Customized Reconstruction of Lower Eyelid Defects.

BACKGROUND: A lower eyelid defect is a loss of skin, muscle, and underlying structures that can occur due to trauma, malignant or benign tumors, burns, or other causes. The conventional surgical treatment of lower lid defects has several limitations, including visible scarring, narrowing of the eye, and ectropion. Here, we combined the use of a customized mid-face lift with a free mucochondral graft to overcome the disadvantages of existing methods. METHODS: Forty patients underwent reconstructive surgery using a customized mid-face lift with or without a free mucochondral graft for a lower lid defect between April 2013 and October 2020. Patients were discharged shortly after surgery and were expected to visit the outpatient clinic periodically for 12 months. RESULTS: The causes of lower eyelid defects were malignancy, trauma, foreign body granuloma, and other causes. Four patients reported complications, including 2 cases of chemosis, 1 case of a hematoma, and 1 case of corneal abrasion, who reportedly performed well after 2 weeks of conservative therapy. No patient required revision during the average follow-up period. CONCLUSIONS: Customized reconstruction demonstrated a better aesthetic reconstruction of the lower eyelid. This method represents a good option for reconstructing lower lid defects.

Aberration Theory of a Flat, Aplanatic Metalens Doublet and the Design of a Meta-Microscope Objective Lens.

A theoretical approach for reducing multiple monochromatic aberrations using a flat metalens doublet is proposed and verified through ray tracing simulations. The theoretical relation between the Abbe sine condition and the generalized Snell's law is revealed in the doublet system. Starting from the Abbe aplanat design, minimization conditions of astigmatism and field curvature are derived. Based on the theory, a metalens doublet is semi-analytically optimized as a compact, practical-level meta-microscope objective lens working for a target wavelength. The proposed approach also reveals how to reduce lateral chromatism for an additional wavelength. The design degree of freedom and fundamental limits of the system are both rigorously analyzed in theory and verified through ray tracing simulations. It is expected that the proposed method will provide unprecedented practical opportunities for the design of advanced compact microscopic imaging or sensing systems.

Aesthetic Removal of Foreign Body Granulomas of Forehead Via Pretrichial Approach.

ABSTRACT: In the field of plastic surgery, various filler types have been developed, which are widely used for cosmetic or reconstruction purposes. However, unregulated substances often injected by unlicensed practitioners may cause difficult-to-treat side effects, such as foreign body granulomas. Since the forehead is an exposed area and the lesions are likely extensive, complete surgical removal with inconspicuous scar can be difficult. In addition, pharmacological treatments, such as steroids, have only a temporary effect. The authors report successful cases of foreign body removal combined with subcutaneous forehead lift via a pretrichial approach for cosmetic satisfaction.Ten patients who had received illegal filler injections that resulted in chronic granulomas on the forehead were studied. The granulomas were confirmed using sonography, and simultaneous foreign body removal and subcutaneous forehead lifts using pretrichial incisions were planned. For the surgical method, the forehead flap was carefully elevated to a uniform thickness in the subcutaneous plane via a pretrichial incision, and the foreign body was removed, paying attention to the forehead contour and nerve damage; excess skin was excised from the top of the flap to tighten the remaining skin on the forehead.None of the patients developed complications, such as skin necrosis, infection, hematoma, or wound dehiscence, during the follow-up period. The functional and aesthetic outcomes were satisfactory in all the patients.The subcutaneous forehead lift via a pretrichial incision seems to facilitate foreign body removal and improve the forehead deformity by tightening the remaining skin.

Dielectric Metalens: Properties and Three-Dimensional Imaging Applications.

Recently, optical dielectric metasurfaces, ultrathin optical skins with densely arranged dielectric nanoantennas, have arisen as next-generation technologies with merits for miniaturization and functional improvement of conventional optical components. In particular, dielectric metalenses capable of optical focusing and imaging have attracted enormous attention from academic and industrial communities of optics. They can offer cutting-edge lensing functions owing to arbitrary wavefront encoding, polarization tunability, high efficiency, large diffraction angle, strong dispersion, and novel ultracompact integration methods. Based on the properties, dielectric metalenses have been applied to numerous three-dimensional imaging applications including wearable augmented or virtual reality displays with depth information, and optical sensing of three-dimensional position of object and various light properties. In this paper, we introduce the properties of optical dielectric metalenses, and review the working principles and recent advances in three-dimensional imaging applications based on them. The authors envision that the dielectric metalens and metasurface technologies could make breakthroughs for a wide range of compact optical systems for three-dimensional display and sensing.

Full-Color-Tunable Nanophotonic Device Using Electrochromic Tungsten Trioxide Thin Film.

Color generation based on strategically designed plasmonic nanostructures is a promising approach for display applications with unprecedented high-resolution. However, it is disadvantageous in that the optical response is fixed once the structure is determined. Therefore, obtaining high modulation depth with reversible optical properties while maintaining its fixed nanostructure is a great challenge in nanophotonics. In this work, dynamic color tuning and switching using tungsten trioxide (WO3), a representative electrochromic material, are demonstrated with reflection-type and transmission-type optical devices. Thin WO3 films incorporated in simple stacked configurations undergo dynamic color change by the adjustment of their dielectric constant through the electrochromic principle. A large resonance wavelength shift up to 107 nm under an electrochemical bias of 3.2 V could be achieved by the reflection-type device. For the transmission-type device, on/off switchable color pixels with improved purity are demonstrated of which transmittance is modulated by up to 4.04:1.

Tauroursodeoxycholic Acid Decreases Keloid Formation by Reducing Endoplasmic Reticulum Stress as Implicated in the Pathogenesis of Keloid.

Keloids are a common form of pathologic wound healing and are characterized by an excessive production of extracellular matrix. This study examined the major contributing mechanism of human keloid pathogenesis using transcriptomic analysis. We identified the upregulation of mitochondrial oxidative stress response, protein processing in the endoplasmic reticulum, and TGF-ß signaling in human keloid tissue samples compared to controls, based on ingenuity pathway and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses. Electron microscopic examinations revealed an increased number of dysmorphic mitochondria and expanded endoplasmic reticulum (ER) in human keloid tissue samples than that in controls. Western blot analysis performed using human tissues suggested noticeably higher ER stress signaling in keloids than in normal tissues. Treatment with tauroursodeoxycholic acid (TUDCA), an ER stress inhibitor, significantly decreased scar formation in rabbit models, compared to normal saline and steroid injections. In summary, our findings demonstrate the contributions of mitochondrial dysfunction and dysregulated ER stress signaling in human keloid formation and the potential of TUDCA in the treatment of keloids.

Doublet metalens design for high numerical aperture and simultaneous correction of chromatic and monochromatic aberrations.

Metalens is one of the most prominent applications among metasurfaces since it gives possibilities to replace the conventional lenses for compactness and multi-functionalities. Recently, many studies have been demonstrated to overcome the aberrations of the metalenses for high performance practical applications. Previous studies have used the methods that control the dispersion of meta-atoms for correcting chromatic aberrations and use doublet platform for correcting monochromatic aberrations. Despite these studies and the large demands for simultaneous correction of the aberrations in high numerical aperture metalens, the simultaneous correction has not been demonstrated yet. In this paper, we report the doublet metalens design with high numerical aperture which corrects longitudinal chromatic aberration and four monochromatic aberrations including spherical aberration, coma, astigmatism, and field curvature simultaneously for the three primary visible colors. Based on the novel doublet platform, the multi-wavelength targeted correction lens and geometric phase lens with color filtering functionality are utilized. Our doublet metalens has numerical apertures of 0.33, 0.38, and 0.47 for 445 nm, 532 nm, and 660 nm, respectively. The back focal length of our doublet metalens remains nearly 360 µm for target wavelengths and incident angles up to 30 degrees.

In Vitro and in Vivo Biocompatibility and Degradability Evaluation of Modified Polydioxanone Plate.

BACKGROUND: Polydioxanone (PDS) has been widely used in the medical field over the past 30 years. In the 2000s, PDS plate began to be used for rhinoplasty and septoplasty. However, in Asia PDS plates are not widely used due to lack of awareness and high prices. The authors devised a method of producing a modified PDS (m-PDS; Rhinoblock Material & Design Co., Gyeonggi-do, Sothh Korea) at low cost, and compared the biocompatibilities and degradabilities of plates produced with m-PDS and commercial PDS plates (Ethicon, Somerville, NJ) in vivo and in vitro. METHODS: The melting point and decomposition rate of m-PDS were determined by differential scanning calorimetry and thermogravimetric analysis and its tensile strength was also measured. Implants (1 cm × 1 cm × 0.15 mm sized) were inserted subcutaneously into mice and harvested en bloc 2, 5, 10, 15, or 25 weeks later. Tissues were stained with hematoxylin and eosin or Masson's trichrome to evaluate inflammation, extracellular matrix deposition, and vascularization, and plate degradability was also assessed. RESULTS: No significant difference was observed between the thermal analysis and tensile test results of m-PDS and PDS plates. m-PDS started to degrade in vivo from around 10 weeks, and commercial PDS plates from around 15 weeks. After 25 weeks in vivo, both products were completely degraded and not observed in tissue slides. Histologic analysis of excised specimens showed m-PDS and PDS were similar in terms of inflammation, extracellular matrix deposition, and vascularization. CONCLUSION: In vivo and in vitro experiments detected no significant difference between the biocompatibilities and degradabilities of modified and commercial PDS plates. The results of this study suggest that the modified PDS can be used to produce versatile, low cost, absorbable graft materials for rhinoplasty and septoplasty.

Simultaneous control of polarization and amplitude over broad bandwidth using multi-layered anisotropic metasurfaces.

In this paper, the broadband transmissive modulation of polarization and amplitude is demonstrated with high efficiency and tunability using multi-layered aluminum metasurfaces. Broadband and nondispersive optical rotation in the optical frequency region is realized by using Fabry-Pérot-like cavity and phase compensation. Simultaneously, the transmission amplitude can be independently controlled by adjusting the twist angle of the anisotropic metasurfaces. The proposed polarization-amplitude modulators are numerically demonstrated to achieve large tunability with an amplitude modulation depth of 0.95 and maximum rotation angle of 180°.

Electrically tunable multifunctional metasurface for integrating phase and amplitude modulation based on hyperbolic metamaterial substrate.

Active metasurfaces, which are tunable and reconfigurable nanophotonic structures with active materials, have been in spotlight as a versatile platform to control the profiles of scattered light. These nanoscale structures show surpassing functionalities compared to the conventional metasurfaces. They also play an important role in a wide range of applications for imaging, sensing, and data storage. Hence, the expansion of functionalities has been highly desired, in order to overcome the limited space constraints and realize the integration of several optical devices on a single compact platform. In this context, an electrically tunable metasurface that enables respective modulation of the phase and amplitude of reflected light, depending on the angle of incidence at the targeted wavelength, is proposed. This resonance-based device with hyperbolic metamaterial substrate excites different kinds of highly confined modes, according to the incident angle. Indium tin oxide is employed to offer electrically tunable optical properties in the near-infrared regime. At the wavelength of 1450 nm, the proposed device modulates the phase of reflected light with ~207 degrees of modulation depth for normal incidence, whereas it shows ~86% of relative reflectance change for oblique incidence of 60 degrees. In principle, the proposed scheme might provide a path to applications for the next-generation ultracompact integrated systems.

Plasmonic metasurface cavity for simultaneous enhancement of optical electric and magnetic fields in deep subwavelength volume.

It has been hard to achieve simultaneous plasmonic enhancement of nanoscale light-matter interactions in terms of both electric and magnetic manners with easily reproducible fabrication method and systematic theoretical design rule. In this paper, a novel concept of a flat nanofocusing device is proposed for simultaneously squeezing both electric and magnetic fields in deep-subwavelength volume (~λ3/538) in a large area. Based on the funneled unit cell structures and surface plasmon-assisted coherent interactions between them, the array of rectangular nanocavity connected to a tapered nanoantenna, plasmonic metasurface cavity, is constructed by periodic arrangement of the unit cell. The average enhancement factors of electric and magnetic field intensities reach about 60 and 22 in nanocavities, respectively. The proposed outstanding performance of the device is verified numerically and experimentally. We expect that this work would expand methodologies involving optical near-field manipulations in large areas and related potential applications including nanophotonic sensors, nonlinear responses, and quantum interactions.

Broadband efficient modulation of light transmission with high contrast using reconfigurable VO2 diffraction grating.

Ultra-compact dynamically reconfigurable modulation of optical transmission has been widely studied by using subwavelength-spaced resonant metasurface structures containing reconfigurable optical materials. However, it has been difficult to achieve high transmissivity, large modulation depth, and broad bandwidth simultaneously with the conventional resonance-based metasurface schemes. Here, we propose a reconfigurable phase-transition diffractive grating, made of thick VO2 ridge waveguides, for achieving the above-mentioned three goals simultaneously in the near-infrared range. Based on the large dielectric-to-plasmonic transition characteristic of VO2 in the near-infrared range, diffraction directivity of dual-VO2 ridge waveguide is designed to be tuned by thermally driven phase transition of VO2 for transverse electrically polarized illumination. Then, the diffractive VO2 ridge waveguide grating composed of the periodically arranged dual VO2 ridge waveguides is designed with on-state efficiency around 0.3 and minimum modulation depth about 0.35 over a broad bandwidth of 550 nm (1100-1650 nm). The working principle and excellent modulation performance are thoroughly verified through numerical and experimental studies.

Critical nanofocusing of magnetic dipole moment using a closed plasmonic tip.

Squeezing magnetic dipole (MD) moment into a deep subwavelegnth apex of a tapered tip has not been achieved so far owing to a specific mode volume of a MD resonance which is dependent on an operating wavelength and back reflection of nanofocused waves. We propose a novel strategy for efficient delivery and nanofocusing of optical MD at an apex of a closed resonant plasmonic tip. Due to the ultracompact area (~λ2/900) of the nanocavity and resonances assisted by partial mirrors in a plasmonic waveguide, the enhancement factor of magnetic energy density is improved over 5 times. We expect that our scheme can help to investigate strong magnetic phenomena, including enhanced magnetic transition, artificial optical magnetism, multipole nonlinear optics, biomolecular sensing, magnetic near-field imaging, and spectroscopy.

Broadband ultrathin circular polarizer at visible and near-infrared wavelengths using a non-resonant characteristic in helically stacked nano-gratings.

Modern imaging and spectroscopy systems require to implement diverse functionalities with thin thickness and wide wavelength ranges. In order to meet this demand, polarization-resolved imaging has been widely investigated with integrated circular polarizers. However, the circular polarizers which operate at the entire visible wavelengths and have a thickness of several tens of nanometers have not been developed yet. Here, a circular polarizer, operating at the entire visible wavelength range, is demonstrated using helically stacked aluminum nano-grating layers. High extinction ratio and broad operation bandwidth are simultaneously achieved by using non-resonant anisotropic characteristics of the nano-grating. It is theoretically verified that the averaged extinction ratio becomes up to 8 over the entire visible wavelength range while having a thickness of 390 nm. Also, the feasibility of the proposed structure and circular polarization selectivity at the visible wavelength range are experimentally verified. It is expected that the proposed structure will lead to extreme miniaturization of a circular polarizer and contribute greatly to the development of mobile/wearable imaging systems such as virtual reality and augmented reality displays.

Metamaterials and Metasurfaces for Sensor Applications.

Electromagnetic metamaterials (MMs) and metasurfaces (MSs) are artificial media and surfaces with subwavelength separations of meta-atoms designed for anomalous manipulations of light properties. Owing to large scattering cross-sections of metallic/dielectric meta-atoms, it is possible to not only localize strong electromagnetic fields in deep subwavelength volume but also decompose and analyze incident light signal with ultracompact setup using MMs and MSs. Hence, by probing resonant spectral responses from extremely boosted interactions between analyte layer and optical MMs or MSs, sensing the variation of refractive index has been a popular and practical application in the field of photonics. Moreover, decomposing and analyzing incident light signal can be easily achieved with anisotropic MSs, which can scatter light to different directions according to its polarization or wavelength. In this paper, we present recent advances and potential applications of optical MMs and MSs for refractive index sensing and sensing light properties, which can be easily integrated with various electronic devices. The characteristics and performances of devices are summarized and compared qualitatively with suggestions of design guidelines.

See-through multi-projection three-dimensional display using transparent anisotropic diffuser.

We propose a see-through multi-projection three-dimensional (3D) display using a transparent anisotropic diffuser. By immersing a metal-coated anisotropic diffuser into index matching oil which has the same refractive index of anisotropic diffuser, a transparent anisotropic diffuser is implemented. The reflectance of the transparent anisotropic diffuser is analyzed with the transfer matrix. Two multi-projection methods are proposed based on reflection type integral imaging and multi-view method. Especially, the reflection type multi-view-based system is realized with a curved anisotropic diffuser. High resolution see-through 3D display can be realized with the proposed methods. They can be used in various applications with the two multi-projection methods. In order to show the augmented reality features, real objects and virtual 3D images are presented at the same time in the experimental setup.

The Effect of Botulinum Toxin A on the NADPH Oxidase System and Ischemia-Reperfusion Injury.

BACKGROUND: Despite the increasing popularity of various materials for ischemia-reperfusion (I/R) injury mitigation, research on botulinum toxin type A (BoNTA) remains limited. This study assesses BoNTA's efficacy in protecting flaps from I/R injury by inhibiting the nicotinamide adenine dinucleotide phosphate (NADPH) oxidase system and reducing reactive oxygen species (ROS) production. METHODS: Seventy-six Sprague-Dawley rats were studied. We examined the effects of BoNTA on superoxide production in four rats using a lucigenin-enhanced chemiluminescence assay (LECL). Another group of 60 rats had their superficial inferior epigastric artery (SIEA) flaps treated with either BoNTA or saline and clamped for 0, 1, and 4 hours before reperfusion. Flap survival and histological outcomes were assessed five days post-operation. ROS production in SIEA flaps and femoral vessels was analyzed in 12 additional rats, post-I/R injury. RESULTS: The LECL results showed that the BoNTA group had significantly lower superoxide production compared to controls, with notable reductions at 4 hours. While no significant differences were noted at the 0 and 1-hour marks, the 4-hour mark showed significant protective effects in BoNTA-treated groups. The survival rate was 90% for BoNTA-treated rats versus 60% for controls ( P = 0.028). Significant reductions in ROS were also observed in the 4-hour I/R group. CONCLUSIONS: BoNTA effectively protects against I/R injury by inhibiting the NADPH oxidase system and reducing ROS levels. These results support further investigation into the specific mechanisms of NADPH oxidase inhibition by BoNTA and its potential clinical applications, given its safety profile. CLINICAL RELEVANCE STATEMENT: The findings from the present study are expected to provide a basis for clinical studies regarding this use of BoNTA.

Mandible Angle Resection with the Retroauricular Approach.

Square-shaped and large moon-shaped faces are commonly observed in Asians, and the contour of the mandible is associated with the shape of the lower part of the face. Mandible contouring surgery is performed to create a softer impression for East Asians. Currently, most surgeries are performed using an intraoral approach. External approaches have not been cosmetically attempted because of possible damage to the facial nerve and visible scarring and have been limited to mandible bone fracture reduction. This study included 42 patients who underwent mandibular angle reduction via classical intraoral incision and retroauricular incision between April 2019 and October 2021. Clinical outcomes were assessed using the Global Aesthetic Improvement Scale and Visual Analog Scale. Surgery was successful in all cases, with no significant complications. An appropriate mandibular contour was achieved postoperatively. All patients were satisfied with the outcome. Some patients experienced short-term complications, such as hematoma and wound disruption of the skin above the incision line. However, these improved within 3 weeks, and no serious long-term complications were observed. Mandible angle resection with the retroauricular approach is a promising alternative for patients, allowing speedy recovery and the resumption of routine daily life.

Smartphone-Based LiDAR Application for Easy and Accurate Wound Size Measurement.

The accurate assessment of wound size is a critical step in advanced wound care management. This study aims to introduce and validate a Light Detection and Ranging (LiDAR) technique for measuring wound size. Twenty-eight wounds treated from December 2022 to April 2023 at the Chungnam National University Hospital were analyzed. All the wounds were measured using three techniques: conventional ruler methods, the LiDAR technique, and ImageJ analysis. Correlation analysis, linear regression, and Bland-Altman plot analysis were performed to validate the accuracy of the novel method. The measurement results (mean ± standard deviation) obtained using the ruler method, LiDAR technique, and ImageJ analysis were 112.99 ± 110.07 cm2, 73.59 ± 72.97 cm2, and 74.29 ± 72.15 cm2, respectively. The Pearson correlation coefficient was higher for the LiDAR application (0.995) than for the conventional ruler methods (mean difference, -5.0000 cm2), as was the degree of agreement (mean difference, 38.6933 cm2). Wound size measurement using LiDAR is a simple and reliable method that will enable practitioners to conveniently assess wounds with a flattened and irregular shape with higher accuracy. However, non-flattened wounds cannot be assessed owing to the technical limitations of LiDAR.

Introduction of Deep Learning-Based Infrared Image Analysis to Marginal Reflex Distance1 Measurement Method to Simultaneously Capture Images and Compute Results: Clinical Validation Study.

Marginal reflex distance1 (MRD1) is a crucial clinical tool used to evaluate the position of the eyelid margin in relation to the cornea. Traditionally, this assessment has been conducted manually by plastic surgeons, ophthalmologists, or trained technicians. However, with the advancements in artificial intelligence (AI) technology, there is a growing interest in the development of automated systems capable of accurately measuring MRD1. In this context, we introduce novel MRD1 measurement methods based on deep learning algorithms that can simultaneously capture images and compute the results. This prospective observational study involved 154 eyes of 77 patients aged over 18 years who visited Chungnam National University Hospital between 1 January 2023 and 29 July 2023. We collected four different MRD1 datasets from patients using three distinct measurement methods, each tailored to the individual patient. The mean MRD1 values, measured through the manual method using a penlight, the deep learning method, ImageJ analysis from RGB eye images, and ImageJ analysis from IR eye images in 56 eyes of 28 patients, were 2.64 ± 1.04 mm, 2.85 ± 1.07 mm, 2.78 ± 1.08 mm, and 3.07 ± 0.95 mm, respectively. Notably, the strongest agreement was observed between MRD1_deep learning (DL) and MRD1_IR (0.822, p < 0.01). In a Bland-Altman plot, the smallest difference was observed between MRD1_DL and MRD1_IR ImageJ, with a mean difference of 0.0611 and ΔLOA (limits of agreement) of 2.5162, which was the smallest among all of the groups. In conclusion, this novel MRD1 measurement method, based on an IR camera and deep learning, demonstrates statistical significance and can be readily applied in clinical settings.