Lens Model Research Articles

Clinical Outcomes after Implantation of a Novel Binocular Complementary Extended Depth-of-Focus Intraocular Lens Compared to Bilateral Low Near-Add Multifocal Intraocular Lenses

Introduction: Nowadays, patients expect to be less spectacle dependent at all distances after cataract surgery. However, all intraocular lens (IOL) models that currently offer this function can also have negative visual effects. Aim of this study was therefore to compare the visual function performance of a novel and a conventional IOL solution for multifocality. Methods: Patients scheduled for bilateral cataract surgery were randomized to receive one of two different IOL combinations: either a binocular complementary extended depth-of-focus IOL set or a low near-add MIOL. Patients had visual acuity (VA) assessment at distance, intermediate, and near as well as evaluation of contrast sensitivity, halometry, and reading performance. Results: In total, 56 eyes of 28 patients were enrolled. At 6 months, there were no statistically significant differences in binocular VA between the ARTIS SYMBIOSE and the AT LARA. Contrast sensitivity, measured binocularly, at 1.5 cycles per degree under photopic conditions without glare was 1.54 logCS with the ARTIS SYMBIOSE and 1.43 logCS with the AT LARA (p = 0.046), under mesopic conditions with glare at 1.5 and 3 cycles per degree 1.31 logCS and 1.28 logCS with the ARTIS SYMBIOSE, respectively, compared to 0.58 logCS and 0.51 logCS with the AT LARA (p = 0.002; p = 0.006). Binocular halos and reading performance between both groups were similar. Conclusion: There were no significant differences between both groups in VA at different distances, reading ability, or halometry. The contrast sensitivity at low spatial frequencies was better in the ARTIS SYMBIOSE group under photopic conditions without glare as well as mesopic conditions with glare, which could potentially improve quality of vision with these IOLs, especially under mesopic conditions.

The abundance of clustered primordial black holes from quasar microlensing

While elementary particles are the favored candidate for the elusive dark matter, primordial black holes (PBHs) have also been considered to fill that role. Gravitational microlensing is a very well-suited tool to detect and measure the abundance of compact objects in galaxies. Previous studies based on quasar microlensing exclude a significant presence of substellar to intermediate-mass black holes (BHs; $ 100M_ However, these studies were based on a spatially uniform distribution of BHs while, according to current theories of PBH formation, they are expected to appear in clusters. We study the impact of clustering in microlensing flux magnification, finding that at large scales clusters act like giant pseudo-particles, strongly affecting the emission coming from the broad-line region, which can no longer be used to define the zero microlensing baseline. As an alternative, we set this baseline from the intrinsic magnification ratios of quasar images predicted by macro lens models and compared them with the observed flux ratios in emission lines, infrared, and radio. The (magnitude) differences are the flux-ratio anomalies attributable to microlensing, which we estimate for 35 image pairs corresponding to 12 lens systems. A Bayesian analysis indicates that the observed anomalies are incompatible with the existence of a significant population of clustered PBHs. Furthermore, we find that more compact clusters exhibit a stronger microlensing impact. Consequently, we conclude that clustering makes the existence of a significant population of BHs in the substellar to intermediate mass range even more unlikely.

Birds of a Feather: Resolving Stellar Mass Assembly with JWST/NIRCam in a Pair of Kindred z ∼ 2 Dusty Star-forming Galaxies Lensed by the PLCK G165.7+67.0 Cluster

We present a new parametric lens model for the G165.7+67.0 galaxy cluster, which was discovered with Planck through its bright submillimeter flux, originating from a pair of extraordinary dusty star-forming galaxies (DSFGs) at z ≈ 2.2. Using JWST and interferometric mm/radio observations, we characterize the intrinsic physical properties of the DSFGs, which are separated by only ∼1″ (8 kpc) and a velocity difference ΔV ≲ 600 km s−1 in the source plane, and thus are likely undergoing a major merger. Boasting intrinsic star formation rates SFRIR = 320 ± 70 and 400 ± 80 M ⊙ yr−1, stellar masses of log[M⋆/M⊙]=10.2±0.1 and 10.3 ± 0.1, and dust attenuations of A V = 1.5 ± 0.3 and 1.2 ± 0.3, they are remarkably similar objects. We perform spatially resolved pixel-by-pixel spectral energy distribution (SED) fitting using rest-frame near-UV to near-IR imaging from JWST/NIRCam for both galaxies, resolving some stellar structures down to 100 pc scales. Based on their resolved specific star formation rates (SFRs) and UVJ colors, both DSFGs are experiencing significant galaxy-scale star formation events. If they are indeed interacting gravitationally, this strong starburst could be the hallmark of gas that has been disrupted by an initial close passage. In contrast, the host galaxy of SN H0pe has a much lower SFR than the DSFGs, and we present evidence for the onset of inside-out quenching and large column densities of dust even in regions of low specific SFR. Based on the intrinsic SFRs of the DSFGs inferred from UV through far-infrared SED modeling, this pair of objects alone is predicted to yield an observable 1.1 ± 0.2 core-collapse supernovae per year, making this cluster field ripe for continued monitoring.

The Carousel Lens: A Well-modeled Strong Lens with Multiple Sources Spectroscopically Confirmed by VLT/MUSE

Over the past few years alone, the lensing community has discovered thousands of strong lens candidates, and spectroscopically confirmed hundreds of them. In this time of abundance, it becomes pragmatic to focus our time and resources on the few extraordinary systems, in order to most efficiently study the Universe. In this paper, we present such a system: DESI-090.9854-35.9683, a cluster-scale lens at z l = 0.49, with seven observed lensed sources around the core, and additional lensed sources further out in the cluster. From the number and the textbook configuration of the lensed images, a tight constraint on the mass potential of the lens is possible. This would allow for detailed analysis on the dark and luminous matter content within galaxy clusters, as well as a probe into dark energy and high-redshift galaxies. We present our spatially resolved kinematic measurements of this system from the Very Large Telescope Multi Unit Spectroscopic Explorer, which confirm five of these source galaxies (in ascending order, at z s = 0.962, 0.962, 1.166, 1.432, and 1.432). With previous Hubble Space Telescope imaging in the F140W and F200LP bands, we also present a simple flux-based lens model consisting of two power-law profiles that, for a cluster lens, well models the five lensed arc families with redshifts. We determine the mass to be M(< θ E) = 4.78 × 1013 M ⊙ for the primary mass potential. From the model, we extrapolate the redshift of one of the two source galaxies not yet spectroscopically confirmed to be at zs=4.52−0.71+1.03 .

Stokes Phenomena in Lensing

As lensing of coherent astrophysical sources, e.g., pulsars, fast radio bursts, and gravitational waves, becomes observationally relevant, the mathematical framework of Picard–Lefschetz theory has recently been introduced to fully account for wave optics effects. Accordingly, the concept of lensing images has been generalized to include complex solutions of the lens equation referred to as “imaginary images,” and more radically, to the Lefschetz thimbles, which are a sum of the steepest descent contours connecting the real and imaginary images in the complex domain. In this wave-optics-based theoretical framework of lensing, we study the “Stokes phenomena” as the change of the topology of the Lefschetz thimbles. Similar to the well-known caustics at which the number of geometric images changes abruptly, the corresponding Stokes lines are the boundaries in the parameter space where the number of effective imaginary images changes. We map the Stokes lines for a few lens models. The resulting Stokes line-caustics network represents a unique feature of the lens models. The observable signature of the Stokes phenomena is the change of interference behavior, in particular the onset of frequency oscillation for some Stokes lines. We also demonstrate high-order Stokes phenomena where the system has a continuous number of effective images but with an abrupt change in the way they are connected to each other by the Lefschetz thimbles. Their full characterization calls for an analogy of the catastrophe theory for caustics.

Gravitational lensing reveals cool gas within 10-20 kpc around a quiescent galaxy

While quiescent galaxies have comparable amounts of cool gas in their outer circumgalactic medium (CGM) compared to star-forming galaxies, they have significantly less interstellar gas. However, open questions remain on the processes causing galaxies to stop forming stars and stay quiescent. Theories suggest dynamical interactions with the hot corona prevent cool gas from reaching the galaxy, therefore predicting the inner regions of quiescent galaxy CGMs are devoid of cool gas. However, there is a lack of understanding of the inner regions of CGMs due to the lack of spatial information in quasar-sightline methods. We present integral-field spectroscopy probing 10–20 kpc (2.4–4.8 Re) around a massive quiescent galaxy using a gravitationally lensed star-forming galaxy. We detect absorption from Magnesium (MgII) implying large amounts of cool atomic gas (108.4–109.3 M⊙ with T~104 Kelvin), in comparable amounts to star-forming galaxies. Lens modeling of Hubble imaging also reveals a diffuse asymmetric component of significant mass consistent with the spatial extent of the MgII absorption, and offset from the galaxy light profile. This study demonstrates the power of galaxy-scale gravitational lenses to not only probe the gas around galaxies, but to also independently probe the mass of the CGM due to it’s gravitational effect.

Functional Design Analysis of Two Current Extended-Depth-of-Focus Intraocular Lenses.

To evaluate the differences between two extended depth-of-focus intraocular lenses, the Alcon IQ Vivity and the Bausch & Lomb LuxSmart and to compare them with a simple monofocal lens, the Alcon IQ, using a simulation-based approach. A mathematical lens model was created for each lens type based on a measured surface geometry. The lens model was then used in a raytracer to calculate a refractive power map of the lens and a ray propagation image for the focal zone. The simulations confirm the enhanced depth of focus of these two lenses. There are apparent differences between the models. For the Vivity, more light is directed into the far focus in low light conditions, whereas the LuxSmart behaves more pupil independent and prioritizes intermediate vision. The simulation-based approach was effective in evaluating and comparing the design aspects of these lenses. It can be positioned as a valuable third tool for lens characterization, complementing in vivo studies and in vitro measurements. With this approach not only focusing on the resulting optical performance, but the underlying functional mechanisms, it paves the way forward for a better adaptation to the individual needs and preferences of patients.

Weak gravitational lensing around dyonic ModMax black hole in plasma

In this study, we examine the effects of weak gravitational lensing and determine the shadow radius around black holes within the Dyonic ModMax (DM) spacetime, also accounting for models with nonuniform plasma distributions. By analyzing various gravitational lens models, we compare corrections to vacuum lensing due to gravitational effects within plasma and plasma inhomogeneity, finding that these effects could be observed in hot gas within galaxy clusters. Starting with the orbits of photons around a black hole in DM, we investigate the shadow and weak gravitational lensing phenomena. Utilizing observational data from the Event Horizon Telescope for M87* and SgrA*, we constrain parameters within DM gravity. To connect our findings to observations, we examine the magnification and positioning of lensed images, along with the weak deflection angle and magnification for sources near different galaxies.

PyMOE: Mask design and modeling for micro optical elements and flat optics

We introduce a new open-source software package written in Python to design and model micro optical elements, such as diffractive lenses, holograms, as well as other components within the broad area of flat optics, and generate their corresponding (production-ready) lithography mask files. To this aim, the package provides functions to design a multitude of kinoform lenses, phase masks and holograms, but is versatile and the user can implement any arbitrary numerical or analytical optical component designs. For validating the designs, this package provides scalar diffraction propagation to simulate optical field propagation in different regimes covering near- and far-field regions (Fresnel, Fraunhofer and Rayleigh-Sommerfeld). Particularly, by implementing Rayleigh-Sommerfeld propagation, we demonstrate accurate field propagation within near- and far-field ranges, providing versatility and accuracy. Importantly, the package allows to directly export production-ready multilevel/binary lithography mask files of the designed optical components. Additionally, metasurface masks can conveniently be generated for any user-defined meta-element library given as input. Finally, the software package capabilities are illustrated with examples of mask design and modeling of diffractive lenses, holograms, and metasurfaces susceptible of being fabricated via lithography techniques. Beyond lithography, the package can also straightforwardly be used in other applications requiring mask generation, such as beam shaping, optical trapping and digital holography.

Weak lensing of strong lensing: beyond the tidal regime

The analysis of strong lensing images usually involves an external convergence and shear, which are meant to model the effect of perturbations along the line of sight, on top of the main lens. Such a description of line-of-sight perturbations supposes that the corresponding gravitational fields can be treated in the tidal regime. Going one step further introduces additional effects, known as flexion, which have been hitherto neglected in strong lensing. In this work, we build a minimal model for the line-of-sight flexion, which adds four new complex parameters to the lens model. Contrary to convergence and shear, the line-of-sight flexion cannot be projected onto the main lens plane. For a ΛCDM cosmology, we predict the typical line-of-sight flexion to be on the order of 10-3 arcsec-1 on galactic scales. Neglecting its effect in lens modelling is found to bias the recovery of other parameters; in particular, the line-of-sight shear can be biased up to 2σ. Accounting for the line-of-sight flexion in our minimal framework restores accuracy, at the cost of degrading precision. With current imaging capabilities, the line-of-sight flexion is unlikely to be measurable on individual strong lensing images; it must therefore be considered a nuisance parameter rather than an observable in its own right.

Objective analysis of capsulorrhexis factors and posterior capsular opacification in 420 postmortem eyes

ObjectiveTo evaluate the capsulorrhexis structure in postmortem eyes and determine factors associated with posterior capsular opacification (PCO). DesignExperimental study. ParticipantsPostmortem pseudophakic human eyes (n = 420). MethodsPostmortem eyes were obtained and examined. Photographs were taken of the eyes in Miyake-Apple view and of the extracted lens-capsule complexes. PCO and Soemmering's ring (SR) were quantified using automated detector opacification software as factors of intensity and area. Miyake-Apple views and ImageJ were used to assess capsulorrhexis diameter, area of anterior capsule-optic overlap, length of the shortest anterior capsular leaflet, and area and angle of capsulorrhexis-optic nonoverlap. Linear regression analysis and Welch's t test were used to determine the relationship of these factors with PCO and SR. All analyses were repeated in sample groups specific to the 5 most common intraocular lens models. ResultsCapsule-optic overlap was positively correlated with PCO (P < 0.0001) and SR (P = 0.0016). Capsulorrhexis diameter was negatively correlated with PCO (P < 0.0001) and SR (P = 0.014). Leaflet length was positively correlated with PCO (P = 0.009). Area and angle of capsulorrhexis-optic nonoverlap were not correlated with PCO or SR. Slopes and coefficients of determination were relatively low for all significant results. ConclusionsThe pathogenesis of PCO development after cataract surgery is multifactorial. This study shows that with modern operating technology, capsulorrhexis factors have at best a modest influence on PCO formation. Factors such as time from surgery to death and intraoperative techniques such as laser capsule polishing, posterior capsule vacuuming, and cortical cleanup are likely to play a more significant role.

El Gordo needs El Anzuelo: Probing the structure of cluster members with multi-band extended arcs in JWST data

Gravitational lensing by galaxy clusters involves hundreds of galaxies over a large redshift range and increases the likelihood of rare phenomena (supernovae, microlensing, dark substructures, etc.). Characterizing the mass and light distributions of foreground and background objects often requires a combination of high-resolution data and advanced modeling techniques. We present the detailed analysis of a prominent quintuply imaged dusty star-forming galaxy ($ mainly lensed by three members of the massive galaxy cluster ACT-CL\,J0102$-$4915, also known as d =0.87$). We leverage JWST/NIRCam images, which contain lensing features that were unseen in previous HST images, using a Bayesian, multi-wavelength, differentiable and GPU-accelerated modeling framework that combines (lens modeling) and (field model and inference) software packages. For one of the deflectors, we complement lensing constraints with stellar kinematics measured from VLT/MUSE data. In our lens model, we explicitly include the mass distribution of the cluster, locally corrected by a constant shear field. We find that the two main deflectors (L1 and L2) have logarithmic mass density slopes steeper than isothermal, with $ L1 and $ L2 We argue that such steep density profiles can arise due to tidally truncated mass distributions, which we probe thanks to the cluster lensing boost and the strong asymmetry of the lensing configuration. Moreover, our three-dimensional source model captures most of the surface brightness of the lensed galaxy, revealing a clump with a maximum diameter of $400$ parsecs at the source redshift, visible at wavelengths $ rest mu m. Finally, we caution on using point-like features within extended arcs to constrain galaxy-scale lens models before securing them with extended arc modeling.

Discrete magnification lens model: A new hybrid multi-scale modelling method for fluid-particle systems

We present a novel hybrid multi-scale model, referred to as “discrete magnification lens” method, which utilizes a computational fluid dynamics coupled to discrete element method (CFD-DEM) approach within a specific region of interest in a two-fluid model (TFM) simulation. We applied the discrete magnification lens to the crossing jet problem, where the TFM fails due to lack of considering bi-modal velocity distribution in its formulation. It was observed that adopting the discrete magnification lens, can effectively alter the non-physical behavior of the TFM to obey the behavior seen from CFD-DEM simulations. Moreover, the ability of the discrete magnification lens in reproducing particle clusters and improving the TFM predictions in case of unbounded fluidization simulations was further shown. We found that the discrete magnification lens can effectively enhance the TFM predictions in a complex fluid-particle system while requiring less numerical costs compared to the full-scale CFD-DEM simulations.

Complex optical systems for individualized correction of presbyopia

Amultitude of available intraocular lens (IOL) models enable apersonalized approach to presbyopia correction in order to meet each patient's needs. This review article discusses more complex approaches which can be useful in selected cases. The concept of reversible trifocality enables correction of presbyopia using asupplementary intraocular lens (IOL), which can be removed if necessary (e.g., intolerance to multifocal optics). The use of capsulotomy-fixated IOLs enables high precision for positioning of the lens and better stability compared to conventional capsular bag-fixated IOLs, which can be particularly advantageous in multifocal optics. The mix and match concept enables acombination of different IOLs with various optical principles to achieve the desired binocular effect. Binocular IOL systems, which consist of two complementary IOLs, can be seen as afurther development of the mix and match concept. Knowledge of the available options and their application can further improve correction of presbyopia.

‘LinkedIn, LinkedIn on the screen, who is the greatest and smartest ever seen?’: A machine learning approach using valid LinkedIn cues to predict narcissism and intelligence

AbstractRecruiters routinely use LinkedIn profiles to infer applicants' individual traits like narcissism and intelligence, two key traits in online network and organizational contexts. However, little is known about LinkedIn profiles' predictive potential to accurately infer individual traits. According to Brunswik's lens model, accurate trait inferences depend on (a) the presence of valid cues in LinkedIn profiles containing information about users' individual traits and (b) the sensitive and consistent utilization of valid cues. We assessed narcissism (self‐report) and intelligence (aptitude tests) in a sample of 406 LinkedIn users along with 64 LinkedIn cues (coded by three trained coders) that we derived from trait theory and previous empirical findings. We used a transparent, easy‐to‐interpret machine learning algorithm leveraging practical application potentials (elastic net) and applied state‐of‐the‐art resampling techniques (nested cross‐validation) to ensure robust results. Thereby, we uncover LinkedIn profiles' predictive potential: (a) LinkedIn profiles contain valid information about narcissism (e.g. uploading a background picture) and intelligence (e.g. listing many accomplishments), and (b) the elastic nets sensitively and consistently using these valid cues attain prediction accuracy (r = .35/.41 for narcissism/intelligence). The results have practical implications for improving recruiters' accuracy and foreshadow potentials and limitations of automated LinkedIn‐based assessments for selection purposes.

AGEL: Is the Conflict Real? Investigating Galaxy Evolution Models Using Strong Lensing at 0.3 < z < 0.9

Observed evolution of the total mass distribution with redshift is crucial to testing galaxy evolution theories. To measure the total mass distribution, strong gravitational lenses complement the resolved dynamical observations that are currently limited to z ≲ 0.5. Here we present the lens models for a pilot sample of seven galaxy-scale lenses from the ASTRO3D Galaxy Evolution with Lenses (AGEL) survey. The AGEL lenses, modeled using HST/WFC3-F140W images with Gravitational Lens Efficient Explorer (GLEE) software, have deflector redshifts in the range 0.3 < z defl < 0.9. Assuming a power-law density profile with slope γ, we measure the total density profile for the deflector galaxies via lens modeling. We also measure the stellar velocity dispersions (σ obs) for four lenses and obtain σ obs from SDSS-BOSS for the remaining lenses to test our lens models by comparing observed and model-predicted velocity dispersions. For the seven AGEL lenses, we measure an average density profile slope of −1.95 ± 0.09 and a γ–z relation that does not evolve with redshift at z < 1. Although our result is consistent with some observations and simulations, it differs from other studies at z < 1 that suggest the γ–z relation evolves with redshift. The apparent conflicts among observations and simulations may be due to a combination of (1) systematics in the lensing and dynamical modeling; (2) challenges in comparing observations with simulations; and (3) assuming a simple power law for the total mass distribution. By providing more lenses at z defl > 0.5, the AGEL survey will provide stronger constraints on whether the mass profiles evolve with redshift as predicted by current theoretical models.

A Strongly Lensed Dusty Starburst of an Intrinsic Disk Morphology at a Photometric Redshift of z ph > 7

We present COSBO-7, a strong millimeter source known for more than 16 yr that just revealed its near-to-mid-IR counterpart with the James Webb Space Telescope (JWST). The precise pinpointing by the Atacama Large Millimeter/submillimeter Array on the exquisite NIRCam and MIRI images show that it is a background source gravitationally lensed by a single foreground galaxy, and the analysis of its spectral energy distribution by different tools is in favor of photometric redshift at z ph > 7. Strikingly, our lens modeling based on the JWST data shows that it has a regular disk morphology in the source plane. The dusty region giving rise to the far-IR-to-millimeter emission seems to be confined to a limited region to one side of the disk and has a high dust temperature of >90 K. The galaxy is experiencing starburst both within and outside of this dusty region. After taking the lensing magnification of μ ≈ 2.5–3.6 into account, the intrinsic star formation rate is several hundred M ⊙ yr−1 both within the dusty region and across the more extended stellar disk, and the latter already has >1010 M ⊙ of stars in place. If it is indeed at z > 7, COSBO-7 presents an extraordinary case that is against the common wisdom about galaxy formation in the early Universe; simply put, its existence poses a critical question to be answered: how could a massive disk galaxy come into being so early in the Universe and sustain its regular morphology in the middle of an enormous starburst?

Sp1149. I. Constraints on the Balmer L–σ Relation for H ii Regions in a Spiral Galaxy at Redshift z = 1.49 Strongly Lensed by the MACS J1149 Cluster

The luminosities (L) and velocity dispersions (σ) of the extinction-corrected Balmer emission lines of giant H ii regions in nearby galaxies exhibit a tight correlation (∼0.35 dex scatter). There are few constraints, however, on whether giant H ii regions at significant look-back times follow an L–σ relation, given the angular resolution and sensitivity required to study them individually. We measure the luminosities and velocity dispersions of Hα and Hβ emission from 11 H ii regions in Sp1149, a spiral galaxy at redshift (z) z = 1.49 multiply imaged by the MACS J1149 galaxy cluster. Sp1149 is also the host galaxy of the first-known strongly lensed supernova with resolved images, SN Refsdal. We employ archival Keck I OSIRIS observations, and newly acquired Keck I MOSFIRE and Large Binocular Telescope LUCI long-slit spectra of Sp1149. When we use the GLAFIC simply parameterized lens model, we find that the Hα luminosities of the H ii regions at z = 1.49 are a factor of 6.4−2.0+2.9 brighter than predicted by the low-redshift L–σ relation we measure from Very Large Telescope MUSE spectroscopy. If the lens model is accurate, then the H ii regions in Sp1149 differ from their low-redshift counterparts. We identify an H ii region in Sp1149 that is dramatically brighter (by 2.03 ± 0.44 dex) than our low-redshift L–σ relation predicts given its low velocity dispersion. Finally, the H ii regions in Sp1149 are consistent, perhaps surprisingly, with the z ≈ 0 star-forming locus on the Baldwin–Phillips–Terlevich diagram.

Caustic area biases and how to deal with them

Quadruply imaged strongly lensed point sources (quads) are routinely used for measurements of the expansion rate of the Universe with time delays. It has recently been suggested that any quad lens is subject to a Malmquist-like bias that causes the inferred area enclosed within the tangential caustic to be systematically underestimated, and that such a bias might translate into a corresponding bias on the expansion parameter. In this work we extended that analysis by also considering the effect of Eddington bias. We find that the sign and amplitude of the combined bias depend on the functional form of the caustic area distribution of the lens population and on the noise associated with the caustic area estimation process. Based on simulations, we estimate that the corresponding impact on $H_0$ is of the order of a percent or smaller. If the likelihood of the lensing data is known, then the bias can be accounted for when modelling the lens population. However, ignoring the criteria used to select a quad might lead to a bias at the lens modelling stage that causes the inferred caustic area to be overestimated. Such a bias disappears for lens models that are well constrained by the data.

The COSMOS-Web ring: In-depth characterization of an Einstein ring lensing system at z ∼ 2

Aims. We provide an in-depth analysis of the COSMOS-Web ring, an Einstein ring at z ≈ 2 that we serendipitously discovered during the data reduction of the COSMOS-Web survey and that could be the most distant lens discovered to date. Methods. We extracted the visible and near-infrared photometry of the source and the lens from more than 25 bands. We combined these observations with far-infrared detections to study the dusty nature of the source and we derived the photometric redshifts and physical properties of both the lens and the source with three different spectral energy distribution (SED) fitting codes. Using JWST/NIRCam images, we also produced two lens models to (i) recover the total mass of the lens, (ii) derive the magnification of the system, (iii) reconstruct the morphology of the lensed source, and (iv) measure the slope of the total mass density profile of the lens. Results. We find the lens to be a very massive elliptical galaxy at z = 2.02 ± 0.02 with a total mass within the Einstein radius of Mtot(&lt;θEin = (3.66 ± 0.36) × 1011 M⊙ and a total stellar mass of M⋆ = 1.37−0.11+0.14 × 1011 M⊙. We also estimate it to be compact and quiescent with a specific star formation rate below 10−13 yr. Compared to stellar-to-halo mass relations from the literature, we find that the total mass of the lens within the Einstein radius is consistent with the presence of a dark matter (DM) halo of total mass Mh = 1.09−0.57+1.46 × 1013 M⊙. In addition, the background source is a M⋆ = (1.26 ± 0.17) × 1010 M⊙ star-forming galaxy (SFR ≈ (78 ± 15) M⊙ yr) at z = 5.48 ± 0.06. The morphology reconstructed in the source plane shows two clear components with different colors. Dust attenuation values from SED fitting and nearby detections in the far infrared also suggest that the background source could be at least partially dust-obscured. Conclusions. We find the lens at z ≈ 2. Its total, stellar, and DM halo masses are consistent within the Einstein ring, so we do not need any unexpected changes in our description of the lens such as changing its initial mass function or including a non-negligible gas contribution. The most likely solution for the lensed source is at z ≈ 5.5. Its reconstructed morphology is complex and highly wavelength dependent, possibly because it is a merger or a main sequence galaxy with a heterogeneous dust distribution.