 DU, and at time point 6 0.203+/-0.050 DU. The statistical analysis revealed no significant variation of MPD over the follow-up period of 1 year. CONCLUSION: This study demonstrates that MPD shows no variation over a period of 1 year in healthy subjects.

Ethnic differences in macular pigment density and distribution

PURPOSE: Many epidemiologic studies suggest a number of risk factors that may be associated with progression of age-related maculopathy (ARM). In this study, the authors investigate ethnic differences in macular pigment density (MPD) and macular pigment (MP) distribution. METHODS: Inclusion criteria were healthy subjects, aged 35 to 49 years, visual acuity >or=20/20, race ethnicity white non-Hispanic (WNH) or African. All subjects underwent the following examinations: best-corrected ETDRS visual acuity (VA), measurements of MPD, and spatial distribution of MP with a modified confocal scanning laser ophthalmoscope according to a standard protocol. MPD maps were calculated from autofluorescence images recorded at 488 nm and 514 nm. Central macular pigment density (MPDc) was quantified from MPD maps within 0.5 degrees around the center of the fovea. RESULTS: In total, 118 healthy subjects (61 women, 57 men) aged 35 to 49 years (mean, 42.5 +/- 3.6 years) were recruited for the study. Sixty-seven healthy subjects were WNH and 51 were African. Visual acuity ranged from 20/20 to 20/16 in the study eye. Significant differences were found among MPDc between the group of WNH (MPDc, 0.36 +/- 0.13 density units [DU]; P < 0.0001) and African subjects (MPDc, 0.59 +/- 0.14 DU). A parafoveal ring was significantly more frequent in African subjects than in WNH subjects (86% [African] vs. 68% [WNH]; P < 0.0001). CONCLUSIONS: This study demonstrates that ethnicity plays a role in MPD values and in MP distribution. The association of different distribution patterns and their relevance as possible prognostic factors for diseases leading to oxidative retinal damage requires further studies.

Oral Lutein Supplementation Enhances Macular Pigment Density and Contrast Sensitivity but Not in Combination With Polyunsaturated Fatty Acids.

Purpose It has been shown that lutein and zeaxanthin accumulate in the macula where they enhance contrast sensitivity and may reduce the risk of progression to advanced age-related macular degeneration (AMD). Furthermore, omega-3 long-chain polyunsaturated fatty acids (PUFA) might further reduce this risk. However, controversy exists regarding whether PUFA may reduce the bioavailability of lutein. Methods This was a prospective 12-month, randomized, open label study evaluating the effect of supplementation with lutein, other antioxidants, and minerals on contrast sensitivity (CS) and macular pigment optical density (MPOD) in patients with age-related maculopathy. A total of 79 patients were randomized to either lutein (10 mg) and antioxidant supplement or lutein and antioxidant supplement in combination with PUFA. Patients received supplementation for a period of 6 months and were followed for a total of 12 months. Results Serum lutein and zeaxanthin increased significantly by the first follow-up visit at 1 month, and remained elevated throughout the intervention period of 6 months in the lutein-only group but not in the lutein+PUFA group. Macular pigment optical density and CS increased significantly in the lutein-only group (P < 0.005) but not in the lutein+PUFA group (P = 0.059) compared to baseline. Best-corrected visual acuity remained unchanged during the entire study period in both groups. Conclusions Addition of PUFA may reduce the bioavailability of lutein and therefore lessen the beneficial effect on macular pigment and CS. This needs to be considered when prescribing lutein supplements to patients with low lutein levels. (ClinicalTrials.gov number, NCT00563979.).

Apparent motion photometry:evaluation and reliability of a novel method for the measurement of macular pigment

Background/aims Macular pigment is thought to protect the macula against exposure to light and oxidative stress, both of which may play a role in the development of age-related macular degeneration. The aim was to clinically evaluate a novel cathode-ray-tube-based method for measurement of macular pigment optical density (MPOD) known as apparent motion photometry (AMP). Methods The authors took repeat readings of MPOD centrally (0°) and at 3° eccentricity for 76 healthy subjects (mean (±SD) 26.5±13.2 years, range 18–74 years). Results The overall mean MPOD for the cohort was 0.50±0.24 at 0°, and 0.28±0.20 at 3° eccentricity; these values were significantly different (t=-8.905, p<0.001). The coefficients of repeatability were 0.60 and 0.48 for the 0 and 3° measurements respectively. Conclusions The data suggest that when the same operator is taking repeated 0° AMP MPOD readings over time, only changes of more than 0.60 units can be classed as clinically significant. In other words, AMP is not suitable for monitoring changes in MPOD over time, as increases of this magnitude would not be expected, even in response to dietary modification or nutritional supplementation.

Clinical evaluation of the MPS 9000 Macular Pigment Screener

Background/aims The MPS 9000 uses a psychophysical technique known as heterochromatic flicker photometry to measure macular pigment optical density (MPOD). Our aim was to determine the measurement variability (noise) of the MPS 9000. Methods Forty normally sighted participants who ranged in age from 18 to 50 years (25.4±8.2 years) were recruited from staff and students of Aston University (Birmingham, UK). Data were collected by two operators in two sessions separated by 1 week in order to assess test repeatability and reproducibility. Results The overall mean MPOD for the cohort was 0.35±0.14. There was no significant negative correlation between MPS 9000 MPOD readings and age (r=-0.192, p=0.236). Coefficients were 0.33 and 0.28 for repeatability, and 0.25 and 0.26 for reproducibility. There was no significant correlation between mean and difference MPOD values for any of the four pairs of results. Conclusions When MPOD is being monitored over time then any change less than 0.33 units should not be considered clinically significant as it is very likely to be due to measurement noise. The size of the coefficient appears to be positively correlated with MPOD.

Do lutein, zeaxanthin, and macular pigment optical density differ with age or age-related maculopathy?

Background and aims Current age-related macular disease (ARMD) treatment includes antioxidant supplementation. Lutein (L) and zeaxanthin (Z) are antioxidants that make up macularpigment within the retina and may reduce the risk of developing ARMD. Ageing and smoking are leading risk factors for developing ARMD. We investigated differences in dietary, supplemental and retinal L and Z, and smoking habits in healthy younger eyes (HY), healthy older eyes (HO) and eyes with an early form of ARMD called age-related maculopathy (ARM). Methods HO, HY and ARM groups were assessed for dietary intakes of L and Z using food diaries. Smoking habits and self-administered quantities of L and Z were obtained via questionnaire. Retinal L and Z levels (macularpigmentopticaldensity, or MPOD) were determined using heterochromatic flicker photometry. Results No significant difference was demonstrated for dietary L and Z intake (?2 = 4.983, p = 0.083) or for MPOD between groups (F = 0.40, p = 0.67). There was a significant difference between the HY (mean ± sd: 1.20 ± 2.99), HO (4.51 ± 7.05) ARM groups (9.15 ± 12.28) for pack years smoked (?2 = 11.61, p = 0.03). Conclusions Our results do not support the theory that ARM develops as a result of L and Z deficiency. Higher pack years smoked may be a factor in disease development. Dietary and supplementary L and Z levels must be obtained when assessing MPOD between groups or over time.

The role of macular pigment assessment in clinical practice:a review

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 investigated the repeatability of MPOD measurements using heterochromatic flicker photometry. 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 reasonable 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 photometry 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 potential monitoring of macular pigment optical density in response to supplementation in individual patients.

New investigations into macular pigment optical density

Macular pigment (MP) is the collective name for three carotenoids, lutein, zeaxanthin and meso-zeaxanthin, which are found at high concentrations in the central macula. The macular carotenoids, like all carotenoids, are entirely of dietary origin. The term ‘macular pigment optical density’ (MPOD) refers to the peak concentration of MP in the retina, which varies from one individual to the next and is measurable in vivo. On account of its blue-light-filtering and antioxidant properties, MP has become a subject of interest with respect to age-related macular degeneration (AMD), the hypothesis being that MP helps to protect against AMD; the higher the MPOD, the lower the risk for AMD. Recently, a new MPOD-measuring device, the MPS 9000 (MPS), entered the ophthalmic market. Using this device, the research described here aimed to contribute new information to the MP literature. A second MPOD instrument, the Macular Pigment Reflectometer, was also used at times, but a reliability study (included in the thesis) demonstrated that it was unsuitable for use on its own. First, a series of exploratory investigations were undertaken to maximize the accuracy and consistency of MPOD measurements taken with the MPS; a protocol was established that substantially improved repeatability. Subsequently, a series of MPOD-based studies were conducted on anisometropia, South Asian race, blue-light-filtering contact lenses, and dietary modification with kale. The principle findings were as follows: interocular MPOD differences were not attributable to interocular refractive error differences; young adults of South Asian origin had significant gender-related MPOD differences (males>females, p<0.01), and they also had significantly higher MPOD than Caucasians (p<0.0005); wearing blue-light-filtering contact lenses for eight months did not affect MPOD; and dietary modification with kale for 16 weeks did not increase MPOD. This body of research adds new insights to MP knowledge, which in turn may contribute to MP knowledge in the context of AMD.

Macular pigment optical density is related to blood glutathione levels in healthy individuals

Purpose. To assess the relationship between macular pigment optical density (MPOD) and blood markers for antioxidant defense in otherwise healthy volunteers. Methods. Forty-seven healthy volunteers were subjected to blood analysis to detect the level of circulating glutathione in its reduced (GSH) and oxidized (GSSG) forms. The level of MPOD was measured using heterochromatic flicker photometry. Systemic blood pressure (BP) parameters, heart rate (HR), body mass index (BMI), and plasma levels of total, HDL, and LDL cholesterol and triglycerides (TGs) were also determined. Results. A simple correlation model revealed that the level of MPOD correlated significantly and positively with both GSH (P < 0.001) and t-GSH (P < 0.001) levels but not with those of GSSG (P > 0.05). Age, sex, systemic BP parameters, HR, BMI, and plasma levels of cholesterol and TGs did not have any influence on either MPOD or glutathione levels (all P > 0.05). In addition, a forward stepwise multiple regression analysis showed MPOD to have a significantly and independent correlation with GSH levels (ß = 0.63; P < 0.001). Conclusions. In otherwise healthy older individuals, there is a positive correlation between local and systemic antioxidant defense mechanisms.

Clinical evaluation of the Macuscope macular pigment densitometer

Background/aims. The MacuScope uses a psychophysical technique called heterochromic flicker photometry to measure macular pigment optical density (MPOD). Our aim was to determine the measurement variability (noise) of the MacuScope. Methods. Thirty-eight normally sighted participants who ranged in age from 19 to 46 years (25.7±7.6 years) were recruited from staff and students of Aston University. Data were collected by two operators, HB and JA, in two sessions separated by 1 week in order to assess test repeatability and reproducibility. Results. The overall mean MPOD for the cohort was 0.47±0.14. There was a significant negative correlation between MacuScope MPOD readings and age (r=-0.368, p=0.023). Coefficients were 0.45 and 0.58 for repeatability, and 0.49 and 0.36 for reproducibility. For each pair of results, there was a significant positive correlation between mean and difference MPOD values. Conclusions. If MPOD is being monitored over time then any change less than 0.58 units should not be considered clinically significant as it is very likely to be due to instrument noise. The size of the coefficient appears to be positively correlated with MPOD.