Pigment Density Research Articles

Halobacteria Formula Improvement of Skin Care-A Randomized, Double-Blind, Placebo-Controlled Clinical Study.

Halobacteria trueperi, an extremophilic microorganism thriving in high-salt environments, produces extracellular polysaccharides with potential anti-inflammatory and anti-aging properties. However, its clinical efficacy in skin improvement remains unclear. This study focuses on H. trueperi TCI66207, isolated from the Pacific Ocean at a depth of 662 m near Hualien, and its potential to enhance skin parameters, aiming to develop a novel functional formulation for pharmaceutical and cosmetic use. This sudy aims to evaluate the clinical efficacy of H. trueperi TCI66207 on various skin parameters and its potential for developing new functional cosmetic formulations. A total of 40 subjects were recruited and randomly divided into two groups: the test group applied a serum containing H. trueperi TCI66207, while the placebo group used a basic serum. Subjects were instructed to apply the serum twice daily for 4 weeks. Skin parameters, including moisture, brightness, elasticity, pigmentation (spots and UV spots), texture, wrinkles, pores, and collagen density, were assessed before and after the 4-week application period. After 4 weeks of using the H. trueperi TCI66207 serum, significant improvements were observed in all measured skin parameters compared to baseline, with notable enhancements in moisture, brightness, elasticity, texture, and collagen density, along with reductions in wrinkles, spots, and pore size. Halobacteria trueperi TCI66207 serum demonstrates a clear ability to improve skin conditions and delay signs of aging, making it a promising candidate for the development of new cosmetic formulations with potent anti-aging and skin-rejuvenating properties.

Dermoscopy of Lichen Planus Pigmentosus and Histopathological Correlation: A Case Series

Introduction: Lichen planus pigmentosus (LPP) is an acquired pigmentary disorder affecting the dark-skinned population. There is a wide range of differentials with substantial clinicopathological overlap. Dermoscopy may contribute to the better characterization of this dermatosis. Objective: This study aimed to describe dermoscopic features of LPP with a histopathological correlation. Methods: LPP lesions of 23 patients were studied using a polarized dermoscopy, followed by histological evaluation. Results: The most common dermoscopic finding was dots and/or globules (n=23) in different patterns: speckled (n=4), dotted (n=2), reticular (n=4), diffuse (n=9), hem-like (n=1), and circular (n=2). Other patterns were exaggerated pseudo-reticular pattern (n=12), sparing of follicular openings (n=23), targetoid appearance (n=3), blue-white veil (n=5), rosettes (n=5), erythema (n=4), and telangiectasia (n=7). Histological findings included pigment incontinence (n=23), the severity being mild (n=8) and severe (n=15). We found a statistically significant association between the intensity of pigmentary incontinence on the histological examination and the presence of blotches in dermoscopy (p=0.046); and between blue-white veil and rosettes in flexural areas (p=0.01). Also, a statistical relationship was found between severe pigment density (reticulated and diffused patterns) and a short disease duration (p=0.016). Conclusion: We described LPP dermoscopic changes according to disease progression. We found that blotches are indicative of long-duration disease and could be specific dermoscopic features of LPP. We demonstrated that a blue-white veil associated with rosettes could be pathognomonic features of LPP inversus.

A clinical case of successful treatment of the dry form of age-related macular degeneratio

the clinical case is an example of the effectiveness of low-energy pulsed chromatic LED therapy of green (505 nm), red (625 nm) and infrared (940 nm) ranges in the treatment of dry age-related macular degeneration, which was performed with the Spektra Light device (Version MARK III, Vision AidInc., Canada). The patient was examined before treatment, 1 month, 3 months and 6 months after treatment: visual acuity was determined, optical coherence tomography of the macular zone was performed, and the optical density of the macular pigment of both eyes was determined by heterochromatic flicker photometry using a Maculux praxis densitometer (Germany, Ebiga VISION GmbH). In a patient with age-related macular degeneration, after two short-term courses (2 sessions per day with a 5-minute break for 5 days) of low-energy LED therapy, visual acuity increased, the optical density of the macular pigment increased, and positive dynamics was noted in the scans of optical coherence tomography of the macular zone of the retina.

Physicochemical and Color Changes During Fruit Ripening in Pepper Species (C. annuum L., C. baccatum L., and C. chinense Jacq.) Exposed to Salt Stress

This study examines the impact of salt stress on the physicochemical and color characteristics of three pepper species (Capsicum annuum L., Capsicum baccatum L., and Capsicum chinense Jacq.) at different ripening periods. Peppers were exposed to 0 mM, 50 mM, and 100 mM NaCl during the green, breaking, and red ripening periods. The results showed that salt stress significantly influenced moisture content, total ash, pH, titratable acidity, water activity, and color parameters. C. chinense had the highest moisture content and water activity, while C. annuum demonstrated a higher total ash content and pigment density (ASTA value). As fruits ripened, moisture content decreased, and total ash content increased. Salt stress caused reductions in water activity, pH, and titratable acidity, with high salt concentrations leading to increased water loss and a decline in fruit quality. Furthermore, salt stress reduced color parameters and ASTA values, indicating suppressed carotenoid pigment synthesis. The study highlights the importance of developing salt-tolerant pepper varieties, as salt stress negatively impacts the physiological and biochemical quality of peppers. These findings suggest that appropriate agronomic strategies and careful environmental monitoring are essential for sustainable pepper production, particularly in areas with saline soils. The results provide valuable insights into the mechanisms through which salt stress affects pepper fruit quality and suggest avenues for improving crop resilience.

Bilberry Extract in Macular Pigment Density Improvement

Macular Pigments (MPs), by absorbing potentially toxic short-wavelength (400–500 nm) visible light, provide protection against photo-chemical damage. A new method of MPs levels screening analyzes polarization-dependent absorption of blue light by MPs, which results in the entoptic phenomenon called Haidinger’s Brushes (HB). Subjects identify the direction of rotation of HB when presented with a circular stimulus illuminated with an even intensity of polarized white light in which the electric field vector was rotating either clockwise or anti-clockwise. The examination was performed at baseline and after 3 months of daily intake of 320 mg bilberry extract, from Vaccinium myrtillus L. and standardized to contain more than 36% of anthocyanins (anthocyanosides), in normal subjects and MPs improvement was recorded after 3 months of dietary supplements. The results suggest a challenging role of daily intake of 320 mg bilberry extract in macular pigment density improvement possibly due to a macular protection from oxidative damage by bilberry.

Individual differences in color matches and cone spectral sensitivities in 51 young adults.

Forty-six young adult observers with normal color vision (plus five from an earlier study) made a series of color matches using a new LED-based, multi-wavelength visual trichromator. Thirteen LED lights of different wavelengths were combined to produce 11 triplets of lights that observers were asked to match to a white reference light of 7500 K over visual angles of either 2° or 10°. Matches were initially made by asking observers to adjust the intensities of the three lights making up each triplet. As the experiment progressed, a more intuitive matching procedure was developed. By transforming the triplet of lights into CIELAB space, observers adjusted colors using lightness (L*), redness-greenness (a*), and blueness-yellowness (b*) to make the match with white. The new procedure proved easier for observers and reduced the inter- and intra-observer variability. Given that each of the 11 matches to the reference white for a given observer (obtained by either method) should produce identical L-, M- and S-cone excitations, we were able to use the matches to infer the individual cone spectral sensitivities for each observer and thus estimate the range of individual differences across our 51 observers. By applying a model of the CIEPO06 standard LMS observer, the photopigment, macular and lens optical densities and the L- and M-cone photopigment spectral shifts that best equated the three-cone excitations across the 11 matches were found for each observer. The individual differences were consistent with the CIEPO06 observer except for a 3 nm shift of the M-cone photopigment to longer wavelengths and a slightly denser 2-deg macular pigment density.

Macular Pigment Assessment in Indian Population Using Degree of Polarization Threshold: Impact of Diet on Macular Pigment Density.

To determine macular pigment (MP) density scores in healthy Indians and examine correlations with demographic and lifestyle variables. We observed 484 Indians without an ocular pathology. Body mass index (BMI) and self-reported lifestyle factors (sunglasses usage, physical activity, and smoking) were noted. MP density was assessed as the threshold of perception of the shadow of their macular pigments on their retina using a new MP assessment tool (MP-eye). Lutein and zeaxanthin intake was assessed using a prevalidated questionnaire regionally designed for the Indian diet. Clusters of participants were created for statistical analysis based on MP-eye scores secondarily to detect any relevant effects in very low, low, medium, and high ranges of MPs. Data analyzed included 235 males and 249 females with mean age of 36.1 ± 12.9 years (range, 14-72). The median MP-eye score was 6 (range, 0-10, with 10 being high). Most were non-smokers (413, 85.3%) and did not use sunglasses (438, 90.5%), and 314 (64.9%) had low physical activity. Diabetes was present in 62 participants (12.8%) and hypertension in 53 (10.9%). Advancing age (r = -0.209; P < 0.000) and BMI (r = -0.094; P = 0.038) had weak negative correlation with MP-eye scores. Hypertension was less prevalent (7/88) in the cluster with the highest median MP-eye score (P = 0.033). Dietary intake of MPs and other lifestyle factors did not correlate significantly with MP-eye score overall or when analyzed in clusters. MP-eye scores of an Indian population were normally distributed. Higher age, high BMI, and presence of hypertension were weakly associated with lower MP-eye scores. The impact of diet on MPs requires further evaluation. This normative regional database enables risk stratification of macular degeneration.

Seasonal patterns of phytoplankton photoacclimation in a dimictic oligotrophic lake over 5 yr: Implications for chlorophyll as an estimate of biomass

AbstractChlorophyll a is commonly used as a surrogate for algal biomass in lakes and oceans even though phytoplankton can readily adjust intracellular chlorophyll concentration to changes in the environment through a cellular process termed photoacclimation. Marine studies have documented fluctuations in cellular chlorophyll to year‐round changes in light intensity and nutrients using the chlorophyll : carbon ratio to estimate cellular pigment density. However, similar freshwater studies are almost exclusively limited to chlorophyll : carbon ratios at the summertime deep chlorophyll maximum (DCM) depth in less productive water. This study expands direct estimates of freshwater photoacclimation to all seasons of the year utilizing optically derived estimates of algal carbon and chlorophyll fluorescence from high‐frequency (daily) data. We describe patterns of photoacclimation at daily, seasonal, and interannual time scales over a 5‐yr period. We show that increases in chlorophyll density at the cellular level not only occurred at the DCM depth during summer stratification but were a dominant and recurring feature when the lake was vertically mixing in fall, winter, and spring. Pigment density within the mixed layer was negatively correlated with light level, indicating a photoacclimation driven response to reduced light intensity. Predicting how cellular pigment density is affected by the surrounding environment in a replicated range of lake systems is needed if chlorophyll is to be accurately used as an estimate of algal biomass in freshwaters.

Effect of light intensity and seal type on the in vitro elongation and adventitious rooting of Eucalyptus grandis × E. urophylla

Background: Rejuvenation/reinvigoration of tissues through micropropagation has become an important tool for clonal propagation in eucalypts species. This study evaluated the effect of photomixotrophism (i.e., light intensity and seal type) on in vitro elongation and adventitious rooting to identify the limiting factors on in vitro culture of the Eucalyptus grandis × E. urophylla hybrid. Methods: Nodal segments (i.e., explants) from ministumps grown in a semi-hydroponic system were collected. The effects of light intensity and seal type on in vitro elongation and adventitious rooting stages were evaluated from a 40 μmol m-2 s-1 fluorescent lamp and 20, 40, and 80 μmol m-2 s-1 red/blue LEDs, with (through porous membranes) and without gas exchange. Results: Based on the results at 35 d, 40 μmol m-2 s-1 fluorescent lamp and gas exchange combination was the most suitable for in vitro elongation and adventitious rooting of Eucalyptus grandis × E. urophylla. Both factors increased the vigour, shoot length, photosynthetic pigment content, xylem, phloem, stomatal number and density, root length, diameter, number of roots per explant, and adventitious rooting fraction. Conclusions: Light intensity and seal type influences the in vitro elongation and adventitious rooting of Eucalyptus grandis × E. urophylla. The results contribute to optimising the cloning of commercial eucalypts species by the micropropagation technique.

Measuring the visual angle of polarization-related entoptic phenomena using structured light.

The ability to perceive polarization-related entoptic phenomena arises from the dichroism of macular pigments held in Henle's fiber layer of the retina and can be inhibited by retinal diseases, such as age-related macular degeneration, which alters the structure of the macula. Structured light tools enable the direct probing of macular pigment density and retinal structure through the perception of polarization-dependent entoptic patterns. Here, we directly measure the visual angle of an entoptic pattern created through the illumination of the retina with a structured state of light and a perception task that is insensitive to corneal birefringence. The central region of the structured light stimuli was obstructed, with the size of the obstruction varying according to a psychophysical staircase. Two stimuli, one producing 11 azimuthal fringes and the other three azimuthal fringes, were presented to 24 healthy participants. The pattern with 11 azimuthal fringes produced an average visual angle threshold of 10° ± 1° and a 95% confidence interval (C.I.) of [6°, 14°]. For the pattern with three azimuthal fringes, a threshold extent of 3.6° ± 0.3° C.I. = [1.3°, 5.8°] was measured, a value similar to the published extent of Haidinger's brush (4°). The increase in apparent size and clarity of entoptic phenomena produced by the presented structured light stimuli offers the potential to detect the early signs of macular disease over perception tasks using uniform polarization stimuli.

Изменение оптической плотности макулярного пигмента на фоне различной тампонады витреальной полости в хирургии пролиферативной диабетической ретинопатии

Purpose. To determine dynamic changes of macular pigment optical density against the background of vitreal cavity tamponade with gas-air mixture and silicone oil during vitreoretinal intervention for proliferative diabetic retinopathy. Material and methods. 82 patients (82 eyes) with proliferative diabetic retinopathy were included in the study. The patients were divided into 2 groups: the first group consisted of 38 patients (38 eyes), who underwent vitrectomy with gas-air tamponade of vitreal cavity (16% hexafluoroethane C2F6, Acreole (ARCAD)), second group – 44 patients (44 eyes) with similar scope of surgery and silicone oil tamponade of vitreal cavity (5700 cSt, Oxane 10ml Syringe (Bausch&amp;Lomb)). Control examinations with determination of macular pigment optical density were performed before treatment, 1, 3 and 6 months after vitreoretinal interventions. The observation period was 6 months. Results. In 1 month after vitreoretinal intervention in the first group of patients there was a significant increase in the optical density of macular pigment in 1.1 times, in the second group – in 1.26 times, respectively (p &lt; 0.01 in comparison with the data before treatment). After 3 months, there was an increase of this index by 1.07 times in the first group, with its decrease by 1.02 times in patients of the 2nd group (p &lt;0.01 compared with data 1 month after surgery). In 6 months after surgical treatment, the average macular pigment optical density increased 1.5 times in first group (p &lt;0.01 compared with data before surgery) and was 1.09 times higher compared with the results obtained in the second study group (p&lt;0.01). This parameter also significantly increased in second group of patients by 1.43 times (p &lt;0.01 to the data before surgery). Conclusion. After vitreoretinal intervention, in all cases there was a significant increase average index of macular pigment optical density, regardless of the used tamponade of the vitreal cavity. However, in the group with gas-air tamponade, this parameter was significantly higher in comparison with the data obtained in the group with silicone oil tamponade, and after its removal.

Effect of pre‐receptor filters on chromatic sensitivity and other visual functions in the eye

Spatial and spectral information carried by light emitted from visual displays is filtered as it passes through spectacle lenses in front of the eye as well as by filters within the eye. The image forming and the spectral transmittance properties of the elements involved in image formation in the eye cause changes in both the luminance and colour contrast in retinal images. In addition, the amount of light that reaches the retina is always reduced by pre‐receptor filters and this reduction in retinal illuminance can cause diminished retinal sensitivity to both luminance and colour contrast. Of particular interest are the use of coloured lenses in front of the eye to reduce the short‐wavelength content of the light that reaches the retina and the use of ‘notch’ filters to absorb light selectively in certain wavebands, with inevitable consequences on both the luminance and chromatic contrast of retinal images. The presence of variant cone‐pigments in some subjects or the complete absence of one class of cone pigment in others, can also produce large deviations in both luminance and colour contrast signals that can either enhance or diminish the conspicuity of coloured objects (doi: 10.1364/josaa.22.000017).The purpose of this study was to develop and validate a model of red/green (RG) and yellow/blue (YB) colour discrimination that can also predict how chromatic sensitivity is affected by the use of spectrally‐selective, spectacle lenses or by filters internal to the eye, when viewing visual displays. We examined how RG and YB colour thresholds relate to the corresponding cone contrasts needed for detection of colour differences. The results reveal an invariance of cone contrasts at threshold for different states of chromatic adaptation. In other words, colour contrast signals at threshold follow Weber's law (doi: 10.1111/j.1475‐1313.2010.00773.x). A combination of RG and YB colour signals is needed to predict the colour threshold ellipse. The model relies on these findings and predicts how coloured filters external to the eye as well as pre‐receptor filters within the eye alter the measured RG and YB colour thresholds. Model predictions have been compared against measured colour thresholds using the CAD test (doi: 10.1093/bmb/ldx007). A number of experiments were carried out when the visual display was viewed with no lens in front of the eye or through a number of tinted lenses designed to absorb progressively more blue light.The effects of pre‐receptor filters within the eye such as the lens and the macular pigment have also been investigated. The results show that ‘blue‐blocking’ filters employed in typical spectacle lenses used with daylight illumination cause only small shifts, approximately along the daylight locus, without any significant loss of either RG or YB chromatic sensitivity. ‘Orange’ lenses that absorb greater amounts of short‐wavelength light cause a significant increase in YB thresholds, but have little or no effect on RG thresholds. More surprisingly, the model also predicts that the optical density of the macular pigment has little or no effect on the size of the colour threshold ellipse.Keywords: colour, cone contrasts, blue light, CAD test.

Optimization, a Potential Production, GC-MS and Characterization of Dark Green Pigment from New Local Isolate Streptomyces nigra Strain GH12

Due to increasing health awareness among consumers and the identification of novel pharmacological properties of diverse natural pigments, the market for natural pigments is currently seeing rapid growth. Streptomyces. nigra GH12, a new Actinomycete isolate identified by 16S rRNA used for dark green pigment production. Manipulations of the factors affecting pigment production are the most effective way to have maximum yield of pigment. Starch 2.5% (w/v), ammonium nitrate 0.2% (w/v), dibasic sodium phosphate 0.1% (w/v), inoculums size 6% (v/v), initial pH level of 8, 150 rpm rotation speed, 37 ºC temperature, and 9 days of incubation were found the optimum growth conditions for the highest green pigment production. The extraction of green pigment was performed efficiently with ethanol solvent. Results showed no effect on the pigment content at 40, 50 and 60°C. On heating pigment extract at 70, 80, 90 and 100oC for 60 min, retention of pigment remained as high as 97.4, 93, 86 and 79% of the total pigment density , respectively, even with continuous treatment at 100°C for more 60 min. The results indicated that the pigment extracts exhibited their greatest stabilities at high pH values, i.e. 8.0, 8.5, 9.0 and 10.0, during the entire holding time. The pigment was characterized by full UV-visible spectroscopic screening, where the potential absorption maximum of the target green pigment extract was recorded in the range of 300 ̶ 360 nm, with a λmax at 340 nm. Moreover, the chemical composition diversity of the pigment extract was further investigated by GC/MS analysis that revealed the presence of 57 metabolites in their silylated form.

Influence of macular pigment on the sensitivity to discomfort glare from daylight

Understanding the factors that influence the human perception of glare is necessary to properly address glare risks in buildings and achieve comfortable visual environments, especially in the workplace. Yet large inter-individual variabilities in glare perception remain unexplained and thus uncovered by the current empirical glare models. We hypothesize that this variability has an origin in the human retina, in particular in the density of macular pigments present in its central area, which varies between individuals. Macular pigments are known to absorb blue light and attenuate chromatic aberration, thus reducing light scatter. This study presents the outcomes of the first experiment ever conducted in a daylit office environment, in which glare sensitivity and macular pigment density were measured and compared for 110 young healthy individuals, along with other ocular parameters. The participants were exposed to different glare conditions induced by the sun filtered through either color-neutral or blue-colored glazing. In neutral daylight conditions with sun disc in the near periphery, neither macular pigment nor any other investigated ocular factors have an impact on discomfort glare perception whereas glare perception in conditions with the blue-colored sun disc in the near periphery was found to be correlated with macular pigment optical density.

Methods for Optimizing the Content of VOCs to Create Environmentally Friendly Materials for Protective Coatings

In order to successfully reduce the emission of toxic organic solvents harmful to human health and the environment during the application and curing of paints and varnishes (VPM), ways to create environmentally friendly organically soluble VPM "SB" and water-dispersed VPM "WB" are proposed. The influence of the values of dry residues in solutions of organic oligomers and the density of the components of pigmented materials on the values of the content of volatile organic compounds (VOC) for different types of materials has been studied. Mathematical analysis of situations with the addition and reduction of the amount of solvents allowed to set the limit values of the amount of solvents in varnishes for "SB" materials with different densities and VOC = 300 g/l. The influence of volumetric concentration of pigments, dry residue of varnishes and density of pigments and fillers on the VOC content in materials has been studied. The ratios of VPM components have been optimized and formulations of environmentally friendly materials have been developed.

Absorption Spectra as Predictors of Algal Biomass and Pigment Content of the Cultured Microalgae Amphidinium carterae, Isochrysis galbana, Nephroselmis sp., and Anabaena sp.

Background: In the search of a rapid and representative method for the approximate calculation of culture density and cell content of useful pigments, the study of absorption spectra of cultures of the dinoflagellate Amphidinium carterae, the haptophyte Isochrysis galbana, the chlorophyte Nephroselmis sp., and the filamentous cyanobacterium Anabaena sp. were selected as representative species of different taxa. Methods: The experimental cultures were established in small volumes by the discontinuous method under 20–21 °C, salinity of 30 or 40 ppt, and 2000 or 8000 lux illumination, and the absorbance spectra, density of the culture and concentration of the extracted pigments chlorophyll, total carotenoids, and phycocyanin were recorded during cultivation. Results: Algal density can be predicted sufficiently correctly because the regression equation of the correlation of the OD value of 750 nm from each absorption spectrum and the measured algal biomass was very strong. The same is true for the corresponding correlations between OD 750 nm and the detected pigments. Conclusions: Absorption spectra of microalgal cultures can be a simple, inexpensive, and non-invasive method for the growers to obtain the necessary information for predicting the right time to collect an ideal combination of maximum biomass and useful pigments, provided that the interpretation of the spectra is performed according to the method described herein.

Roles of macular carotenoids in brain function throughout the lifespan: A review of recent research

Lutein, zeaxanthin, and meso-zeaxanthin are carotenoids stored in the macular pigment of the retina, recognized for their essential role in maintaining optimal eye health. These carotenoids contribute to increased macular pigment density, providing protection against oxidative damage to the retina. Recent studies have unveiled potential cognitive health benefits of lutein and zeaxanthin, as they act as antioxidants in neural tissue. This review aims to comprehensively assess the current research investigating the effects of lutein and zeaxanthin on cognitive and macular function across various stages of life. During infancy and childhood, lutein and zeaxanthin are thought to facilitate the development of the eyes and brain, although the precise underlying mechanisms remain incompletely understood. In adulthood and older age, lutein and zeaxanthin assume a protective role for both brain and macular tissues. Their antioxidant properties effectively shield these tissues from oxidative stress and consequent damage. Consequently, lutein and zeaxanthin play crucial supportive and protective roles throughout an individual's lifespan.

Aspacochioside C from Asparagus cochinchinensis attenuates eumelanin synthesis via inhibition of TRP2 expression

Aspacochioside C (ACC) is a steroidal saponin isolated from Asparagus cochinchinensis. Steroidal saponins, such as pseudoprotodioscin and dioscin, are known to inhibit melanogenesis, but the role of ACC in melanogenesis remains unknown. Due to the toxic effect of the commonly used skin whitening agents like arbutin, kojic acid and α-lipoic acid alternative plant products are recentlybeen studied for their anti-hypergmentation effect. This study explores the role of ACC in melanogenesis in both in vivo and in vitro models. Here, we for the first time demonstrate that ACC attenuated α-MSH- and UVB-induced eumelanin production by inhibiting tyrosinase-related protein (TRP)-2 protein expression in both murine B16F10 and human melanoma MNT1 cells. However, ACC had no significant effect on pheomelanin concentration. ACC also decreased the pigmentation density in zebrafish embryos, which indicates that ACC targets TRP2 and inhibits eumelanin synthesis. Our results demonstrate that ACC inhibits TRP2, thereby attenuating eumelanin synthesis both in in vitro and in vivo zebrafish model. Therefore, ACC can potentially be used as an anti-melanogenic agent for both aesthetic and pharmaceutical purposes.

Positive Association between Macular Pigment Optical Density and Glomerular Filtration Rate: A Cross-Sectional Study.

Although decreased macular pigment density is associated with the development of age-related macular degeneration (AMD), exactly how this decrease may contribute to the development of AMD is still not fully understood. In this study, we investigated the relationship between macular pigment optical density (MPOD) and estimated glomerular filtration rate (eGFR). MPOD was measured using MPS II (Electron Technology, Cambridge, UK) in 137 participants who showed no clinical signs of AMD at 3 months after cataract surgery, and simple and multiple linear regression analyses were performed to determine the associations with age, sex, abdominal circumference, diabetes, hypertension, smoking, intraocular lens color, visual acuity before and after surgery, and eGFR. The participants were divided into two groups based on the median MPOD (0.58): the high-pigment and low-pigment groups. The mean value of eGFR in the high-pigment group was significantly higher than that in the low-pigment group (64.2 vs. 58.1, p = 0.02). The simple linear regression analysis revealed a significant positive association between MPOD and eGFR (β = 0.0034, 95% confidence interval [CI]: 0.0011-0.0056, p = 0.0038), and this association was independent of age, sex, abdominal circumference, diabetes, smoking, hypertension, best-corrected visual acuity (BCVA) before surgery, BCVA after surgery, and intraocular lens color (β = 0.0033, 95% CI: 0.00090-0.0058, p = 0.0076). These results show a strong association of renal dysfunction with the decrease in MPOD.

Formulae for generating standard and individual human cone spectral sensitivities.

Normal color perception is complicated. But at its initial stage it is relatively simple, since at photopic levels it depends on the activations of just three photoreceptor types: the long- (L-), middle- (M-) and short- (S-) wavelength-sensitive cones. Knowledge of how each type responds to different wavelengths-the three cone spectral sensitivities-can be used to model human color vision and in practical applications to specify color and predict color matches. The CIE has sanctioned the cone spectral sensitivity estimates of Stockman and Sharpe (Stockman and Sharpe, 2000, Vision Res) and their associated measures of luminous efficiency as "physiologically-relevant" standards for color vision (CIE, 2006; 2015). These LMS cone spectral sensitivities are specified at 5- and 1-nm steps for mean "standard" observers with normal cone photopigments and average ocular transparencies, both of which can vary in the population. Here, we provide formulae for the three cone spectral sensitivities as well as for macular and lens pigment density spectra, all as continuous functions of wavelength from 360 to 850 nm. These functions reproduce the tabulated discrete CIE LMS cone spectral sensitivities for 2-deg and 10-deg with little error in both linear and logarithmic units. Furthermore, these formulae allow the easy computation of non-standard cone spectral sensitivities (and other color matching functions) with individual differences in macular, lens and photopigment optical densities, and with spectrally shifted hybrid or polymorphic L- and M-cone photopigments appropriate for either normal or red-green color vision deficient observers.