Age and the transmittance of the human crystalline lens.

Weale, R. A.

doi:10.1113/jphysiol.1988.sp016935

Cited by 269 publications

(191 citation statements)

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“…The decline in macular pigment levels with age correlates well with some, 19,33 but not all, 18,22 recent psychophysical reports of macular pigment levels in normal populations. Some of this drop of Raman signal with age may be the result of increasing yellowing of the lens as subjects age, [34][35][36] but this effect could account for only half of the more than 75% drop in average Raman signal seen between ages 20 and 60 years (see Ref. 27 for a detailed discussion of this issue).…”

Section: Discussionmentioning

confidence: 99%

Resonance Raman measurement of macular carotenoids in normal subjects and in age-related macular degeneration patients

et al. 2002

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Purpose-Dietary carotenoids lutein and zeaxanthin may play a protective role against visual loss from age-related macular degeneration (AMD) through antioxidant and light screening mechanisms. We used a novel noninvasive objective method to quantify lutein and zeaxanthin in the human macula using resonance Raman spectroscopy and compared macular pigment levels in AMD and normal subjects. Design-Observational study of an ophthalmology clinic-based population.Participants and Controls-Ninety-three AMD eyes from 63 patients and 220 normal eyes from 138 subjects.Methods-Macular carotenoid levels were quantified by illuminating the macula with a lowpower argon laser spot and measuring Raman backscattered light using a spectrograph. This technique is sensitive, specific, and repeatable even in subjects with significant macular pathologic features.Main Outcome Measure-Raman signal intensity at 1525 cm −1 generated by the carboncarbon double-bond vibrations of lutein and zeaxanthin.Results-Carotenoid Raman signal intensity declined with age in normal eyes (P < 0.001). Average levels of lutein and zeaxanthin were 32% lower in AMD eyes versus normal elderly control eyes as long as the subjects were not consuming high-dose lutein supplements (P = 0.001). Patients who had begun to consume supplements containing high doses of lutein (≥4 mg/day) regularly after their initial diagnosis of AMD had average macular pigment levels that were in the normal range (P = 0.829) and that were significantly higher than in AMD patients not consuming these supplements (P = 0.038).Conclusions-These findings are consistent with the hypothesis that low levels of lutein and zeaxanthin in the human macula may represent a pathogenic risk factor for the development of Correspondence and reprint requests to Paul S. Bernstein, MD, PhD, Moran Eye Center, University of Utah School of Medicine, 50 North Medical Drive, Salt Lake City, UT 84132. paul.bernstein@hsc.utah.edu. Three authors (PSB, RWM, and WG) and the University of Utah hold patent rights to the ocular Raman technology described in this article, and these authors and the university own significant equity interests in Spectrotek, LC, a company that has licensed the technology.Presented in part as a poster at the annual meeting of the American Academy of Ophthalmology, New Orleans, Louisiana, November 2001. A major epidemiologic study found that high dietary intakes and blood levels of these xanthophyll carotenoids are correlated with a significantly lower risk of AMD, 12,13 but another study did not reach the same conclusion. 14 These inconsistent findings derive in part from the fact that blood levels and dietary intakes of lutein and zeaxanthin are relatively poor markers of the actual amounts present in the macula. 15 Clearly, it is of utmost importance to know the levels of lutein and zeaxanthin at their relevant site of action, the human macula. Recently, an autopsy study has reported that eyes from donors with a history of AMD had lower levels of macular carotenoids than eyes wi...

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Section: Discussionmentioning

confidence: 99%

Resonance Raman measurement of macular carotenoids in normal subjects and in age-related macular degeneration patients

et al. 2002

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“…Significant variation in the extent of UV filter-mediated modification of crystallins do, therefore, exist in our study population. We estimate, based on the molar absorptivity of GSH-3-OHKG (12) compared with the known increase in lenticular absorption of light at 360 nm (1), that at least 50% of the increase in age-related lenticular color in humans may be attributed to binding of 3-OHKG.…”

Section: Resultsmentioning

confidence: 99%

“…As part of the normal process of aging, the human lens becomes progressively more yellow and fluorescent (1-3), leading to a concomitant increase in light absorption in the 300 -500 nm range (1) and thus diminishes our perception of violet and blue light. The age-related increase in lens coloration and fluorescence is associated with the major proteins of the lens, the crystallins, and is particularly prominent in the lens nucleus (2,3).…”

mentioning

confidence: 99%

Human Lens Coloration and Aging

Hood

Garner

Truscott

1999

Journal of Biological Chemistry

108

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The human lens becomes increasingly yellow with age and thereby reduces our perception of blue light. This coloration is associated with lens proteins (crystallins), but its molecular basis was unknown. Here we show that the coloration occurs because of the interaction of crystallins with a UV filter compound, 3-hydroxykynurenine glucoside (3-OHKG). Crystallin modification results from deamination of the 3-OHKG amino acid side chain, yielding an unsaturated ketone that is susceptible to nucleophilic attack by cysteine, histidine, and lysine residues. This novel protein modification contributes to age-related lens coloration and may play a role in human nuclear cataractogenesis.As part of the normal process of aging, the human lens becomes progressively more yellow and fluorescent (1-3), leading to a concomitant increase in light absorption in the 300 -500 nm range (1) and thus diminishes our perception of violet and blue light. The age-related increase in lens coloration and fluorescence is associated with the major proteins of the lens, the crystallins, and is particularly prominent in the lens nucleus (2, 3). Because there is little or no protein turnover in the lens nucleus (4), the proteins are as old as the individual. The post-translational modifications that result in crystallin coloration, therefore, accumulate throughout life and may eventually contribute to age-related nuclear cataract. The latter condition is characterized by a brown coloration of the lens nucleus and extensive protein oxidation (5, 6). The human lens also contains a family of Trp-derived UV filter compounds, of which 3-OHKG 1 is present at the highest concentration (Ϸ500 M) (7, 8). These UV filters are thought to play a protective role by preventing potentially damaging UV light from reaching the retina. Several investigators have considered the possibility that the UV filters could covalently modify lens crystallins with deleterious consequences, including alteration of protein conformation and increased sensitivity to UV light (9 -11). However, the mechanism leading to crystallin modification by 3-OHKG was not determined nor was there any evidence that 3-OHKG induces protein modification in vivo.We have recently elucidated a novel pathway that leads to the formation of a glutathione (GSH) adduct of 3-OHKG in the human lens (12). The GSH-3-OHKG adduct was formed via deamination of the 3-OHKG amino acid side chain to form an ␣, ␤-unsaturated carbonyl that was highly susceptible to nucleophilic attack by the cysteine of GSH (12). The aim of the present studies is to assess the relevance of analagous reactions in the modification of crystallins and also to probe for evidence of crystallin-3-OHKG adducts in human lenses. EXPERIMENTAL PROCEDURESMaterials-All organic solvents were HPLC grade (Ajax, Unichrom, Auburn, NSW, Australia). Poly-L-lysine was from Sigma, trifluoroacetic acid (Ͼ99% pure) was from Aldrich, and acetic acid (Ͼ99.8% pure) from BDH (Poole, UK). 3-hydroxykynurenine O-␤-D-glucoside (3-OHKG) and 2-amino-3-hydroxyacetopheno...

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“…Exponential growth of the absorption was also reported in ref. [36]. Linear regression analysis leads to minimum MSE when the natural log of absorbance is used.…”

Section: Model Elements Of the Changing Eyementioning

confidence: 99%

Method for Adapting the Grayscale Standard Display Function to the Aging Eye

Ramponi

Badano

2016

J Digit Imaging

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Perceptual linearity of grayscale images based on a contrast sensitivity model is a widely recognized and used standard for medical imaging visualization. This approach ensures consistency across devices and provides perception of luminance variations in direct relationship to changes in image values. We analyze the effect of aging of the human eye on the precept of linearity and demonstrate that not only the number of just-noticeable differences diminishes for older subjects but also linearity across the range of luminance values is significantly affected. While loss of JNDs is inevitable for a fixed luminance range, our findings suggest possible corrective approaches for maintaining linearity.

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Age and the transmittance of the human crystalline lens.

Cited by 269 publications

References 18 publications

Resonance Raman measurement of macular carotenoids in normal subjects and in age-related macular degeneration patients

Resonance Raman measurement of macular carotenoids in normal subjects and in age-related macular degeneration patients

Human Lens Coloration and Aging

Method for Adapting the Grayscale Standard Display Function to the Aging Eye

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