Dietary habits are major determinants of the plasma antioxidant status in healthy elderly subjects

Previous studies indicate that regular consumption of a diet rich in fruits and vegetables is associated with a lower risk for age-related diseases. The aim of the present study was to evaluate whether the often-reported age-related decrease of plasma antioxidants in man depends on differences in dietary intake or on other age- and gender-related factors. In this observational case-control study, thirty-nine community-dwelling healthy subjects aged 65 years and older consuming high intakes of fruits and vegetables daily (HI) and forty-eight healthy subjects aged 65 and older consuming low intakes of fruit and vegetables daily (LI) were enrolled. Plasma levels of retinol, tocopherols, carotenoids and malondialdehyde (MDA) as well as content of protein carbonyls in Ig G were measured. Plasma levels of retinol, tocopherols and carotenoids were significantly higher in group HI than in group LI subjects independent of age and gender. MDA levels were inversely correlated with vitamin A and α-carotene. Protein carbonyls were inversely correlated with γ-tocopherol. In the elderly, a higher daily intake of fruits and vegetables is associated with an improved antioxidant status in comparison to subjects consuming diets poor in fruits and vegetables. Modification of nutritional habits among other lifestyle changes should be encouraged to lower prevalence of disease risk factors in later life. © The Authors 2005.

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.

The effect of ageing on macrophage Toll-like receptor-mediated responses in the fight against pathogens

The cellular changes during ageing are incompletely understood yet immune system dysfunction is implicated in the age-related decline in health. The acquired immune system shows a functional decline in ability to respond to new pathogens whereas serum levels of cytokines are elevated with age. Despite these age-associated increases in circulating cytokines, the function of aged macrophages is decreased. Pathogen-associated molecular pattern receptors such as Toll-like receptors (TLRs) are vital in the response of macrophages to pathological stimuli. Here we review the evidence for defective TLR signalling in normal ageing. Gene transcription, protein expression and cell surface expression of members of the TLR family of receptors and co-effector molecules do not show a consistent age-dependent change across model systems. However, there is evidence for impaired downstream signalling events, including inhibition of positive and activation of negative modulators of TLR induced signalling events. In this paper we hypothesize that despite a poor inflammatory response via TLR activation, the ineffective clearance of pathogens by macrophages increases the duration of their activation and contributes to perpetuation of inflammatory responses and ageing.

Overlap between neurodegenerative disorders

Neurodegenerative disorders are characterized by the formation of distinct pathological changes in the brain, including extracellular protein deposits, cellular inclusions, and changes in cell morphology. Since the earliest published descriptions of these disorders, diagnosis has been based on clinicopathological features, namely, the coexistence of a specific clinical profile together with the presence or absence of particular types of lesion. In addition, the molecular profile of lesions has become an increasingly important feature both in the diagnosis of existing disorders and in the description of new disease entities. Recent studies, however, have reported considerable overlap between the clinicopathological features of many disorders leading to difficulties in the diagnosis of individual cases and to calls for a new classification of neurodegenerative disease. This article discusses: (i) the nature and degree of the overlap between different neurodegenerative disorders and includes a discussion of Alzheimer's disease, dementia with Lewy bodies, the fronto-temporal dementias, and prion disease; (ii) the factors that contribute to disease overlap, including historical factors, the presence of disease heterogeneity, age-related changes, the problem of apolipoprotein genotype, and the co-occurrence of common diseases; and (iii) whether the current nosological status of disorders should be reconsidered.

Carotenoids and ocular disease: a review

Background: Carotenoids are not considered to be essential nutrients, but their antioxidant and photoprotective properties have prompted interest in their potential role in disease prevention. Our aim is to review the evidence In relation to ocular disease. Method: Web of Science and Medline via PubMed database search. Results Lutein and zeaxanthin intake has been associated with a 22% reduced risk of cataract extraction in women (RR 0.78, p = 0.04), and a 19% lower risk of cataract in men (RR 0.8, p = 0, 03). A randomised controlled trial (RCT) found a significant improvement in visual acuity in cataract patients supplemented with lutein. Two RCTs investigating the effect of P-carotene, in combination with other nutrients, on cataract report conflicting results. Several studies show no inverse association between cataract and P-carotene. Lutein and zeaxanthin are the only carotenoids found in the human macula. RCTs have found beneficial effects of both lutein and beta-carotene supplementation, in combination with other antioxidants, on visual function age-related macular disease affected subjects. Evidence for a role of lutein in preventing deterioration of visual function in retinitis pigmentosa patients is conflicting. CONCLUSIONS: Further research into the role of lutein and zeaxanthin in prevention of onset and progression of ocular disease is warranted.

A review of the surgical options for the correction of presbyopia

Presbyopia is an age-related eye condition where one of the signs is the reduction in the amplitude of accommodation, resulting in the loss of ability to change the eye's focus from far to near. It is the most common age-related ailments affecting everyone around their mid-40s. Methods for the correction of presbyopia include contact lens and spectacle options but the surgical correction of presbyopia still remains a significant challenge for refractive surgeons. Surgical strategies for dealing with presbyopia may be extraocular (corneal or scleral) or intraocular (removal and replacement of the crystalline lens or some type of treatment on the crystalline lens itself). There are however a number of limitations and considerations that have limited the widespread acceptance of surgical correction of presbyopia. Each surgical strategy presents its own unique set of advantages and disadvantages. For example, lens removal and replacement with an intraocular lens may not be preferable in a young patient with presbyopia without a refractive error. Similarly treatment on the crystalline lens may not be a suitable choice for a patient with early signs of cataract. This article is a review of the options available and those that are in development stages and are likely to be available in the near future for the surgical correction of presbyopia.

Ocular blood flow measurements in healthy human myopic eyes

Background. To evaluate the haemodynamic features of young healthy myopes and emmetropes, in order to ascertain the perfusion profile of human myopia and its relationship with axial length prior to reaching a degenerative state. Methods The retrobulbar, microretinal and pulsatile ocular blood flow (POBF) of one eye of each of twenty-two high myopes (N=22, mean spherical equivalent (MSE) =-5.00D), low myopes (N=22, MSE-1.00 to-4.50D) and emmetropes (N=22, MSE±0.50D) was analyzed using color Doppler Imaging, Heidelberg retinal flowmetry and ocular blood flow analyser (OBF) respectively. Intraocular pressure, axial length (AL), systemic blood pressure, and body mass index were measured. Results. When compared to the emmetropes and low myopes, the AL was greater in high myopia (p<0.0001). High myopes showed higher central retinal artery resistance index (CRA RI) (p=0.004), higher peak systolic to end diastolic velocities ratio (CRA ratio) and lower end diastolic velocity (CRA EDv) compared to low myopes (p=0.014, p=0.037). Compared to emmetropes, high myopes showed lower OBFamplitude (OBFa) (p=0.016). The POBF correlated significantly with the systolic and diastolic blood velocities of the CRA (p=0.016, p=0.036). MSE and AL correlated negatively with OBFa (p=0.03, p=0.003), OBF volume (p=0.02, p<0.001), POBF (p=0.01, p<0.001) and positively with CRA RI (p=0.007, p=0.05). Conclusion. High myopes exhibited significantly reduced pulse amplitude and CRA blood velocity, the first of which may be due to an OBF measurement artefact or real decreased ocular blood flow pulsatility. Axial length and refractive error correlated moderately with the ocular pulse and with the resistance index of the CRA, which in turn correlated amongst themselves. It is hypothesized that the compromised pulsatile and CRA haemodynamics observed in young healthy myopes is an early feature of the decrease in ocular blood flow reported in pathological myopia. Such vascular features would increase the susceptibility for vascular and age-related eye diseases.

Ocular and systemic vascular function in human ageing

The importance of vascular risk factors in various age-related pathologies has been extensively researched. Nevertheless, the haemodynamic disturbance occurring in various ocular and systemic vascular beds to impact upon ocular function remained largely unknown. The purpose of the following studies was to explore the presence and impact of both ocular and systemic vascular dysregulation as well as biochemical vascular risk factors in healthy elderly individuals and patients with age-related macular degeneration. Furthermore, the possible role was played by circulatory oxidative stress and its relationship with endothelial dysfunction at both ocular and systemic levels has also been investigated. There were four principal sections to the present work: 1. To assess the relationship between ocular and systemic anti-oxidative defence in healthy individuals The principal findings of this work were: -It has been shown that MPOD significantly and positively related with circulatory GSH levels. 2. To investigate macro- and microcirculation and oxidative stress in early AMD patients without overt systemic disease The principal findings of this work were: -AMD patients exhibit abnormal macrocirculation compared to the controls. -Blood GSSG level was significantly higher in early AMD patients than controls. -AMD patients showed abnormal microcirculation at retinal level compared. -In early AMD patients, retinal venous RT positively correlated with blood GSSG levels. 3. To assess the relationship between ocular vascular function and circulatory markers of endothelial dysfunction and CVD risk The principal findings of this work were: -Age had a positive effect on ET-1, vWF and slope of retinal arterial constriction in otherwise healthy individuals. -Even in otherwise healthy individuals, retinal arterial vascular function showed a significant correlation with circulatory markers of endothelial dysfunction and CVD risk. 4. To assess age-related changes in ANS and vascular function, and their relationship to retinal vascular function parameters The principal findings of this work were: -Elderly individuals demonstrated abnormal circadian changes of PSNS activity compared to middle-aged group. -Elderly groups showed higher ET-1 and vWF level as well as C-IMT and AIx, and also impaired retinal vascular function compared to the middle-aged group. -In the elderly group, impaired retinal vascular function significantly correlated with the dysregulation of PSNS activity.

Nutritional supplementation for type 2 diabetes: a systematic review

The role of nutritional supplementation is of increasing interest with regard to ocular disease. Randomised controlled trials have demonstrated the effectiveness of supplementation for age-related macular degeneration, and formulations are now being developed for use by people with diabetes and diabetic retinopathy. The aim of this review was to synthesise the evidence for use of nutritional supplementation in type 2 diabetes. MEDLINE and EMBASE databases were searched using a systematic approach. Only double-masked randomised controlled trials were selected. A total of 50 trials were identified as suitable for inclusion. The potential role of alpha-lipoic acid, chromium, folic acid, isoflavones, magnesium, Pycnogenol®, selenium, vitamin C, vitamin E, and zinc in the treatment of type 2 diabetes is discussed. The review of trials identifies positive effects of these nutrients on various outcome measures relating to insulin resistance and cardiovascular factors. Chromium was the most studied supplement, accounting for 16 of the 50 trials. A majority of the trials found a positive effect of chromium on fasting plasma glucose. Isoflavones were found to have a positive effect on insulin resistance and cardiovascular outcome measures, but only when combined with soy proteins. Vitamin E is reported to reduce oxidative stress at levels of 200 mg day-1 or more.

Possible contraindications and adverse reactions associated with the use of ocular nutritional supplements

The role of oxidation in the development of age-related eye disease has prompted interest in the use of nutritional supplementation for prevention of onset and progression. Our aim is to highlight possible contraindications and adverse reactions of isolated or high dose ocular nutritional supplements. Web of Science and PubMed database searches were carried out, followed by a manual search of the bibliographies of retrieved articles. Vitamin A should be avoided in women who may become pregnant, in those with liver disease, and in people who drink heavily. Relationships have been found between vitamin A and reduced bone mineral density, and beta-carotene and increased risk of lung cancer in smoking males. Vitamin E and Ginkgo biloba have anticoagulant and anti-platelet effects respectively, and high doses are contraindicated in those being treated for vascular disorders. Those patients with contraindications or who are considered at risk of adverse reactions should be advised to seek specialist dietary advice via their medical practitioner. © 2005 The College of Optometrists.

An ideal ocular nutritional supplement?

The role of nutritional supplementation in prevention of onset or progression of ocular disease is of interest to health care professionals and patients. The aim of this review is to identify those antioxidants most appropriate for inclusion in an ideal ocular nutritional supplement, suitable for those with a family history of glaucoma, cataract, or age-related macular disease, or lifestyle factors predisposing onset of these conditions, such as smoking, poor nutritional status, or high levels of sunlight exposure. It would also be suitable for those with early stages of age-related ocular disease. Literature searches were carried out on Web of Science and PubMed for articles relating to the use of nutrients in ocular disease. Those highlighted for possible inclusion were vitamins A, B, C and E, carotenoids beta-carotene, lutein, and zeaxanthin, minerals selenium and zinc, and the herb, Ginkgo biloba. Conflicting evidence is presented for vitamins A and E in prevention of ocular disease; these vitamins have roles in the production of rhodopsin and prevention of lipid peroxidation respectively. B vitamins have been linked with a reduced risk of cataract and studies have provided evidence supporting a protective role of vitamin C in cataract prevention. Beta-carotene is active in the prevention of free radical formation, but has been linked with an increased risk of lung cancer in smokers. Improvements in visual function in patients with age-related macular disease have been noted with lutein and zeaxanthin supplementation. Selenium has been linked with a reduced risk of cataract and activates the antioxidant enzyme glutathione peroxidase, protecting cell membranes from oxidative damage while zinc, although an essential component of antioxidant enzymes, has been highlighted for risk of adverse effects. As well as reducing platelet aggregation and increasing vasodilation, Gingko biloba has been linked with improvements in pre-existing field damage in some patients with normal tension glaucoma. We advocate that vitamins C and E, and lutein/zeaxanthin should be included in our theoretically ideal ocular nutritional supplement.

Clinical characteristics of unilateral myopic anisometropia in a juvenile optometric practice population

Purpose: A retrospective study of longitudinal case histories, undertaken to establish the clinical and statistical characteristics of unilateral myopic anisometropia (UMA) amongst the juvenile and adolescent population at an optometric practice, is reported. UMA was defined as that specific refractive state where an unequivocally myopic eye is paired with a 'piano' [spherical equivalent refraction, (SER) = ±0.25 Dioptres (D)] companion eye. Methods: The clinical records of all patients aged <19 years on file at an established independent optometric practice were categorised as 'myopic' (SER ≤-0.50 D), 'hypermetropie' (≥+0.75 D) or 'emmetropic' (≥-0.37≤+0.62 D). Subsequently all juvenile patients matching the UMA criterion, together with a case-matched group of bilaterally myopic individuals, were selected as the comparative study populations. Results: A total of 14.4% (n = 21 of 146) of the juvenile myopic case histories were identified as cases of UMA. More than half of these UMA cases emerged between the ages of 11.5 and 13.5 years. There was a marked female gender bias. The linear gradient of the age-related mean refractive trend in the myopic eye of the UMA population was not statistically significantly different (p > 0.1) to that fitted to the ametropic progression recorded in either eye of the case-matched population of young bilateral myopes; uniquely the slope associated with the companion eye of UMA cases was statistically significantly (p < 0.025) less steep. Compared with bilateral myopes fewer cases of UMA required a refractive correction to relieve visual or asthenopic symptoms, and this initial correction was dispensed on average 1 year later (at age 12.7 years) in UMA patients. Conclusions: Individuals identified as demonstrating clinically-defined UMA can be considered as distinct but functionally normal cases on the continuum of human refractive error. However, any unilaterally-acting determining factor(s) underlying the genesis of the condition remain obscure. © 2004 The College of Optometrists.

Asymmetrical switch costs in children

Switching between tasks produces decreases in performance as compared to repeating the same task. Asymmetrical switch costs occur when switching between two tasks of unequal difficulty. This asymmetry occurs because the cost is greater when switching to the less difficult task than when switching to the more difficult task. Various theories about the origins of these asymmetrical switch costs have emerged from numerous and detailed experiments with adults. There is no documented evidence of asymmetrical switch costs in children. We conducted a series of studies that examined age-related changes in asymmetrical switch costs, within the same paradigm. Similarities in the patterns of asymmetrical switch costs between children and adults suggested that theoretical explanations of the cognitive mechanisms driving asymmetrical switch costs in adults could be applied to children. Age-related differences indicate that these theoretical explanations need to incorporate the relative contributions and interactions of developmental processes and task mastery. © 2006 Elsevier Inc. All rights reserved.

The MacDQoL individualized measure of the impact of macular degeneration on quality of life: reliability and responsiveness

PURPOSE: To investigate the MacDQoL test-retest reliability and sensitivity to change in vision over a period of one year in a sample of patients with age-related macular degeneration (AMD). DESIGN: A prospective, observational study. METHOD: Patients with AMD from an ophthalmologist's list (n = 135) completed the MacDQoL questionnaire by telephone interview and underwent a vision assessment on two occasions, one year apart. RESULTS: Among participants whose vision was stable over one year (n = 87), MacDQoL scores at baseline and follow-up were highly correlated (r = 0.95; P < .0001). Twelve of the 22 scale items had intraclass correlations of >.80; only two were correlated <.7. There was no difference between baseline and follow-up scores (P = .85), indicating excellent test-retest reliability. Poorer quality of life (QoL) at follow-up, measured by the MacDQoL present QoL overview item, was associated with deterioration in both the better eye and binocular distance visual acuity [VA] (r = 0.29; P = .001, r = 0.21; P = .016, respectively; n = 135). There was a positive correlation between deterioration in the Mac. DQoL average weighted impact score and deterioration in both binocular near VA and reading speed (r = 0.20; P = .019, r = 0.18; P = .041, respectively; n = 135). CONCLUSION: The MacDQoL has excellent test-retest reliability. Its sensitivity to change in vision status was demonstrated in correlational analyses. The measure indicates that the negative impact of AMD on QoL increases with increasing severity of visual impairment.

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.