Macular Degeneration: Beatty S

Neelam K, Nolan J, Chakravarthy U, Beatty S. · Waterford Institute of Technology, Waterford Regional Hospital, Waterford, Republic of Ireland. · Surv Ophthalmol. · Pubmed #19298899 No free full text.

Abstract: Age-related macular degeneration (AMD), the late stage of age-related maculopathy (ARM), is the leading cause of blind registration in developed countries. The visual loss in AMD occurs due to dysfunction and death of photoreceptors (rods and cones) secondary to an atrophic or a neovascular event. The psychophysical tests of vision, which depend on the functional status of the photoreceptors, may detect subtle alterations in the macula before morphological fundus changes are apparent ophthalmoscopically, and before traditional measures of visual acuity exhibit deterioration, and may be a useful tool for assessing and monitoring patients with ARM. Furthermore, worsening of these visual functions over time may reflect disease progression, and some of these, alone or in combination with other parameters, may act as a prognostic indicator for identifying eyes at risk for developing neovascular AMD. Lastly, psychophysical tests often correlate with subjective and relatively undefined symptoms in patients with early ARM, and may reflect limitation of daily activities for ARM patients. However, clinical studies investigating psychophysical function have largely been cross-sectional in nature, with small sample sizes, and lack consistency in terms of the grading and classification of ARM. This article aims to comprehensively review the literature germane to psychophysical tests in ARM, and to furnish the reader with an insight into this complex area of research.

Neelam K, Hogg RE, Stevenson MR, Johnston E, Anderson R, Beatty S, Chakravarthy U. · Waterford Institute of Technology, Waterford, Republic of Ireland. · Ophthalmic Epidemiol. · Pubmed #19065432 No free full text.

Abstract: Age-related macular degeneration (AMD), is the leading cause of blind registration in the Western World among individuals 65 years or older. Early AMD, a clinical state without overt functional loss, is said to be present clinically when yellowish deposits known as drusen and/or alterations of fundus pigmentation are seen in the macular retina. Although the etiopathogenesis of AMD remains uncertain, there is a growing body of evidence in support of the view that cumulative oxidative damage plays a causal role. Appropriate dietary antioxidant supplementation is likely to be beneficial in maintaining visual function in patients with AMD, and preventing or delaying the progression of early AMD to late AMD. The Carotenoids in Age-Related Maculopathy (CARMA) Study is a randomized and double-masked clinical trial of antioxidant supplementation versus placebo in 433 participants with either early AMD features of sufficient severity in at least one eye or any level of AMD in one eye with late AMD (neovascular AMD or central geographic atrophy) in the fellow eye. The aim of the CARMA Study is to investigate whether lutein and zeaxanthin, in combination with co-antioxidants (vitamin C, E, and zinc), has a beneficial effect on visual function and/or prevention of progression from early to late stages of disease. The primary outcome is improved or preserved distance visual acuity at 12 months. Secondary outcomes include improved or preserved interferometric acuity, contrast sensitivity, shape discrimination ability, and change in AMD severity as monitored by fundus photography. This article outlines the CARMA Study design and methodology, including its rationale.

Loane E, Kelliher C, Beatty S, Nolan JM. · Macular Pigment Research Group, Waterford Institute of Technology, Cork Road, Waterford, Ireland. · Br J Ophthalmol. · Pubmed #18669545 No free full text.

Abstract: Age-related maculopathy (ARM) remains the most common cause of blind registration in people aged 50 years or over in the developed world, and its prevalence continues to rise. Although effective new treatments have become available in the recent past, these are expensive and cumbersome to the healthcare provider and to the patient, and many cases remain resistant to such therapy. There is a biologically plausible rationale whereby macular pigment, which is entirely of dietary origin, may prevent or delay the onset, or ameliorate the clinical course, of ARM. In this article, we review this rationale, and critically appraise the current evidence base germane to the use of supplements containing the macular carotenoids in patients with, or at risk of developing, ARM.

Beatty S, van Kuijk FJ, Chakravarthy U. · Macular Pigment Research Group, Waterford Institute of Technology, Waterford, Ireland. · Invest Ophthalmol Vis Sci. · Pubmed #18326700 links to  free full text

This publication has no abstract.

Loane E, Nolan JM, O'Donovan O, Bhosale P, Bernstein PS, Beatty S. · Macular Pigment Research Group, Waterford Institute of Technology, Waterford, Ireland. · Surv Ophthalmol. · Pubmed #18191658 No free full text.

Abstract: Age-related macular degeneration (AMD) is the most common cause of irreversible blindness in the elderly population in the western world. The etiology and pathogenesis of this disease remain unclear. However, there is an increasing body of evidence supporting the hypothesis that the macular pigment carotenoids, lutein and zeaxanthin, play an important role in protection against AMD, by filtering out blue light at a pre-receptoral level, or by quenching free radicals. Lutein and zeaxanthin are dietary xanthophyll carotenoids, which are delivered to the retina via plasma lipoproteins. The biological mechanisms governing retinal capture and accumulation of lutein and zeaxanthin, to the exclusion of other carotenoids, are still poorly understood. Although these mechanisms remain unclear, it is possible that selective capture of these carotenoids is related to lipoprotein, or apolipoprotein, function and profile. Xanthophyll-binding proteins appear to play an important role in the retinal capture of the xanthophyll carotenoids. The Pi isoform of GSTP1 has been isolated as a specific binding protein for zeaxanthin. The binding protein responsible for retinal uptake of lutein remains elusive. This article reviews the literature germane to the mechanisms involved in the capture, accumulation and stabilization of lutein and zeaxanthin by the retina, and the processes involved in their transport in serum.

O'Connell E, Neelam K, Nolan J, Au Eong KG, Beatty S. · Department of Ophthalmology, Waterford Regional Hospital, Waterford, Republic of Ireland. · Ann Acad Med Singapore. · Pubmed #17160199 links to  free full text

Abstract: Lutein (L) and zeaxanthin (Z) are concentrated at the macula, where they are collectively known as macular pigment (MP), and where they are believed to play a major role in protecting retinal tissues against oxidative stress. Whilst the exact pathogenesis of age-related maculopathy (ARM) remains unknown, the disruption of cellular processes by oxidative stress may play an important role. Manipulation of dietary intake of L and Z has been shown to augment MP, thereby raising hopes that dietary supplementation with these carotenoids might prevent, delay, or modify the course of ARM. This article discusses the scientific rationale supporting the hypothesis that L and Z are protective against ARM, and presents the recent evidence germane to this theory.

Nolan JM, Stack J, O' Donovan O, Loane E, Beatty S. · Macular Pigment Research Group, Department of Chemical and Life Sciences, Waterford Institute of Technology, Cork Road, Waterford, Ireland. · Exp Eye Res. · Pubmed #17083932 No free full text.

Abstract: Macular pigment (MP) is composed of the two dietary carotenoids lutein (L) and zeaxanthin (Z), and is believed to protect against age-related maculopathy (ARM). This study was undertaken to investigate MP optical density with respect to risk factors for ARM, in 828 healthy subjects from an Irish population. MP optical density was measured psychophysically using heterochromatic flicker photometry, serum L and Z were quantified by HPLC, and dietary intake of L and Z was assessed using a validated food-frequency questionnaire. Clinical and personal details were also recorded, with particular attention directed towards risk factors for ARM. We report a statistically significant age-related decline in MP optical density (r2=0.082, p<0.01). Current and past smokers had lower average MP optical density than never smokers and this difference was statistically significant (p<0.01). Subjects with a confirmed family history of ARM had significantly lower levels of MP optical density than subjects with no known family history of disease (p<0.01). For each of these established risk factors, their statistically significant negative association with MP persisted after controlling for the other two, and also after controlling for other potentially confounding variables such as sex, cholesterol, dietary and serum L (p<0.01). In the absence of retinal pathology, and in advance of disease onset, the relative lack of MP seen in association with increasing age, tobacco use and family history of ARM supports the hypothesis that the enhanced risk that these variables represent for ARM may be attributable, at least in part, to a parallel deficiency of macular carotenoids.

Byrne S, Beatty S. · Department of Ophthalmology, Royal Victoria Infirmary, Newcastle-upon-Tyne, UK. · Ir J Med Sci. · Pubmed #15029987 No free full text.

Abstract: BACKGROUND: Age-related macular degeneration (AMD) is the leading cause of visual impairment and blindness in the Western World in those aged 65 and older. At present, several treatment modalities are utilised and several more are undergoing investigation in an attempt to retard the occurrence and progression of this devastating condition. AIMS: To provide the non-ophthalmologist with an understanding of the current treatment options available to patients suffering from all variants of AMD. METHODS: Medline and Embase search. RESULTS: Several treatment modalities have been investigated and utilised in the treatment of all variants of this condition. While promising results have been reported, no treatment is ideal. CONCLUSION: While no curative treatment for this condition currently exists, early recognition and treatment, if indicated, have been shown to reduce the risk of severe vision loss in patients with this condition.

Beatty S, Koh H, Phil M, Henson D, Boulton M. · Academic Department of Ophthalmology, Manchester Royal Eye Hospital, Manchester, United Kingdom. · Surv Ophthalmol. · Pubmed #11033038 No free full text.

Abstract: Age-related macular degeneration (AMD) is the leading cause of blind registration in the developed world, and yet its pathogenesis remains poorly understood. Oxidative stress, which refers to cellular damage caused by reactive oxygen intermediates (ROI), has been implicated in many disease processes, especially age-related disorders. ROIs include free radicals, hydrogen peroxide, and singlet oxygen, and they are often the byproducts of oxygen metabolism. The retina is particularly susceptible to oxidative stress because of its high consumption of oxygen, its high proportion of polyunsaturated fatty acids, and its exposure to visible light. In vitro studies have consistently shown that photochemical retinal injury is attributable to oxidative stress and that the antioxidant vitamins A, C, and E protect against this type of injury. Furthermore, there is strong evidence suggesting that lipofuscin is derived, at least in part, from oxidatively damaged photoreceptor outer segments and that it is itself a photoreactive substance. However, the relationships between dietary and serum levels of the antioxidant vitamins and age-related macular disease are less clear, although a protective effect of high plasma concentrations of alpha-tocopherol has been convincingly demonstrated. Macular pigment is also believed to limit retinal oxidative damage by absorbing incoming blue light and/or quenching ROIs. Many putative risk-factors for AMD have been linked to a lack of macular pigment, including female gender, lens density, tobacco use, light iris color, and reduced visual sensitivity. Moreover, the Eye Disease Case-Control Study found that high plasma levels of lutein and zeaxanthin were associated with reduced risk of neovascular AMD. The concept that AMD can be attributed to cumulative oxidative stress is enticing, but remains unproven. With a view to reducing oxidative damage, the effect of nutritional antioxidant supplements on the onset and natural course of age-related macular disease is currently being evaluated.

Beatty S, Boulton M, Henson D, Koh HH, Murray IJ. · University Department of Ophthalmology, Manchester Royal Eye Hospital. · Br J Ophthalmol. · Pubmed #10381676 links to  free full text

This publication has no abstract.

Neelam K, Muldrew A, Hogg R, Stack J, Chakravarthy U, Beatty S. · Department of Chemical and Life Sciences, Waterford Institute of Technology, Republic of Ireland. · Retina. · Pubmed #18997640 No free full text.

Abstract: PURPOSE: To compare clinical age-related maculopathy (ARM) grading using slit-lamp biomicroscopy (SLB) versus photographic grading of stereoscopically captured fundus photographs (FP) using a high-resolution fundus camera. METHODS: A subset (129) of participants in the Carotenoids in ARM study were clinically graded for ARM signs and the corresponding FPs were graded in an accredited reading center. RESULTS: Drusen were said to be present in 192 (94.5%) eyes graded by FP, and in 165 (82.5%) eyes examined by SLB (agreement = 84%, k = 0.23). A good and modest degree of agreement was observed between SLB and FP for quantification of total drusen number (agreement = 81%, k = 0.33) and for classification of drusen subtypes (agreement = 60%, k = 0.33), respectively. Localization of drusen to either the inner zone or the outer zone was comparable for both techniques of ARM grading (inner zone: agreement = 89%; outer zone: agreement = 88%, k = 0.39). Agreement between SLB and FP was 76% (k = 0.46) for identification of any pigment abnormality; however, agreement was less for hypo-pigmentation abnormalities (agreement = 64%, k = 0.21). CONCLUSIONS: From the statistical perspective, SLB grading of ARM is generally comparable with findings from standardized grading of FP. However, the lower levels of agreement for classification of drusen subtypes and detection of hypo-pigmentation suggest these features may go unrecorded in a study which relies on SLB for grading ARM.

O'Connell ED, Nolan JM, Stack J, Greenberg D, Kyle J, Maddock L, Beatty S. · Macular Pigment Research Group, Department of Chemical and Life Sciences, Waterford Institute of Technology, Waterford, Ireland. · Am J Clin Nutr. · Pubmed #18326611 links to  free full text

Abstract: BACKGROUND: Evidence continues to accumulate that oxidative stress is etiologically important in the pathogenesis of age-related maculopathy (ARM) and that appropriate antioxidants of dietary origin may protect against this condition. OBJECTIVE: Risk factors for ARM may be classed as established or putative. We report a study designed to investigate whether such risk factors are associated with a dietary lack of antioxidants relevant to retinal health. DESIGN: Dietary, anthropometric, and sociodemographic details relating to 828 healthy Irish subjects aged 20-60 y were recorded in a cross-sectional fashion and analyzed for associations between risk factors for ARM and dietary intake of relevant nutrients. RESULTS: Of the established risk factors for ARM, increasing age was associated with a relative lack of dietary zeaxanthin (P < 0.05) and tobacco use with a relative lack of dietary vitamin C (P < 0.05). Of the putative risk factors for ARM, alcohol consumption was associated with a relative lack of dietary alpha-linoleic acid (P < 0.05), and female sex was associated with a relative lack of dietary zinc (P < 0.05). CONCLUSIONS: We showed that several variables related to risk for ARM are associated with a relative dietary lack of key nutrients. Our finding that age, the most important and universal risk factor for ARM, is associated with a relative lack of dietary zeaxanthin, is an important finding that warrants further investigation.

Loane E, Stack J, Beatty S, Nolan JM. · Macular Pigment Research Group, Department of Chemical & Life Sciences, Waterford Institute of Technology, Waterford, Ireland. · Curr Eye Res. · Pubmed #17612971 No free full text.

Abstract: PURPOSE: To compare macular pigment optical density using two different heterochromatic flicker photometers. METHODS: We measured macular pigment optical density in 121 healthy subjects using heterochromatic flicker photometry. RESULTS: The mean (+/-SD) macular pigment optical density measured using the Maculometer was 0.394 (+/-0.170), and that using the Densitometer was 0.395 (+/-0.189). The difference in measurements on each instrument was influenced by age and macular pigment levels. CONCLUSIONS: On average, there is no difference in measurements provided by these two instruments. The Maculometer tends to underestimate macular pigment in older subjects and/or those with higher macular pigment compared with the Densitometer.

Trieschmann M, Beatty S, Nolan JM, Hense HW, Heimes B, Austermann U, Fobker M, Pauleikhoff D. · Institute of Ophthalmology, St. Franziskus Hospital, and Institute of Epidemiology, University of Münster, Germany. · Exp Eye Res. · Pubmed #17306793 No free full text.

Abstract: Macular pigment (MP), consisting of lutein (L) and zeaxanthin (Z), is believed to protect the retina from photo-oxidative damage. The current study investigates, in terms of MP optical density (MPOD) and serum concentrations of its constituent carotenoids, response to supplemental L and Z, and co-antioxidants. An intervention (I) group, consisting of 108 subjects (mean [+/-SD] age: 71.5 [+/-7.1] years), of which 92.6% exhibited features of age-related macular degeneration (AMD), received a daily supplement consisting of 12 mg L and 1 mg Z, both provided as ester 120 mg vitamin C, 17.6 mg vitamin E, 10 mg zinc, 40 microg selenium (Ocuvite Luteintrade mark) for a period of 6 months. MPOD was measured, by 2-wavelength autofluorescence (AF), on five occasions during the period of supplementation, and once again 3 months following discontinuation of the supplement. A control (C) group of 28 subjects (mean [+/-SD] age: 71.0 [+/-8.1] years), who received no dietary supplementation or modification, was examined at baseline and once again after a mean of 29.4 (+/-9.3) weeks. At baseline, mean (+/-SD) MPOD (at 0.5 degrees) was 0.504 (+/-0.197) and 0.525 (+/-0.189) in the I and C groups, respectively. There was a statistically significant increase in MPOD (at 0.5 degrees) for the I group (0.1 [+/-0.009]; p<0.0008), whereas no significant increase was seen in the C group (0.03 [+/-0.02]; p>0.05), over the period of supplementation. In order to classify supplemented subjects into quartiles, in terms of MPOD response, we calculated the difference between MPOD (at 0.5 degrees) at visit 6 and at baseline (visit 1). Quartile 1 (the "non-responder" quartile) displayed no increase in MPOD (at 0.5 degrees), in spite of rises seen in serum concentrations of L and Z. The three "responder" quartiles reached similar final plateaus of MPOD (at 0.5 degrees), reflected in final mean (+/-SEM) values of 0.59 (+/-0.04) optical density unit (ODU), 0.64 (+/-0.03) ODU and 0.64 (+/-0.03) ODU for quartiles 2, 3 and 4, respectively. Subjects with low baseline MPOD were more likely to exhibit a dramatic rise in MPOD, or to exhibit no rise in MPOD, in response to supplements than subjects with medium to high baseline MPOD values. Supplementation with 12 mg L and 1 mg Z, combined with co-antioxidants, resulted in an increase of MPOD at 0.5 degrees eccentricity in a majority of subjects, including those afflicted with AMD. However, there remains a substantial proportion of subjects for whom, in spite of rises in serum concentrations of L and Z in these subjects, MPOD augmentation in response to supplemental L, Z and co-antioxidants could not be detected over the study period, thus indicating that intestinal malabsorption of these carotenoids is not responsible for the lack of a macular response to such supplements. Further, our results suggest that saturable mechanisms play a role in the retinal capture and/or stabilisation of the macular carotenoids.

Nolan JM, Stack J, O'connell E, Beatty S. · Macular Pigment Research Group, Department of Chemical and Life Sciences, Waterford Institute of Technology, Cork Road, Waterford, Ireland. · Invest Ophthalmol Vis Sci. · Pubmed #17251452 links to  free full text

Abstract: PURPOSE: Lutein (L) and zeaxanthin (Z) are two dietary carotenoids that accumulate at the macula, where they are collectively known as macular pigment (MP). There is a biologically plausible rationale, with some supporting evidence, that MP may protect against age-related maculopathy (ARM). This study was undertaken to investigate the relationship between dietary intake of L and Z, serum concentrations of these carotenoids, and MP optical density in 828 healthy Irish subjects. METHODS: Dietary intake of L and Z was assessed with a validated food-frequency questionnaire, and serum concentrations of these carotenoids were quantified by high-performance liquid chromatography. MP optical density was measured psychophysically, using heterochromatic flicker photometry. Demographic data, lifestyle data, and general health status, were also recorded by questionnaire, with particular attention directed toward risk-factors (established and putative) for ARM. RESULTS: The relationships between MP optical density, serum concentrations of L (and Z), and dietary intake of L (and Z) were positive and statistically significant when analyzed for the entire study group (r = 0.136-0.303; P < 0.01 for all). Subjects with a clinically confirmed family history of ARM, current heavy cigarette smokers, subjects aged more than 53 years, and subjects with a body mass index (BMI) >27, did not demonstrate a positive and significant relationship between MP optical density and serum concentrations of Z (r = 0.041, r = 0.001, r = 0.074 and r = 0.082, respectively; P > 0.05 for all). However, there was a positive and significant relationship between MP optical density and serum concentrations of L in the presence of all these risk factors (r = 0.165 to 0.257), except for current heavy smokers (r = 0.042; P > 0.05). CONCLUSIONS: For subjects at increased risk of ARM (e.g., subjects with a clinically confirmed family history of ARM, current heavy cigarette smokers, subjects aged > 53 years and subjects with a BMI > 27) retinal capture and/or retinal stabilization of Z appears to be compromised, whereas retinal uptake and/or stabilization of L appears to be compromised in current heavy smokers only. Given the lack of MP in association with risk for ARM, the findings indicate that a retina predisposed to this condition may have an impaired ability to accumulate circulating Z.

Liew SH, Gilbert CE, Spector TD, Mellerio J, Van Kuijk FJ, Beatty S, Fitzke F, Marshall J, Hammond CJ. · Twin Research and Genetic Epidemiology Unit, St Thomas' Hospital, London, UK. · Exp Eye Res. · Pubmed #16380117 No free full text.

Abstract: Macular pigment (MP) has been suggested to have a protective role in age-related macular degeneration by reducing the amount of oxidative stress on the retina. MP levels peak at the foveal center, where it is found predominantly in the receptor axon and inner plexiform layers of the retina. The purpose of this study was to investigate the relationship between central retinal thickness and macular pigment optical density in a group of healthy subjects. We report that macular pigment optical density (MPOD) has a significant and positive relationship with central retinal thickness as measured by optical coherence tomography. The strength of the observed relationship (r approximately 0.30) was independent of the technique used to measure MPOD, whether heterochromatic flicker photometry (HFP) or 2-wavelength autofluorescence (AF). Of note, there was no statistically demonstrable relationship between MPOD at an eccentricity of 1- or 2-degrees and central retinal thickness. This finding has important implications for future studies investigating MPOD, and its response to dietary modification/supplementation.

Liew SH, Gilbert CE, Spector TD, Mellerio J, Marshall J, van Kuijk FJ, Beatty S, Fitzke F, Hammond CJ. · Twin Research and Genetic Epidemiology Unit, The Rayne Institute, St. Thomas' Hospital, London, United Kingdom. · Invest Ophthalmol Vis Sci. · Pubmed #16303930 links to  free full text

Abstract: PURPOSE: Several studies have reported higher levels of macular pigment (MP) in association with reduced risk for age-related macular degeneration (ARMD), a disease to which there is a genetic predisposition. A classic twin study was performed to determine the heritability of MP in the healthy eye. METHODS: One hundred fifty twin pairs (76 monozygotic [MZ] and 74 dizygotic [DZ]), aged 18 to 50 years, participated. MP optical density was measured psychophysically with heterochromatic flicker photometry (HFP) and also with an imaging method involving fundus autofluorescence (AF). The covariance of MP within MZ and DZ twin pairs was compared, and genetic modeling techniques were used to determine the relative contributions of genes and environment to the variation in MP. RESULTS: The mean MP optical density, measured using HFP, was 0.43 +/- 0.21. Using AF, the mean MP optical density, measured at 1 degrees eccentricity, was 0.28 +/- 0.11. MP optical densities correlated more highly in MZ twins than in DZ twins, according to both HFP (MZ: 0.65; DZ: 0.24) and AF (MZ: 0.83; DZ: 0.50). A model combining additive genetic and unique environmental effects provided the best fit and resulted in MP heritability estimates of 0.67 (95% CI, 0.52-0.77) and 0.85 (95% CI, 0.78-0.90) for HFP and AF readings, respectively. CONCLUSIONS: This classic twin study demonstrates that genetic background is an important determinant of MP optical density, reflected in heritability estimates of 0.67 and 0.85 for HFP and AF measures, respectively.

Koh HH, Murray IJ, Nolan D, Carden D, Feather J, Beatty S. · Optometry Section, School of Chemical and Life Sciences, Singapore Polytechnic, Singapore. · Exp Eye Res. · Pubmed #15183097 No free full text.

Abstract: There is a growing body of evidence which suggests that macular pigment (MP), which is entirely of dietary origin, protects against age-related maculopathy. We evaluated the effect of a daily 20 mg lutein ester (equivalent of 10 mg/day free lutein) supplement in patients with early age-related maculopathy (ARM), in terms of macular pigment optical density (MPOD) and plasma concentrations of lutein. MPOD was measured using a flicker photometric technique in seven ARM sufferers and six age-matched controls over a period of supplementation which lasted 18-20 weeks. Plasma lutein increased from a mean (SD) baseline concentration of 182 (127)ng ml(-1) to a peak of 1077 (165)ng ml(-1) in ARM patients, and from 152 (57) to 1110 (605)ng ml(-1) in control subjects. Mean MPOD had increased significantly from baseline of 0.24 to a peak of 0.31 in ARM sufferers. This mean increment of 0.07 was the same for the age-matched controls (baseline: 0.20; peak: 0.27). The augmentation of MP, and plasma concentrations of lutein, following supplementation in subjects with ARM provides the first evidence the disease is not associated with intestinal malabsorption of the relevant macular carotenoids, and that a diseased macula can accumulate and stabilise lutein and/or zeaxanthin. Furthermore, these results suggest that the beneficial effects of lutein supplementation, if any, may be extended to subjects with established ARM.

Beatty S, Murray IJ, Henson DB, Carden D, Koh H, Boulton ME. · University Department of Ophthalmology, Manchester Royal Eye Hospital, Manchester, UK. · Invest Ophthalmol Vis Sci. · Pubmed #11157880 links to  free full text

Abstract: PURPOSE: Age and advanced disease in the fellow eye are the two most important risk factors for age-related macular degeneration (AMD). In this study, the authors investigated the relationship between these variables and the optical density of macular pigment (MP) in a group of subjects from a northern European population. METHODS: The optical density of MP was measured psychophysically in 46 subjects ranging in age from 21 to 81 years with healthy maculae and in 9 healthy eyes known to be at high-risk of AMD because of advanced disease in the fellow eye. Each eye in the latter group was matched with a control eye on the basis of variables believed to be associated with the optical density of MP (iris color, gender, smoking habits, age, and lens density). RESULTS: There was an age-related decline in the optical density of macular pigment among volunteers with no ocular disease (right eye: r(2) = 0.29, P = 0.0006; left eye: r(2) = 0.29, P < 0.0001). Healthy eyes predisposed to AMD had significantly less MP than healthy eyes at no such risk (Wilcoxon's signed rank test: P = 0.015). CONCLUSIONS: The two most important risk factors for AMD are associated with a relative absence of MP. These findings are consistent with the hypothesis that supplemental lutein and zeaxanthin may delay, avert, or modify the course of this disease.

Beatty S, Au Eong KG, McLeod D, Bishop PN. · Academic Department of Ophthalmology, Manchester Royal Eye Hospital, Manchester. · Br J Ophthalmol. · Pubmed #10502566 links to  free full text

This publication has no abstract.

Sangtam T, Tan CS, Au Eong KG, Beatty S, Kwok AK. · No affiliation provided · Am J Ophthalmol. · Pubmed #16876540 No free full text.

This publication has no abstract.