Lens Samples Research Articles

Refractive Index Measurement of Glass with Arbitrary Shape Based on Brewster’s Law and a Focusing Probe Beam

The refractive index is one of the most important parameters of optical glasses and has a significant effect on optical properties. The measurement of optical glasses, especially for optical elements such as lenses, is urgently needed. However, several presented methods require the immersion of the sample in liquid and provide indirect measurements, while others require structural parameters as priori knowledge, which is complex and time-consuming. In this study, a Brewster-Law-based direct and simple measurement method for the refractive index of glasses with arbitrary shapes is proposed, and a laser beam is focused on the surface of the sample as a probe. The incident angle of the chief ray is close to the Brewster angle. The reflected light is collected by an array detector. The refractive index is calculated from the minimum intensity position obtained with image processing. Additionally, a symmetric measurement scheme is proposed to improve the accuracy. Using these methods, a prism and four spherical lens samples with different refractive indices or radii of curvature are tested and error analyses are carried out. Results indicate that the accuracy can reach 10−4.

RNA sequencing and bioinformatics analysis of human lens epithelial cells in age-related cataract

BackgroundAge-related cataract (ARC) is the main cause of blindness in older individuals but its specific pathogenic mechanism is unclear. This study aimed to identify differentially expressed genes (DEGs) associated with ARC and to improve our understanding of the disease mechanism.MethodsAnterior capsule samples of the human lens were collected from ARC patients and healthy controls and used for RNA sequencing to detect DEGs. Identified DEGs underwent bioinformatics analyses, including Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses. Subsequently, reverse transcription quantitative RT-qPCR was used to validate the different expression levels of selected genes.ResultsA total of 698 up-regulated DEGs and 414 down-regulated DEGs were identified in ARC patients compared with controls by transcriptome analysis. Through GO and KEGG bioinformatics analysis, the functions of significantly DEGs and their possible molecular mechanisms were determined. Sequencing results were verified by RT-qPCR as being accurate and reliable.ConclusionsThis study identified several genes associated with ARC, which improves our knowledge of the disease mechanism.

Fast full-field modulation transfer function analysis for photographic lens quality assessment.

Full-field modulation transfer function (MTF) data based on the slanted-edge method can give useful insights on the performance of a photographic lens sample and its shortcomings. Decentering and other out-of-tolerance states are recognized easily. A process to derive accurate lens MTF from slanted-edge spatial frequency response measurements is presented, covering chart design and alignment, data capture by standard digital cameras, slanted-edge algorithm implementation requirements, sensor and chart MTF corrections, and also visualization of the results. It is demonstrated that the reliability of the measured MTF values is by far good enough to support automated quality assessment with a measurement accuracy of ≈0.02 MTF and repeatability of ≲0.005 up to 100 c/mm. The measured full-field MTF values provide an unambiguous numerical criterion for comparison with expectations based on lens design.

Static compression optical coherence elastography to measure the mechanical properties of soft contact lenses.

In this study, a novel method was developed for estimating the elastic modulus (Young's modulus) of soft contact lens materials using static compression optical coherence elastography. Using a commercially available spectral domain optical coherence tomography instrument, an experimental setup was developed to image a soft contact lens sample before and during compression with a known applied force, from which the lens material's mechanical properties can be derived. A semi-automatic segmentation method using graph-search theory and dynamic processing was used to trace the lens boundaries and to determine key structural changes within the images. To validate the method, five soft contact lens materials with a range of known elastic moduli and water contents were tested. The proposed method was successful in estimating the Young's modulus in the five different soft contact lens materials. It was demonstrated that the method provides highly repeatable measurements, with an intraclass correlation coefficient of >95%. The Young's modulus results were compared to published manufacturer data with no significant difference for four out of the five materials (p > 0.05). These results demonstrate that a static compression optical coherence tomography method can reliably measure the elastic modulus of soft contact lenses. This provides a methodology that can be used to explore in vitro contact lens mechanical properties, but more importantly, may also be extended to study the mechanical characteristics of in vivo or ex vivo tissue, provided that they can be imaged using OCT.

The velocity dispersion function of early-type galaxies and its redshift evolution: the newest results from lens redshift test

ABSTRACT The redshift distribution of galactic-scale lensing systems provides a laboratory to probe the velocity dispersion function (VDF) of early-type galaxies (ETGs) and measure the evolution of ETGs at redshift z ∼ 1. Through the statistical analysis of the currently largest sample of ETG gravitational lenses, we conclude that the VDF inferred solely from strong lensing systems is well consistent with the measurements of SDSS DR5 data in the local Universe. In particular, our results strongly indicate a decline in the number density of lenses by a factor of two and a 20 per cent increase in the characteristic velocity dispersion for the ETG population at z ∼ 1. Such VDF evolution is in perfect agreement with the ΛCDM paradigm (i.e. the hierarchical build-up of mass structures over cosmic time) and different from ‘stellar mass-downsizing’ evolutions obtained by many galaxy surveys. Meanwhile, we also quantitatively discuss the evolution of the VDF shape in a more complex evolution model, which reveals its strong correlation with the number density and velocity dispersion of ETGs. Finally, we evaluate if future missions such as LSST can be sensitive enough to place the most stringent constraints on the redshift evolution of ETGs, based on the redshift distribution of available gravitational lenses.

PyAutoLens: Open-Source Strong Gravitational Lensing

Strong gravitational lensing, which can make a background source galaxy appears multiple times due to its light rays being deflected by the mass of one or more foreground lens galaxies, provides astronomers with a powerful tool to study dark matter, cosmology and the most distant Universe. PyAutoLens is an open-source Python 3.6+ package for strong gravitational lensing, with core features including fully automated strong lens modeling of galaxies and galaxy clusters, support for direct imaging and interferometer datasets and comprehensive tools for simulating samples of strong lenses. The API allows users to perform ray-tracing by using analytic light and mass profiles to build strong lens systems. Accompanying PyAutoLens is the autolens workspace (see https://github.com/Jammy2211/autolens_workspace), which includes example scripts, lens datasets and the HowToLens lectures in Jupyter notebook format which introduce non experts to strong lensing using PyAutoLens. Readers can try PyAutoLens right now by going to the introduction Jupyter notebook on Binder (see https://mybinder.org/v2/gh/Jammy2211/autolens_workspace/master) or checkout the readthedocs (see https://pyautolens.readthedocs.io/en/latest/) for a complete overview of PyAutoLens's features.

Dark Energy Survey Year 3 results: Optimizing the lens sample in a combined galaxy clustering and galaxy-galaxy lensing analysis

We investigate potential gains in cosmological constraints from the combination of galaxy clustering and galaxy-galaxy lensing by optimizing the lens galaxy sample selection using information from Dark Energy Survey (DES) Year 3 data and assuming the DES Year 1 Metacalibration sample for the sources. We explore easily reproducible selections based on magnitude cuts in $i$-band as a function of (photometric) redshift, $z_{\rm phot}$, and benchmark the potential gains against those using the well established redMaGiC sample. We focus on the balance between density and photometric redshift accuracy, while marginalizing over a realistic set of cosmological and systematic parameters. Our optimal selection, the MagLim sample, satisfies $i < 4 \, z_{\rm phot} + 18$ and has $\sim 30\%$ wider redshift distributions but $\sim 3.5$ times more galaxies than redMaGiC. Assuming a wCDM model and equivalent scale cuts to mitigate nonlinear effects, this leads to $40\%$ increase in the figure of merit for the pair combinations of $\Omega_m$, $w$, and $\sigma_8$, and gains of $16\%$ in $\sigma_8$, $10\%$ in $\Omega_m$, and $12\%$ in $w$. Similarly, in LCDM we find an improvement of $19\%$ and $27\%$ on $\sigma_8$ and $\Omega_m$, respectively. We also explore flux-limited samples with a flat magnitude cut finding that the optimal selection, $i < 22.2$, has $\sim 7$ times more galaxies and $\sim 20\%$ wider redshift distributions compared to MagLim, but slightly worse constraints. We show that our results are robust with respect to the assumed galaxy bias and photometric redshift uncertainties with only moderate further gains from increased number of tomographic bins or the inclusion of bin cross-correlations, except in the case of the flux-limited sample, for which these gains are more significant.

Tightening weak lensing constraints on the ellipticity of galaxy-scale dark matter haloes

Cosmological simulations predict that galaxies are embedded into triaxial dark matter haloes, which appear approximately elliptical in projection. Weak gravitational lensing allows us to constrain these halo shapes and thereby test the nature of dark matter. Weak lensing has already provided robust detections of the signature of halo flattening at the mass scales of groups and clusters, whereas results for galaxies have been somewhat inconclusive. Here we combine data from five weak lensing surveys (NGVSLenS, KiDS/KV450, CFHTLenS, CS82, and RCSLenS, listed in order of most to least constraining) in order to tighten observational constraints on galaxy-scale halo ellipticity for photometrically selected lens samples. We constrain fh, the average ratio between the aligned component of the halo ellipticity and the ellipticity of the light distribution, finding fh = 0.303−0.079+0.080 for red lens galaxies and fh = 0.217−0.159+0.160 for blue lens galaxies when assuming elliptical Navarro-Frenk-White density profiles and a linear scaling between halo ellipticity and galaxy ellipticity. Our constraints for red galaxies constitute the currently most significant (3.8σ) systematics-corrected detection of the signature of halo flattening at the mass scale of galaxies. Our results are in good agreement with expectations from the Millennium Simulation that apply the same analysis scheme and incorporate models for galaxy–halo misalignment. Assuming these misalignment models and the analysis assumptions stated above are correct, our measurements imply an average dark matter halo ellipticity for the studied red galaxy samples of ⟨|ϵh|⟩ = 0.174 ± 0.046, where |ϵh| = (1 − q)/(1 + q) relates to the ratio q = b/a of the minor and major axes of the projected mass distribution. Similar measurements based on larger upcoming weak lensing data sets can help to calibrate models for intrinsic galaxy alignments, which constitute an important source of systematic uncertainty in cosmological weak lensing studies.

Crystalline Lens Vitamin C Levels in Cataract Surgical Patients

To determine the amount of Vitamin C in the lenses of Diabetic and Non-Diabetic Patients with Operable Cataract and ascertain association between Vitamin C levels and Blood Glucose, Glycated Haemoglobin and Intraocular pressure. Thirty Diabetic and Thirty Non-Diabetic Patients cataract surgical patients were matched for age and sex and selected for the study. Plasma fasting blood glucose and whole blood glycated Haemoglobin levels were determined by glucose oxidase enzymatic assay and immunodetection methods respectively. Cataractous lens samples obtained during surgery were weighed and homogenized in 10 volumes of phosphate buffer pH 7 and the resulting homogenate centrifuged at 18,000 g for 5 minutes at 4˚C, separated and supernatant stored at -80˚C. Vitamin C assay was carried out using commercial assay kits. Data was analyzed using SPSS version 23. Age range of participants was 55 - 83 years, with a mean of 66.7 ± 1.8 years. Mean Vitamin C levels in the Diabetic and Non-Diabetic groups were 49.5 μg/g ± 6.47 and 57.02 μg/g ± 8.0 respectively. Although the Non-diabetic group had higher levels of Vitamin C, the difference was not significant. Levels of Vitamin C found in both groups are much lower than what has previously been reported in Literature for clear lenses. There was negative association between Vitamin C and Glucose, Glycated Haemoglobin and Intraocular Pressure. Vitamin C supplementation may be useful in prolonging incidence of cataract in both aging and diabetic Nigerian populations. Larger study involving estimation of Vitamin C in both lens and Plasma samples is desirable.

Cosmology with gravitationally lensed repeating fast radio bursts

High-precision cosmological probes have revealed a small but significant tension between the parameters measured with different techniques, among which there is one based on time delays in gravitational lenses. We discuss a new way of using time delays for cosmology, taking advantage of the extreme precision expected for lensed fast radio bursts, which are short flashes of radio emission originating at cosmological distances. With coherent methods, the achievable precision is sufficient for measuring how time delays change over the months and years, which can also be interpreted as differential redshifts between the images. It turns out that uncertainties arising from the unknown mass distribution of gravitational lenses can be eliminated by combining time delays with their time derivatives. Other effects, most importantly relative proper motions, can be measured accurately and disentangled from the cosmological effects. With a mock sample of simulated lenses, we show that it may be possible to attain strong constraints on cosmological parameters. Finally, the lensed images can be used as galactic interferometer to resolve structures and motions of the burst sources with incredibly high resolution and help reveal their physical nature, which is currently unknown.

Degradation of connexin 50 protein causes waterclefts in human lens.

Cataracts are mainly classified into three types: cortical cataracts, nuclear cataracts, and posterior subcapsular cataracts. In addition, retrodots and waterclefts are cataract subtypes that cause decreased visual function. To maintain an orderly and tightly packed arrangement to minimize light scattering, adhesion molecules such as connexins and aquaporin 0 (AQP0) are highly expressed in the lens. We hypothesized that some main and/or subcataract type(s) are correlated with adhesion molecule degradation. Lens samples were collected from cataract patients during cataract surgery, and mRNA and protein expression levels were measured by real-time RT-PCR and western blotting, respectively. The mRNA levels of adhesion molecules were not significantly different among any cataract types. Moreover, AQP0 and connexin 46 protein expressions were unchanged among patients. However, connexin 50 protein level was significantly decreased in the lens of patients with WC cataract subtype. P62 and LC3B proteins were detected in the WC patients’ lenses, but not in other patients’ lenses. These results suggest that more research is needed on the subtypes of cataracts besides the three major types of cataract for tailor-made cataract therapy.

Simultaneous and Rapid Detection of Multiple Epimers and Isomers of Aspartyl Residues in Lens Proteins Using an LC-MS-MRM Method.

Traditionally, studies of post translational modifications (PTMs) by mass analysis have been limited to modifications such as deamidation and oxidation that have a mass shift. Although Asp isomerization is an important PTM, the selective detection of Asp isomers by mass spectrometry was originally thought to be impossible due to the identical mass of the isomers. The recent development of an LC-MS-based method has facilitated rapid and accurate quantitative analysis of Asp isomers in long-lived proteins; however, because the quantification is based on the extracted ion chromatogram acquired by an MS1 scan, this methodology is not always efficient for detecting extremely low-abundance peptides in complex biological samples. In this paper, we evaluated Asp isomer-containing peptides of αA-crystallin present in tryptic digests of human lens samples with different degrees of protein aggregation and different ages using LC coupled with multiple reaction monitoring (MRM). In a single analysis, the LC-MRM method enabled three tryptic peptides containing isomers of Asp58, Asp91/92, and Asp151 to be detected simultaneously. The extent of isomerization and epimerization of these specific Asp sites in αA-crystallin increased with the progress of α-crystallin aggregation. For the analysis of samples known to isomerize at specific Asp residues, MRM gives a more rapid, less laborious, and high-quality separation of Asp isomer-containing peptides relative to the previous MS1-based quantitative method.

Velocity Dispersions of Massive Quiescent Galaxies from Weak Lensing and Spectroscopy*

Abstract We use MMT spectroscopy and deep Subaru Hyper Suprime-Cam (HSC) imaging to compare the spectroscopic central stellar velocity dispersion of quiescent galaxies with the effective dispersion of the dark matter halo derived from the stacked lensing signal. The spectroscopic survey (the Smithsonian Hectospec Lensing Survey) provides a sample of 4585 quiescent galaxy lenses with measured line-of-sight central stellar velocity dispersion (σ SHELS) that is more than 85% complete for R &lt; 20.6, D n 4000 &gt; 1.5 and M ⋆ &gt; 109.5 M ⊙. The median redshift of the sample of lenses is 0.32. We measure the stacked lensing signal from the HSC deep imaging. The central stellar velocity dispersion is directly proportional to the velocity dispersion derived from the lensing σ Lens, . The independent spectroscopic and weak lensing velocity dispersions probe different scales, ∼3 kpc and ≳100 kpc, respectively, and strongly indicate that the observable central stellar velocity dispersion for quiescent galaxies is a good proxy for the velocity dispersion of the dark matter halo. We thus demonstrate the power of combining high-quality imaging and spectroscopy to shed light on the connection between galaxies and their dark matter halos.

Physical Properties of High Functional Contact Lenses with Hydrophilic Substance and Graphene Oxide Nanocolloids.

The purpose of this experiment is to evaluate the physical properties of contact lenses made by adding hydrophilic Hyaluronic acid (HA) and Methacrylic acid (MA) as additives and Graphene oxide nanocolloids. As a contact lens, AIBN (Azobisisobutyronitrile) was used as an initiator with HEMA (2-hydroxy methyl methacrylate) and EGDMA (ethylene glycol dimethacrylate) as a cross-linker. Hyaluronic acid (HA) and methacrylic acid (MA) were added at 5%, respectively. Graphene oxide nanocolloids were added at 0.1%, 0.3% and 0.5%, respectively. Each prepared contact lens was hydrated in 99% NaCl saline solution for 24 hours. And the basic physical properties of contact lenses were evaluated and compared. The refractive index of the sample with hyaluronic acid and MA added was 1.4390, which was not significantly different from that of the basic combination contact lens sample. When Graphene oxide nanocolloids, a nanomaterial, were added, the refractive index decreased with increasing amount of Graphene oxide nanocolloids from 1.4209 to 13959. In the case of water content, the sample with 5% Hyaluronic acid and MA added slightly increased to 41.01%. In the case of Graphene oxide nanocolloids added, 48.76%~53.56% of Graphene oxide nanocolloids were added. Especially, it was observed that the water content increased sharply in the 0.1% sample of Graphene oxide nanocolloids. When the amount of graphene oxide nanocolloids added to the contact lens material was increased, the refractive index, which is a basic physical property, gradually decreased as the contact lens material was added together with Hyaluronic acid, MA, and Graphene oxide nanocolloids added as a nanomaterial. The water content tended to increase gradually. Therefore, the combination of Graphene oxide and hydrophilicmaterials shows a synergistic effect of physical properties, which is considered to be suitable as a material for contact lenses.

Cosmological Model-independent Constraints on Spatial Curvature from Strong Gravitational Lensing and SN Ia Observations

Abstract Applying the distance sum rule in strong gravitational lensing (SGL) and SN Ia observations, one can provide an interesting cosmological model-independent method to determine the cosmic curvature parameter Ω k . In this paper, with the newly compiled data sets including 161 galactic-scale SGL systems and 1048 SN Ia data, we place constraints on Ω k within the framework of three types of lens models extensively used in SGL studies. Moreover, to investigate the effect of different mass lens samples on the results, we divide the SGL sample into three subsamples based on the center velocity dispersion of intervening galaxies. In the singular isothermal sphere (SIS) and extended power-law lens models, a flat universe is supported with an uncertainty of about 0.2, while a closed universe is preferred in the power-law lens model. We find that the choice of lens models and the classification of SGL data actually can influence the constraints on Ω k significantly.

Activation of Sirtuin1 by lyceum barbarum polysaccharides in protection against diabetic cataract

Ethnopharmacological relevanceLycium barbarum polysaccharide (LBP) extracted from the Lycium barbarum L. has been widely used to improve diabetes and its relative complications. However, the mechanisms have not fully understood. A recent study has demonstrated that LBP upregulates suituin 1 (SIRT1). ObjectiveThis study was to define the role of Sirt1 and its downstream signaling pathways in diabetic cataract using in vitro and in vivo models. Materials and methodsHuman lens epithelial cell line SRA01/04 cells were cultured under high glucose (HG) medium with treatment of LBP or vehicle. Cell viability, apoptosis, protein and/or mRNA levels of Sirt1, BAX, Bcl-2, active-caspase-3, FOXO1, p27 and acetylated p53 were measured. SIRT1 upregulated- and knocked-down cells were generated and tested in high glucose culture. Diabetes mellitus was induced in rats by streptozotocin injection. Body weight, blood glucose levels, lens transparency and retinal function were assessed and SIRT1, as well as the aforementioned biomarkers were measured using Western blotting and qPCR in the animal lens samples. ResultsThe results showed that HG decreased cell viability and LBP prevented the decrease. The reduced viability in HG cultured SRA01/04 cells was associated with increased levels of BAX, active caspase 3, FOXO1, p27, and p53 and decreased levels of SIRT1 and Bcl-2. Further experiments using sirt1 gene modulated cells showed that upregulation of Sirt1 improved viability, increase cell division as reflected by an increased proportion of S phase in the cell cycle, reduced the number of apoptotic cell death and suppressed p53 acetylation and caspase 3 activation. Opposite results were observed in SIRT1 knock-down cells. Treating diabetic animals with LBP reduced body weight loss and blood glucose content in diabetic animals. Similarly, LBP hindered the development of cataract in lenses and improved retinal function. The beneficial effect of LBP on diabetic cataract was associated with the supression of p53, caspase 3, FOXO1, BAX, p27 and elevation of SIRT1 and Bcl-2, which were consistent with the in vitro findings. ConclusionOur findings showed that diabetes caused cataract is associated with suppression of SIRT1 and Bcl-2 and activation of other cell death related genes. LBP prevented diabetic cataract in animals by upregulating Sirt1 and Bcl-2 and suppressing cell death related genes.

Observation of light rays on absolute geodesic lenses.

Absolute optical instruments with rotation symmetry and corresponding absolute geodesic lenses have drawn considerable attention for their property of perfect imaging of light rays. In this paper, we systematically explore a series of absolute geodesic lenses which is mapped from generalized Maxwell's fish-eye lenses with a rational number index {p}. Moreover, we construct new types of duplex absolute geodesic lenses by splicing two different half absolute geodesic lenses, which is inspired by the work [Huiyan Peng, et al Phys. Rev. Applied13, 034050 (2020)]. Also, we fabricate some samples of absolute geodesic lenses based on the 3D printing technique and observe light rays on them. Our findings enlarge the family of absolute geodesic lenses and might find an application on classical imaging systems.

The importance of magnification effects in galaxy-galaxy lensing

Magnification changes the observed local number density of galaxies on the sky. This biases the observed tangential shear profiles around galaxies: the so-called galaxy-galaxy lensing (GGL) signal. Inference of physical quantities, such as the mean mass profile of halos around galaxies, are correspondingly affected by magnification effects. We used simulated shear and galaxy data from the Millennium Simulation to quantify the effect on shear and mass estimates from the magnified lens and source number counts. The former is due to the large-scale matter distribution in the foreground of the lenses; the latter is caused by magnification of the source population by the matter associated with the lenses. The GGL signal is calculated from the simulations by an efficient fast Fourier transform, which can also be applied to real data. The numerical treatment is complemented by a leading-order analytical description of the magnification effects, which is shown to fit the numerical shear data well. We find the magnification effect is strongest for steep galaxy luminosity functions and high redshifts. For a KiDS+VIKING+GAMA-like survey with lens galaxies at redshift zd = 0.36 and source galaxies in the last three redshift bins with a mean redshift of ¯zs = 0.79, the magnification correction changes the shear profile up to 2%, and the mass is biased by up to 8%. We further considered an even higher redshift fiducial lens sample at zd = 0.83, with a limited magnitude of 22 mag in the r-band and a source redshift of zs = 0.99. Through this, we find that a magnification correction changes the shear profile up to 45% and that the mass is biased by up to 55%. As expected, the sign of the bias depends on the local slope of the lens luminosity function αd, where the mass is biased low for αd &lt; 1 and biased high for αd &gt; 1. While the magnification effect of sources is rarely more than 1% of the measured GGL signal, the statistical power of future weak lensing surveys warrants correction for this effect.

Light control elements as convex cylindrical lens and concave cylindrical mirror based on 2D high-index contrast gratings

Convex cylindrical lens and concave cylindrical mirror using 2D non-periodic high-index contrast gratings (HCGs) by introducing a parabolic cylinder phase front are proposed and numerically investigated, simulation results indicate that the transmitted or reflected light beam of the structures can be modulated by the grating blocks and will converge into a line of light or a linear spot on the image plane while maintaining high transmissivity or reflectivity with low polarization dependence. An HCG convex cylindrical lens sample with a focal length of 250 μm and a grating area of 400 μm × 400 μm are fabricated on an SOI wafer, which exhibits a liner focusing ability on the image side under normal incidence at the wavelength of 1.55 μm.

Asp isomerization increases aggregation of α-crystallin and decreases its chaperone activity in human lens of various ages

α-Crystallin, comprising 40–50 subunits of αA- and αB-subunits, is a long-lived major soluble chaperone protein in lens. During aging, α-crystallin forms aggregates of high molecular weight (HMW) protein and eventually becomes water-insoluble (WI). Isomerization of Asp in α-crystallin has been proposed as a trigger of protein aggregation, ultimately leading to cataract formation. Here, we have investigated the relationship between protein aggregation and Asp isomerization of αA-crystallin by a series of analyses of the soluble α-crystallin, HMW and WI fractions from human lens samples of different ages (10–76 years). Analytical ultracentrifugation showed that the HMW fraction had a peak sedimentation coefficient of 40 S and a wide distribution of values (10–450 S) for lens of all ages, whereas the α-crystallin had a much smaller peak sedimentation coefficient (10–20 S) and was less heterogeneous, regardless of lens age. Measurement of the ratio of isomers (Lα-, Lβ-, Dα-, Dβ-) at Asp58, Asp91/92 and Asp151 in αA-crystallin by liquid chromatography–mass spectrometry showed that the proportion of isomers at all three sites increased in order of aggregation level (α-crystallin < HMW < WI fractions). Among the abnormal isomers of Asp58 and Asp151, Dβ-isomers were predominant with a very few exceptions. Notably, the chaperone activity of HMW protein was minimal for lens of all ages, whereas that of α-crystallin decreased with increasing lens age. Thus, abnormal aggregation caused by Asp isomerization might contribute to the loss of chaperone activity of α-crystallin in aged human lens.