Effect of Cataract in Evaluation of Macular Pigment Optical Density by Autofluorescence Spectrometry

Effect of Antioxidant Supplementation on Macular Pigment Optical Density and Visual Functions: A Systematic Review and Network Meta-Analysis of Randomized Controlled Trials

Antioxidants are bioactive molecules that function to scavenge free radicals and balance oxidative stress. Although all antioxidants can act as reactive oxygen species scavengers, their efficacy on eye health may vary. Moreover, the comparative effectiveness and potential additive effect between groups of antioxidants, hitherto, have not been systematically studied. A systematic review and network meta-analysis were conducted to investigate the comparative or additive effect of dietary antioxidant supplements on eye health. Four databases (PubMed, Embase, CINAHL, and Cochrane) were searched, and relevant randomized controlled trials were identified. Out of 60 articles selected for systematic review, 38 were included in the network meta-analysis, categorized into 8 distinct antioxidant-supplemented groups and placebo. All groups significantly increased macular pigment optical density and contrast sensitivity at low spatial frequency, whereas only the antioxidant mixture + lutein (L) + fatty acid combination exhibited significant improvements in visual acuity (hazard ratio = -0.15; 95% confidence interval: -0.28, -0.02) and L + zeaxanthin combination for photostress recovery time (hazard ratio = -5.75; 95% confidence interval: -8.80, -1.70). Especially, the L + zeaxanthin + fatty acid combination was ranked best for macular pigment optical density (surface under the cumulative ranking: 99.3%) and second best for contrast sensitivity at low spatial frequency (67.7%). However, these findings should be interpreted with caution due to low quality of evidence, primarily influenced by indirectness and potential publication bias. Overall, antioxidant supplementation was estimated to improve eye health parameters, whereas different combinations of antioxidants may also have varying effects on improving visual health from multiple perspectives. This study was registered at PROSPERO as CRD42022369250.

New technology using crystalline lens autofluorescence for presbyopia and cataract grading

PURPOSE

To investigate  whether fundus autofluorescence (FAF) obtained using an ultra-wide field (UWF) fundus camera with an artificial opacity pattern can grade the degree of presbyopia and nuclear cataract.

METHODS

Sixty eyes of 30 patients were enrolled in this prospective diagnostic study. The nuclear cataract (nuclear color/opalescence (NC/NO)) was graded according to the Lens Opacity Classification System III. The monocular near point of accommodation (NPA) was measured in eyes with NC3/NO3 or less. The mean gray value difference between the central 8 artificial opacity lesions and peripheral 8 artificial opacity lesions in the retinal AF was measured. The correlation between the mean gray value difference, NPA, and nuclear cataract grade was analyzed.

RESULTS

The mean nuclear cataract grade of 60 eyes was 3.2 ± 1.6 and mean NPA of 37 eyes was 45.3 ± 16.1 cm. The mean gray value differences increased with increasing nuclear cataract grade (eyes with NC/NO grade 1, 53.3 ± 11.4; 2, 78.3 ± 13.6; 3, 95.2 ± 12.2; 4, 101.6 ± 11.9; 5, 109.0 ± 22.9; and 6, 121.1 ± 12.0; p < 0.001). The mean gray value difference was positively correlated with both the monocular NPA (R² = 0.637; β coefficient = 1.009; 95% CI, 0.748 to 1.271; p < 0.001) and nuclear cataract grade (R² = 0.661; β coefficient = 12.437; 95% CI, 10.097 to 14.778; p < 0.001).

CONCLUSIONS

The FAF camera with an artificial opacity pattern attached can be used to effectively diagnose the degree of presbyopia and nuclear cataract.

Macular pigment optical density and its determinants in a Russian population: the ural eye and medical study

PURPOSE

To assess the macular pigment optical density (MPOD) and its associations with ocular and systemic parameters and diseases.

METHODS

The population-based study Ural Eye and Medical Study included 5899 (80.5%) out of 7328 eligible individuals. As part of ophthalmological and systemic examinations, MPOD was measured by reflectometry.

RESULTS

Macular pigment optical density (MPOD) data were available for 4889 (82.9%) individuals (mean age:57.8 ± 10.1 years;range: 40-94). Mean values for MOPD, maximal MOPD, macular pigment (MP) area and MP volume were 0.13 ± 0.04 d.u. (density units), 0.36 ± 0.09 d.u., 60 791 ± 14 826 pixel and 8033 ± 2888 d.u.pixel, respectively. A higher MP density was correlated (regression coefficient r: 0.63) with older age (standardized regression coefficient beta: 0.59; non-standardized regression coefficient B: 0.23; 95% confidence interval (CI): 0.22, 0.23; p < 0.001), female sex (beta: 0.08; B:0.63; 95%CI: 0.44, 0.83; p < 0.001), rural region of habitation (beta: 0.13; B: 1.02; 95%CI: 0.83, 1.22; p < 0.001), lower body mass index (beta: -0.04; B: -0.03; 95%CI: -0.05, 0.01; p = 0.004), lower prevalence of chronic obstructive pulmonary disorder (beta: -0.03; B: -0.43; 95%CI: -0.79, -0.08; p = 0.02), higher erythrocyte sedimentation rate (beta: 0.03; B: 0.01; 95%CI: 0.002, 0.02; p = 0.03), lower leukocyte cell count (beta: -0.04; B: -0.10; 95%CI: -0.16, -0.03; p = 0.003), thinner temporal parafoveal retinal thickness (beta: -0.06; B: -0.01;95%CI: -0.01, -0.003; p < 0.001), thinner central corneal thickness (beta: -0.06; B: -0.006; 95%CI: -0.009, -0.004; p < 0.001), higher prevalence of pseudophakia (beta: 0.09;B:2.08; 95%CI: 1.50, 2.65; p < 0.001) and reticular pseudo drusen (RPD) (beta: 0.03; B: 0.56; 95%CI: 0.13, 0.98; p = 0.01) and lower stage of open-angle glaucoma (beta: -0.03; B: -0.39; 95%CI: -0.74, -0.04; p = 0. 03). Prevalence (p = 0.44; beta: -0.01) and degree (p = 0.70; beta: -0.01) of angle-closure glaucoma, prevalence (p = 0.31; beta: 0.01) of age-related macular degeneration (AMD) without RPD and prevalence (p = 0.95; beta: 0.001) of diabetic retinopathy were not significantly associated with the mean MP density in that model.

CONCLUSIONS

A higher RPD prevalence and lower stage of open-angle glaucoma were ophthalmological disorders associated with a higher MPOD in a multivariable analysis, including parameters of older age, pseudophakia, female sex, rural region, lower body mass index and lower perifoveal retinal thickness.

Macular Pigment and Open-Angle Glaucoma in the Elderly: The Montrachet Population-Based Study

(1) Background: To compare macular pigment optical density (MPOD) and its spatial distribution between eyes with primary open-angle glaucoma (POAG) and control eyes in an elderly population. (2) Methods: The Montrachet study (Maculopathy Optic Nerve and nutrition neurovAsCular and HEarT) is a population-based study including participants aged 75 years and over. All participants had a slit lamp examination, fundus photographs, and a questionnaire about their medical past history and smoking status. Optic disc spectral domain optical coherence tomography was also performed. All glaucoma-suspected patients were convocated to have a new full examination. We only retained one eye with POAG for analysis in the glaucoma group and one eye without optic neuropathy in the control participants group. MPOD measurements were performed with the two-wavelength autofluorescence method (488 and 514 nm). (3) Results: Overall, 601 eyes had MPOD measurements among 1153 participants. Among the 601 eyes, 48 had POAG. The mean age for the glaucoma and control participants was 84.01 ± 4.22 years and 81.94 ± 3.61 years, respectively (p < 0.001). In the multivariable analysis, we could not find any association between POAG and MPOD at 0.5° (p = 0.336). We found no significant difference regarding MP spatial distribution between the two groups (p = 0.408). (4) Conclusion: In this elderly population-based study, eyes with POAG and control eyes without optic neuropathy did not differ in terms of MPOD and MP spatial distribution.

Influence of lens opacities and cataract severity on quantitative fundus autofluorescence as a secondary outcome of a randomized clinical trial

The aim of this study is to investigate the impact of age-related lens opacities and advanced cataract, quantified by LOCS III grading, on quantitative autofluorescence (qAF) measurements in patients before and after cataract surgery. Images from a randomized controlled trial evaluating the impact of femtosecond-laser assisted cataract surgery (FLACS) on retinal thickness were analyzed post-hoc. One-hundred and twenty eyes from 60 consecutive patients with age-related cataract were included and assessed with qAF and optical coherence tomography (OCT) before, 1, 3 and 6 weeks after cataract surgery (randomized 1:1 to FLACS or phacoemulsification). LOCS III grading was performed before surgery. Pre- to post-surgical qAF values, as well as the impact of LOCS III gradings, surgery technique, gender, axial length and age on post-surgery qAF values was investigated using generalized linear mixed models. For this analysis, 106 eyes from 53 patients were usable. No difference in qAF was found between FLACS and phacoemulsification (p > 0.05) and results were pooled for the total cohort. Mean pre-surgical qAF was 89.45 ± 44.9 qAF units, with a significant mean increase of 178.4–191.6% after surgery (p < 0.001). No significant difference was found between the three follow-up visits after surgery (p > 0.05). Higher LOCS III cortical opacity quantifications were associated with a significantly greater increase in qAF after surgery (estimate: 98.56, p = 0.006) and nuclear opacities showed a trend toward an increased change (estimate: 48.8, p = 0.095). Considerable interactions were identified between baseline qAF and cortical opacities, nuclear opacities and posterior subcapsular opacities, as well as nuclear opacities and cortical opacities (p = 0.012, p = 0.064 and p = 0.069, respectively). Quantitative autofluorescence signals are significantly reconstituted after cataract surgery and LOCS III gradings are well associated with post-surgical qAF values. Careful consideration of age-related lens opacities is vital for the correct interpretation of qAF, especially in retinal diseases affecting the elderly.

ClinicalTrials.gov Identifier: NCT03465124.

Spatial distribution of macular pigment estimated by autofluorescence imaging in elderly Japanese individuals

PURPOSE

To determine the spatial distribution types of macular pigment (MP) in elderly Japanese individuals and to consider their origin.

STUDY DESIGN

Observational case series.

METHODS

Local MP optical density (MPOD) at some eccentricities and MP volume were measured using the MPOD module of a MultiColor Spectralis in 96 pseudophakic eyes of 96 participants (age range, 52-86 years; mean age, 72.8 ± 8.3 years). The MP distribution types were determined from the MP spatial profiles. The retinal thickness (RT) at the foveal center, at both 0.5° and 0.9° eccentricities, and the foveal width were measured using optical coherence tomography.

RESULTS

The mean local MPOD at the foveal center was 0.79. Spatial distribution was classified into four types: central peak (24.0%), ring-like (40.6%), intermediate (22.9%), and central dip (12.5%). The ring-like type was the most frequent in these Japanese participants. The central-peak type showed lower MPOD than did the other types in the area outside 0.9°. The ring-like type occurred frequently in eyes with small RT at 0.5° and wider foveal width. A rough contour of the Müller cell cone was found more frequently in the central-dip type than in the other types.

CONCLUSIONS

The present characteristics of the different distribution patterns could be explained by the hypothesis that MP presents mainly in the Müller cell cone within 0.5° and in Müller cells in the outer and inner plexiform layers in the area outside 0.5°. The anatomic characteristics of Müller cells at the fovea and parafovea likely affect the MP distribution.

Grade of Cataract and Its Influence on Measurement of Macular Pigment Optical Density Using Autofluorescence Imaging

Purpose

To evaluate the influence of cataracts on measuring macular pigment optical density (MPOD) using a dual-wavelength confocal scanning autofluorescence imaging technique and to establish methods to compensate for the influence of cataracts.

Methods

This prospective case series comprised 100 eyes that underwent cataract surgery. Cataracts were graded based on the World Health Organization classification. MPOD levels were measured with the MPOD module of the Spectralis MultiColor instrument (Spectralis-MP), pre- and postoperatively. We investigated the relationship between change in MPOD values and age, cataract grade, and quality of autofluorescence images. Local MPOD levels were evaluated for four strategically chosen eccentricities within the macular region, and the total MPOD volume was evaluated within 8.98° eccentricity from the center.

Results

MPOD levels could be obtained in 67 eyes before surgery. Local and volume MPOD levels were higher postoperatively relative to preoperatively in all eyes. The mean ratio of local MPOD levels after and before surgery (correction factor, CF) ranged from 1.42 to 1.77, with larger CFs required for eccentricities closer to the foveal center. The CF for the MPOD volume was 1.31. Age, grade of nuclear cataract (NUC), posterior subcapsular opacity, and image quality index (IQI) significantly contributed to CFs. For example, regression equation for CF at 0.23° = 0.17 + 0.16 × IQI + 0.29 × NUC grade + 0.01 × age (P < 0.001).

Conclusions

Cataracts affected MPOD measurements with the Spectralis-MP, but corrected MPOD results could be obtained via regression equations.

Changes in macular pigment optical density after membrane peeling

Introduction

To highlight the differences in macular pigment optical density (MPOD) between eyes with vitreoretinal interface syndrome and healthy control eyes, to assess the changes in MPOD in eyes treated with macular peeling, to investigate the relationships between MPOD changes and measures of retinal sensitivity such as best corrected visual acuity (BCVA) and microperimetry.

Methods

In this cross-sectional comparative study, 30 eyes affected by idiopathic epiretinal membrane (iERM, 15eyes) or full-thickness macular hole (FTMH, 15eyes) were compared with 60 eyes from 30 healthy age-matched patients. MPOD values (mean MPOD, maximum MPOD, MPOD area, and MPOD volume) were measured in a range of 4°–7° of eccentricity around the fovea, using the one-wavelength reflectometry method (Visucam 200, Carl-Zeiss Meditec). Patients affected by iERM and FTMH were treated with vitrectomy and epiretinal membrane-inner limiting membrane (ERM-ILM) peeling, with follow-up examinations performed preoperatively and 6 months postoperatively. The main outcome measures were the differences in MPOD between eyes with vitreoretinal interface syndrome and healthy eyes, changes in MPOD after ERM-ILM peeling, and relationships between MPOD and functional changes.

Results

Mean MPOD differed significantly between control eyes and those with iERM (P = .0001) or FTMH (P = .0006). The max MPOD and MPOD area increased, but not significantly. After peeling, the only significant change in MPOD was in MPOD volume (P = .01). In the ERM group, postoperative mean MPOD correlated significantly with best-corrected visual acuity (r = .739, P = .002).

Conclusions

MPOD was reduced in patients with iERM or FTMH compared with healthy eyes. We found a significant correlation between the mean postoperative MPOD and postoperative BCVA, hypothesizing that the postoperative increase in mean MPOD could be due to a change in distribution for unfolding and expansion of the fovea after the peeling. MOPD may be considered as a prognostic factor associated with a good visual prognosis in patients with iERM.

Absolute and estimated values of macular pigment optical density in young and aged Asian participants with or without age-related macular degeneration

Background

Lutein and zeaxanthin are suggested micronutrient supplements to prevent the progression of age-related macular degeneration (AMD), a leading cause of blindness worldwide. To monitor the levels of lutein/zeaxanthin in the macula, macular pigment optical density (MPOD) is measured. A commercially available device (MPSII®, Elektron Technology, Switzerland), using technology based on heterochromatic flicker photometry, can measure both absolute and estimated values of MPOD. However, whether the estimated value is applicable to Asian individuals and/or AMD patients remains to be determined.

Methods

The absolute and estimated values of MPOD were measured using the MPSII® device in 77 participants with a best-corrected visual acuity (BCVA) > 0.099 (logMAR score).

Results

The studied eyes included 17 young (20–29 years) healthy, 26 aged (>50 years) healthy, 18 aged and AMD-fellow, and 16 aged AMD eyes. The mean BCVA among the groups were not significantly different. Both absolute and estimated values were measurable in all eyes of young healthy group. However, absolute values were measurable in only 57.7%, 66.7%, and 43.8%, of the aged healthy, AMD-fellow, and AMD groups, respectively, and 56.7% of the eyes included in the 3 aged groups. In contrast, the estimated value was measurable in 84.6%, 88.9% and 93.8% of the groups, respectively, and 88.3% of eyes in the pooled aged group. The estimated value was correlated with absolute value in individuals from all groups by Spearman’s correlation coefficient analyses (young healthy: R² = 0.885, P = 0.0001; aged healthy: R² = 0.765, P = 0.001; AMD-fellow: R² = 0.851, P = 0.0001; and AMD: R² = 0.860, P = 0.013). Using the estimated value, significantly lower MPOD values were found in aged AMD-related eyes, which included both AMD-fellow and AMD eyes, compared with aged healthy eyes by Student’s t-test (P = 0.02).

Conclusions

Absolute, in contrast to estimated, value was measurable in a limited number of aged participants; however, it was correlated with estimated value both in young and aged Asian populations with or without AMD. These results may inform future clinical studies investigating the measurement of MPOD in understanding the role of macular pigments in the pathogenesis of AMD.

Correlations Between Macular, Skin, and Serum Carotenoids

Purpose

Ocular and systemic measurement and imaging of the macular carotenoids lutein and zeaxanthin have been employed extensively as potential biomarkers of AMD risk. In this study, we systematically compare dual wavelength retinal autofluorescence imaging (AFI) of macular pigment with skin resonance Raman spectroscopy (RRS) and serum carotenoid levels in a clinic-based population.

Methods

Eighty-eight patients were recruited from retina and general ophthalmology practices from a tertiary referral center and excluded only if they did not have all three modalities tested, had a diagnosis of macular telangiectasia (MacTel) or Stargardt disease, or had poor AFI image quality. Skin, macular, and serum carotenoid levels were measured by RRS, AFI, and HPLC, respectively.

Results

Skin RRS measurements and serum zeaxanthin concentrations correlated most strongly with AFI macular pigment volume under the curve (MPVUC) measurements up to 9° eccentricity relative to MPVUC or rotationally averaged macular pigment optical density (MPOD) measurements at smaller eccentricities. These measurements were reproducible and not significantly affected by cataracts. We also found that these techniques could readily identify subjects taking oral carotenoid-containing supplements.

Conclusions

Larger macular pigment volume AFI and skin RRS measurements are noninvasive, objective, and reliable methods to assess ocular and systemic carotenoid levels. They are an attractive alternative to psychophysical and optical methods that measure MPOD at a limited number of eccentricities. Consequently, skin RRS and MPVUC at 9° are both reasonable biomarkers of macular carotenoid status that could be readily adapted to research and clinical settings.

Clinical applications of fundus autofluorescence in retinal disease

Fundus autofluorescence (FAF) is a non-invasive retinal imaging modality used in clinical practice to provide a density map of lipofuscin, the predominant ocular fluorophore, in the retinal pigment epithelium. Multiple commercially available imaging systems, including the fundus camera, the confocal scanning laser ophthalmoscope, and the ultra-widefield imaging device, are available to the clinician. Each offers unique advantages for evaluating various retinal diseases. The clinical applications of FAF continue to expand. It is now an essential tool for evaluating age related macular degeneration, macular dystrophies, retinitis pigmentosa, white dot syndromes, retinal drug toxicities, and various other retinal disorders. FAF may detect abnormalities beyond those detected on funduscopic exam, fluorescein angiography, or optical coherence tomography, and can be used to elucidate disease pathogenesis, form genotype-phenotype correlations, diagnose and monitor disease, and evaluate novel therapies. Given its ease of use, non-invasive nature, and value in characterizing retinal disease, FAF enjoys increasing clinical relevance. This review summarizes common ocular fluorophores, imaging modalities, and FAF findings for a wide spectrum of retinal disorders.

Autofluorescence imaging of macular pigment: influence and correction of ocular media opacities

The healthy adult human retina contains in its macular region a high concentration of blue-light absorbing carotenoid compounds, known as macular pigment (MP). Consisting of the carotenoids lutein, zeaxanthin, and meso-zeaxanthin, the MP is thought to shield the vulnerable tissue layers in the retina from lightinduced damage through its function as an optical attenuator and to protect the tissue cells within its immediate vicinity through its function as a potent antioxidant. Autofluorescence imaging (AFI) is emerging as a viable optical method for MP screening of large subject populations, for tracking of MP changes over time, and for monitoring MP uptake in response to dietary supplementation. To investigate the influence of ocular media opacities on AFI-based MP measurements, in particular, the influence of lens cataracts, we conducted a clinical trial with a large subject population (93 subjects) measured before and after cataract surgery. General AFI image contrast, retinal blood vessel contrast, and presurgery lens opacity scores [Lens Opacities Classification System III (LOCS III)] were investigated as potential predictors for image degradation. These clinical results show that lens cataracts can severely degrade the achievable pixel contrasts in the AFI images, which results in nominal MP optical density levels that are artifactually reduced. While LOCS III scores and blood vessel contrast are found to be only a weak predictor for this effect, a strong correlation exists between the reduction factor and the image contrast, which can be quantified via pixel intensity histogram parameters. Choosing the base width of the histogram, the presence or absence of ocular media opacities can be determined and, if needed, the nominal MP levels can be corrected with factors depending on the strength of the opacity.

Macular pigment optical density measurements by one-wavelength reflection photometry--influence of cataract surgery on the measurement results

PURPOSE

The main objective of the present study was the investigation of possible influence of lens opacification on macular pigment optical density (MPOD) measurements.

METHODS

Eighty-six eyes of 64 patients (mean age 73.4 ± 8.3 years) were included in the study. MPOD was prospectively measured using the one-wavelength reflection method (Visucam500, Carl Zeiss Meditec AG) before and after cataract extraction, with implantation of a blue-light filtering intraocular lens (AlconSN60WF). The median of the maximum optical density (MaxOD) and the median of the mean optical density (MeanOD) measurements of macular pigment across the subject group were evaluated.

RESULTS

Statistically significant differences were noticed between pre-operative and post-operative measurements, the absolute values were generally lower after cataract extraction. The following median (lower/upper quartile) differences across the group were determined: MaxOD -33.8 % (-46.2 to -19.1 %), MeanOD -44.0 % (-54.6 to -26.6 %). Larger changes were observed in elderly patients [<70 years of age (n = 25 eyes): MaxOD -13.4 % (-20.5 to 3.6 %), MeanOD -23.6 % (-30.5 to -15.3 %) versus patients ≥70 years (n = 61 eyes) MaxOD -40.5 % (-53.2 to -30.1 %), MeanOD -47.2 % (-57.8 to -40.1 %)] and in patients with progressed stage of cataract. MaxOD for lens opacification grade 1 (n = 9 eyes): -27.4 % (-42.1 to -19.6 %), grade 2 (n = 26 eyes): -35.0 % (-44.2 to -25.3 %), grade 3 (n = 21 eyes): -34.4 % (-45.4 to -11.4 %), grade 4 (n = 25 eyes): -32.6 % (-53.2 to -6.4 %), and grade 5 (n = 5 eyes): -53.5 % (-61.7 to -38.7 %) and MeanOD for cataract stage 1 (n = 9 eyes): -42.6 % (-46.0 to -26.0 %), stage 2 (n = 26 eyes): -44.1 % (-51.8 to -26.2 %), stage 3 (n = 21 eyes): -45.7 % (-54.7 to -24.7 %), stage 4 (n = 25 eyes): -39.5 % (-59.4 to -26.1 %), and stage 5 (n = 5 eyes): -57.0 % (-66.1 to -51.4 %).

CONCLUSIONS

As established by comparison of pre- to post-operative measurements, cataract presented a strong effect on MPOD measured by one-wavelength reflection method. Particular care should therefore be taken when evaluating MPOD using this method in elderly patients with progressed stage of cataract. Future optimization of correcting parameters of scattered light and consideration of cataract influence may allow more precise evaluation of MPOD.

The heritability of the ring-like distribution of macular pigment assessed in a twin study

PURPOSE

It has been suggested that ring-like patterns of macular pigment, as measured with dual wavelength autofluorescence, are observed less frequently in subjects with age-related maculopathy. We explored relative contributions of genetic and environmental factors in macular pigment optical density (MPOD) distributions using a classic twin study.

METHODS

As part of a previous nutritional study, 322 healthy Caucasian female twins, aged 16 to 50 (mean 40) years, underwent measurement of MPOD optical density by two-wavelength fundus autofluorescence. In the present study, the right eye MPOD profile was assessed for the presence of a ring-like pattern by two graders independently, using common criteria, with a third grader arbitrating in cases of disagreement. Concordance was calculated as 2C/(2C + D), where C is the number of twin pairs concordant, and D the number discordant, for the ring-like pattern. Also, heritability was calculated using maximum-likelihood structural equation modeling.

RESULTS

Images and zygosity data were available for 314 twins (88 monozygotic [MZ] and 69 dizygotic [DZ] pairs). The overall prevalence of the ring pattern was 25.8%. Respective concordances for MZ and DZ twins were 0.75 and 0.22. Additive genetic factors were estimated to contribute to 84.0% of the total variance (95% confidence intervals, 63.7%-94.6%).

CONCLUSIONS

Concordance for MZ twins was over three times that for DZ twins, with heritability estimated at 84%, indicating that genetic factors contribute to the development of the ring structure. Studies have suggested that ring-like patterns of macular pigment can affect risk for age-related maculopathy. In a classic twin study, we found that the presence of such a pattern was highly heritable.

Macular pigment imaging in AREDS2 participants: an ancillary study of AREDS2 subjects enrolled at the Moran Eye Center

PURPOSE

Age-Related Eye Disease Study 2 (AREDS2) is a randomized, placebo-controlled study designed to determine whether supplementation with 10 mg of lutein and 2 mg of zeaxanthin per day can slow the rate of progression of age-related macular degeneration (AMD). Although some biomarkers of response to carotenoid supplementation such as serum concentrations are part of the AREDS2 protocol, measurement of carotenoid concentrations in the eye and other tissues is not. In this approved ancillary study, macular pigment optical density (MPOD), macular pigment distributions, and skin carotenoid levels at enrollment and at each annual visit were measured to assess baseline carotenoid status and to monitor response to assigned interventions.

METHODS

All subjects enrolled at the Moran Eye Center had MPOD and macular pigment spatial distributions measured by dual-wavelength autofluorescence imaging and total skin carotenoids measured by resonance Raman spectroscopy. Results. Baseline MPOD in enrolled subjects was unusually high relative to an age-matched control group that did not consume carotenoid supplements regularly, consistent with the high rate of habitual lutein and zeaxanthin consumption in Utah AREDS2 subjects prior to enrollment. MPOD did not correlate with serum or skin carotenoid measurements.

CONCLUSIONS

Useful information is provided through this ancillary study on the ocular carotenoid status of AREDS2 participants in the target tissue of lutein and zeaxanthin supplementation: The macula. When treatment assignments are unmasked at the conclusion of the study, unique tissue-based insights will be provided on the progression of AMD in response to long-term, high-dose carotenoid supplementation versus diet alone. (ClinicalTrials.gov number, NCT00345176.).

Comparison of macular pigment in patients with age-related macular degeneration and healthy control subjects - a study using spectral fundus reflectance

PURPOSE

Previous studies have reported an age-dependent decline of macular pigment optical density (MPOD) as well as a relative lack of MPOD in age-related macular degeneration (AMD). Results are, however, strongly dependent on the technique used. In this study, we investigated the age dependence of MPOD using spectral fundus reflectance. In addition, we hypothesized that patients with AMD have a reduced MPOD as compared to healthy controls.

METHODS

A total of 85 healthy subjects and 96 patients with AMD were included in this study. The healthy control subjects showed a wide range of ages (mean, 51.6 years; range, 21-79years). Patients with AMD were significantly older (mean, 71.2 years; range, 50-89 years). Spectral fundus reflectance of the fovea was measured in a 2.3° detection field with a custom built fundus reflectometer. Calculation of MPOD was based on a previously published fundus reflectance model.

RESULTS

Patients with AMD showed a reduced MPOD (0.35 ± 0.12) as compared to the healthy control group (0.39 ± 0.12, p = 0.013 between groups). No age dependence of MPOD (r = -0.14, p = 0.19) was found in the healthy control group. In the AMD group, however, MPOD declined with age (r = -0.24, p = 0.019).

CONCLUSIONS

This study indicates that MPOD is reduced in patients with AMD. In addition, the data of this study indicate that MPOD is age dependent in AMD patients, but not in healthy controls. Taken together with data indicating that lutein supplementation increases MPOD, this provides a rationale for supplementation of the macular pigments in patients with AMD, although long-term clinical outcome data are lacking.

Heritability of the spatial distribution and peak density of macular pigment: a classical twin study

PURPOSE

To elucidate the heritability of peak density and spatial width of macular pigment (MP) using a Classical Twin Study.

METHODS

Fundus autofluorescence images were obtained at 488 nm from 86 subjects or 43 twin pairs (21 monozygotic (MZ) and 22 dizygotic (DZ)) (27 male, 59 female) aged from 55 to 76 years (mean 62.2 ± 5.3 years). The relative topographic distribution of MP was measured using a grey scale of intensity (0-255 units) in a 7° eccentricity around the fovea. Relative peak MP density (rPMPD) and relative spatial distribution of MP (rSDMP) were used as the main outcome measure in the statistical analysis.

RESULTS

A significantly higher correlation was found within MZ pairs as compared with that within DZ pairs for rPMPD, (r=0.99, 95% confidence interval (95% CI) 0.93 to 1.00) and 0.22, 95% CI -0.34 to 0.71), respectively, suggesting strong heritability of this trait. When rSDMP was compared, there was no significant difference between the correlations within MZ pairs (r=0.48, 95% CI -0.02 to 0.83) and DZ pairs (r=0.63, 95% CI 0.32 to 0.83), thus rSDMP is unlikely to have a considerable heritable component. In addition, there was no difference between any MP parameter when normal maculae were compared with early age-related macular degeneration (AMD) (rPMPD 0.36 vs 0.34, t=1.18 P=0.243, rSDMP 1.75 vs 1.75, t=0.028 P=0.977).

CONCLUSIONS

rPMPD is a strongly heritable trait whereas rSDMP has minimal genetic influence and a greater influence by environmental factors. The presence of macular changes associated with early AMD did not appear to influence any of these pigment parameters.

Two-wavelength fundus autofluorescence and macular pigment optical density imaging in diabetic macular oedema

PURPOSE

To evaluate the application of 488 and 514 nm fundus autofluorescence (FAF) and macular pigment optical density (MPOD) imaging in diabetic macular oedema (DMO) and to demonstrate the typical imaging features.

PATIENTS AND METHODS

A hundred and twenty-five eyes of 71 consecutive patients with diabetic retinopathy who underwent examination at a specialist university clinic employing a modified Heidelberg Retina Angiograph, using two different light sources of 488 and 514 nm wavelength, were retrospectively reviewed. MPOD images were calculated using modified Heidelberg Eye Explorer software. All images were evaluated by two independent masked graders. Features from FAF and MPOD images were correlated with optical coherence tomography (OCT) imaging findings and inter-grader variability, sensitivity and specificity were calculated using OCT as reference.

RESULTS

Sixty-seven eyes had DMO on OCT. The inter-grader variability was 0.84 for 488 nm FAF, 0.63 for 514 nm FAF and 0.79 for MPOD imaging. Sensitivity and specificity for detection of DMO were 80.6 and 89.7% for 488 nm FAF; 55.2 and 94.8% for 514 nm FAF; and 80.6 and 91.4% for MPOD imaging. In 488 nm FAF and MPOD imaging, DMO was better visualised in comparison with 514 nm FAF imaging, P<0.01. MPOD revealed displacement of macular pigment by intraretinal cysts.

CONCLUSION

MPOD imaging, and particularly its combination with 488 nm and 514 nm FAF, provides a valuable addition to OCT in the evaluation of DMO and is clinically useful in rapid en-face assessment of the central macula.

Short- and mid-term repeatability of macular pigment optical density measurements using spectral fundus reflectance

BACKGROUND

Several methods have been proposed for measuring macular pigment optical density (MPOD). To date, none of the realized techniques can be considered as "gold standard". A key issue for the clinical applicability of a method is its repeatability. In this study, we investigated short- and mid-term repeatability of MPOD measurements using reflectometry.

METHODS

A total of 12 healthy young subjects were measured 5 times on 5 consecutive days. Repeatability over 6 months was investigated in patients with AMD. The data in AMD patients were taken from a recently published placebo controlled study investigating the effect of lutein supplementation on MPOD (n = 37; [1]). Four measurements over 6 months were used to calculate repeatability. Spectral fundus reflectance of the fovea was measured in a 2.3° detection field with a custom-built fundus reflectometer. Calculation of MPOD was based on a previously published fundus reflectance model.

RESULTS

The coefficients of variation were 6.2 ± 2.4% and 8.0 ± 5.5% in the healthy and AMD group, respectively. Bland-Altman plots indicate that the difference between measurements at day 1 and day 5 in healthy subjects and day 1 and month 6 in AMD patients was small. The maximum deviation in MPOD in a healthy subject was 0.07 (22.6%), and 0.17 (51.5%) in a patient with AMD.

CONCLUSIONS

Reflectometry provides adequate short-term and mid-term repeatability for measuring MPOD. Accordingly, the technique makes it possible to monitor MPOD in patients with AMD and to study the influence of supplementation in these subjects. In addition, the variability of the technique is small enough to allow for clinical trials with reasonable sample size.

Randomized, double-blind, placebo-controlled study of zeaxanthin and visual function in patients with atrophic age-related macular degeneration: the Zeaxanthin and Visual Function Study (ZVF) FDA IND #78, 973

BACKGROUND

The purpose of this study is to evaluate whether dietary supplementation with the carotenoid zeaxanthin (Zx) raises macula pigment optical density (MPOD) and has unique visual benefits for patients with early atrophic macular degeneration having visual symptoms but lower-risk National Institute of Health/National Eye Institute/Age-Related Eye Disease Study characteristics.

METHODS

This was a 1-year, n = 60 (57 men, 3 women), 4-visit, intention-to-treat, prospective, randomized controlled clinical trial of patients (74.9 years, standard deviation [SD] 10) with mild-to-moderate age-related macular degeneration (AMD) randomly assigned to 1 of 2 dietary supplement carotenoid pigment intervention groups: 8 mg Zx (n = 25) and 8 mg Zx plus 9 mg lutein (L) (n = 25) or 9 mg L ("Faux Placebo," control group, n = 10). Analysis was by Bartlett's test for equal variance, 3-way repeated factors analysis of variance, independent t test (P < 0.05) for variance and between/within group differences, and post-hoc Scheffé's tests. Estimated foveal heterochromic flicker photometry, 1° macular pigment optical density (MPOD QuantifEye(®)), low- and high-contrast visual acuity, foveal shape discrimination (Retina Foundation of the Southwest), 10° yellow kinetic visual fields (KVF), glare recovery, contrast sensitivity function (CSF), and 6° blue cone ChromaTest(®) color thresholds were obtained serially at 4, 8, and 12 months.

RESULTS

Ninety percent of subjects completed ≥ 2 visits with an initial Age-Related Eye Disease Study report #18 retinopathy score of 1.4 (1.0 SD)/4.0 and pill intake compliance of 96% with no adverse effects. There were no intergroup differences in 3 major AMD risk factors: age, smoking, and body mass index as well as disease duration and Visual Function Questionnaire 25 composite score differences. Randomization resulted in equal MPOD variance and MPOD increasing in each of the 3 groups from 0.33 density units (du) (0.17 SD) baseline to 0.51 du (0.18 SD) at 12 m, (P = 0.03), but no between-group differences (Analysis of Variance; P = 0.47). In the Zx group, detailed high-contrast visual acuity improved by 1.5 lines, Retina Foundation of the Southwest shape discrimination sharpened from 0.97 to 0.57 (P = 0.06, 1-tail), and a larger percentage of Zx patients experienced clearing of their KVF central scotomas (P = 0.057). The "Faux Placebo" L group was superior in terms of low-contrast visual acuity, CSF, and glare recovery, whereas Zx showed a trend toward significance.

CONCLUSION

In older male patients with AMD, Zx-induced foveal MPOD elevation mirrored that of L and provided complementary distinct visual benefits by improving foveal cone-based visual parameters, whereas L enhanced those parameters associated with gross detailed rod-based vision, with considerable overlap between the 2 carotenoids. The equally dosed (atypical dietary ratio) Zx plus L group fared worse in terms of raising MPOD, presumably because of duodenal, hepatic-lipoprotein or retinal carotenoid competition. These results make biological sense based on retinal distribution and Zx foveal predominance.

Effect of 1-year lutein supplementation on macular pigment optical density and visual function

BACKGROUND

Although it is known that antioxidants including lutein can affect macular pigment optical density (MPOD) and visual function, we still have much to learn about their effect. Our aim was to assess the 1-year changes in MPOD and visual function in response to supplementation containing lutein.

METHODS

We prospectively measured the MPOD level of those who received a supplement containing 6 mg of lutein daily for 1 year. MPOD level was measured every 3 months by using autofluorescence spectrometry with the two-wavelength method. Other examinations, including contrast sensitivity and retinal sensitivity were also measured every 3 or 6 months. Stepwise regression analysis was performed to determine the factors that correlated with the changes observed in those examinations.

RESULTS

Forty-three eyes of 43 Japanese subjects, including five normal eyes, five fellow eyes with central serous chorioretinopathy (CSC), and 33 fellow eyes with age-related macular degeneration (AMD) were enrolled. The higher baseline MPOD level was correlated with the eye with a clear intraocular lens (IOL). Although no time-dependent changes in the MPOD level were obtained in any area, subjects without cardiovascular diseases showed higher increase in the MPOD level. We observed significant increases in the contrast sensitivity at 1 year (p = 0.0124) and in the retinal sensitivity at 6 months (p < 0.0001) and 1 year (p < 0.0001). Stepwise regression analysis showed that nonsmokers had increased contrast sensitivity (p = 0.0173), and the fellow eye of those with CSC had less of an increase in retinal sensitivity (p = 0.0491).

CONCLUSIONS

Daily supplementation with 6 mg of lutein did not affect the MPOD level for 1 year, suggesting that 6 mg of lutein may be insufficient to increase the MPOD level. However, supplementation seems to improve visual functions such as contrast sensitivity and retinal sensitivity.