Long-distance pattern projection through an unfixed multimode fiber with natural evolution strategy-based wavefront shaping.

Focusing light into an arbitrary pattern through complex media is desired in energy delivery-related scenarios and has been demonstrated feasible with the assistance of wavefront shaping. However, it still encounters challenges in terms of pattern fidelity and focusing contrast, especially in a noisy and perturbed environment. In this work, we show that the strategy relying on natural gradient ascent-based parameter optimization can help to resist noise and disturbance, enabling rapid wavefront optimization towards high-quality pattern projection through complex media. It is revealed that faster convergence and better robustness can be achieved compared with existing phase control algorithms. Meanwhile, a new fitness function based on cosine similarity is adopted for the algorithm, leading to higher focusing contrast without sacrificing similarity to the target pattern. As a result, long-distance projection of an arbitrary pattern can be accomplished with considerably enhanced performance through a 15-meter multimode fiber that is not fixed and susceptible to perturbation. With further engineering, the approach may find special interests for many biomedical applications, such as deep-tissue photon therapy and optogenetics, where free-space localized optical delivery encounters challenges.

Wavefront shaping: A versatile tool to conquer multiple scattering in multidisciplinary fields.

Optical techniques offer a wide variety of applications as light-matter interactions provide extremely sensitive mechanisms to probe or treat target media. Most of these implementations rely on the usage of ballistic or quasi-ballistic photons to achieve high spatial resolution. However, the inherent scattering nature of light in biological tissues or tissue-like scattering media constitutes a critical obstacle that has restricted the penetration depth of non-scattered photons and hence limited the implementation of most optical techniques for wider applications. In addition, the components of an optical system are usually designed and manufactured for a fixed function or performance. Recent advances in wavefront shaping have demonstrated that scattering- or component-induced phase distortions can be compensated by optimizing the wavefront of the input light pattern through iteration or by conjugating the transmission matrix of the scattering medium. This offers unprecedented opportunities in many applications to achieve controllable optical delivery or detection at depths or dynamically configurable functionalities by using scattering media to substitute conventional optical components. In this article, the recent progress of wavefront shaping in multidisciplinary fields is reviewed, from optical focusing and imaging with scattering media, functionalized devices, modulation of mode coupling, and nonlinearity in multimode fiber to multimode fiber-based applications. Apart from insights into the underlying principles and recent advances in wavefront shaping implementations, practical limitations and roadmap for future development are discussed in depth. Looking back and looking forward, it is believed that wavefront shaping holds a bright future that will open new avenues for noninvasive or minimally invasive optical interactions and arbitrary control inside deep tissues. The high degree of freedom with multiple scattering will also provide unprecedented opportunities to develop novel optical devices based on a single scattering medium (generic or customized) that can outperform traditional optical components.

Speckle-Based Optical Cryptosystem and its Application for Human Face Recognition via Deep Learning.

Face recognition has become ubiquitous for authentication or security purposes. Meanwhile, there are increasing concerns about the privacy of face images, which are sensitive biometric data and should be protected. Software-based cryptosystems are widely adopted to encrypt face images, but the security level is limited by insufficient digital secret key length or computing power. Hardware-based optical cryptosystems can generate enormously longer secret keys and enable encryption at light speed, but most reported optical methods, such as double random phase encryption, are less compatible with other systems due to system complexity. In this study, a plain yet highly efficient speckle-based optical cryptosystem is proposed and implemented. A scattering ground glass is exploited to generate physical secret keys of 17.2 gigabit length and encrypt face images via seemingly random optical speckles at light speed. Face images can then be decrypted from random speckles by a well-trained decryption neural network, such that face recognition can be realized with up to 98% accuracy. Furthermore, attack analyses are carried out to show the cryptosystem's security. Due to its high security, fast speed, and low cost, the speckle-based optical cryptosystem is suitable for practical applications and can inspire other high-security cryptosystems.

High-resolution photoacoustic microscopy with deep penetration through learning.

Optical-resolution photoacoustic microscopy (OR-PAM) enjoys superior spatial resolution and has received intense attention in recent years. The application, however, has been limited to shallow depths because of strong scattering of light in biological tissues. In this work, we propose to achieve deep-penetrating OR-PAM performance by using deep learning enabled image transformation on blurry living mouse vascular images that were acquired with an acoustic-resolution photoacoustic microscopy (AR-PAM) setup. A generative adversarial network (GAN) was trained in this study and improved the imaging lateral resolution of AR-PAM from 54.0 µm to 5.1 µm, comparable to that of a typical OR-PAM (4.7 µm). The feasibility of the network was evaluated with living mouse ear data, producing superior microvasculature images that outperforms blind deconvolution. The generalization of the network was validated with in vivo mouse brain data. Moreover, it was shown experimentally that the deep-learning method can retain high resolution at tissue depths beyond one optical transport mean free path. Whilst it can be further improved, the proposed method provides new horizons to expand the scope of OR-PAM towards deep-tissue imaging and wide applications in biomedicine.

Urothelial Dysfunction and Chronic Inflammation are Associated With Increased Bladder Sensation in Patients With Chronic Renal Insufficiency.

PURPOSE: Chronic kidney disease (CKD) or end-stage renal disease (ESRD) patients usually have lower urinary tract symptoms, such as frequency and urgency. Additionally, they frequently suffer from urinary tract infections. This study investigated dysfunction and chronic inflammation of the bladder urothelium in ESRD/CKD patients. METHODS: This study enrolled 27 patients with CKD (n=13) or ESRD (n=14) for urodynamic studies and bladder biopsies. Patients presented with detrusor underactivity (DU; n=8) or bladder oversensitivity (BO; n=19). Bladder biopsies were performed in these patients and in 20 controls. The bladder mucosa was examined for E-cadherin and zonula occludens-1 (ZO-1) expression, activated mast cell count (through tryptase staining), and urothelial apoptosis (through terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick-end labeling [TUNEL]). The urodynamic parameters were also compared with variables regarding urothelial dysfunction. RESULTS: The bladder mucosa samples of ESRD and CKD patients revealed significantly higher mast cell counts, more urothelial apoptosis, and lower levels of ZO-1 expression than the control samples. E-cadherin expression was significantly reduced in ESRD/CKD patients with DU, but not in ESRD/CKD patients with BO. Increased mast cell and apoptotic cell counts were also associated with ESRD/CKD with BO. Less expression of ZO-1 and E-cadherin was significantly associated with increased bladder sensation and a small bladder capacity. CONCLUSIONS: Bladder urothelial dysfunction and chronic inflammation were present to a noteworthy extent in patients with ESRD or CKD. Increased inflammation and defective barrier function were more notable in ESRD/CKD bladders with BO than in those with DU. The clinical characteristics of these patients may involve urothelial pathophysiology.

Topical ranibizumab as a treatment of corneal neovascularization.

PURPOSE: To examine the effect of topical ranibizumab on clinically stable corneal neovascularization (NV). METHODS: This was a prospective, open-label, monocentric, uncontrolled noncomparative study. Ten eyes of 9 patients with corneal NV received topical ranibizumab (1%) 4 times a day for 3 weeks with a follow-up period of 16 weeks. The main corneal NV outcome measures were: neovascular area, the area occupied by the corneal neovessels; vessel caliber (VC), the mean diameter of the corneal neovessels; and invasion area (IA), the fraction of the total cornea area covered by the vessels. This study was conducted at the Massachusetts Eye and Ear Infirmary, Boston, MA. RESULTS: Statistically significant decreases in neovascular area (55.3%, P < 0.001), which lasted through 16 weeks, and VC (59%, P < 0.001), which continued to improve up to week 16, were observed after treatment. No significant decrease was observed in IA (12.3%, P = 0.49). There was no statistically significant change in visual acuity or intraocular pressure. No adverse events ascribed to the treatment were noted. CONCLUSIONS: Topical application of ranibizumab is effective in reducing the severity of corneal NV in the context of established corneal NV, mostly through decrease in VC rather than IA.

Gamma-irradiation reduces the allogenicity of donor corneas.

PURPOSE: To evaluate the utility and allogenicity of gamma-irradiated corneal allografts. METHODS: Corneal buttons were harvested from C57BL/6 mice and decellularized with gamma irradiation. Cell viability was assessed using TUNEL and viability/cytotoxicity assays. Orthotopic penetrating keratoplasty was performed using irradiated or nonirradiated (freshly excised) C57BL/6 donor grafts and BALB/c or C57BL/6 recipients. Graft opacity was assessed over an 8-week period and graft survival was evaluated using Kaplan-Meier survival curves. Mixed-lymphocyte reactions and delayed-type hypersensitivity assays were performed to evaluate T-cell alloreactivity. Real-time PCR was used to investigate the corneal expression of potentially pathogenic T-helper 1, 2, and 17 cell-associated cytokines. RESULTS: Corneal cells were devitalized by gamma irradiation as evidenced by widespread cellular apoptosis and plasma membrane disruption. Nonirradiated allograft and isograft rates of survival were superior to irradiated allograft and isograft rates of survival (P < 0.001). Mixed lymphocyte reactions demonstrated that T-cells from irradiated allograft recipients did not exhibit a secondary alloimmune response (P < 0.001). Delayed-type hypersensitivity assays demonstrated that irradiated allografts did not elicit an alloreactive delayed-type hypersensitivity response in graft recipients (P ≤ 0.01). The corneal expression of T-helper 1, 2, and 17 cell-associated cytokines was significantly lower in failed irradiated allografts than rejected nonirradiated allografts (P ≤ 0.001). CONCLUSIONS: Gamma-irradiated corneas failed to remain optically clear following murine penetrating keratoplasty; however, gamma irradiation reduced the allogenicity of these corneas, potentially supporting their use in procedures such as anterior lamellar keratoplasty or keratoprosthesis implantation.

Short-term topical bevacizumab in the treatment of stable corneal neovascularization.

PURPOSE: To evaluate the safety and efficacy of topical bevacizumab in the treatment of corneal neovascularization. DESIGN: Prospective, nonrandomized, interventional case series. METHODS: setting: Institutional, multicenter clinical trial. study population: Twenty eyes from 20 patients with stable corneal neovascularization. intervention procedures: Patients were treated with topical 1.0% bevacizumab for 3 weeks and were monitored for a total of 24 weeks. main outcome measures: Primary outcome measures included: neovascular area, defined as the area of the corneal vessels themselves; vessel caliber, defined as the mean corneal vessel diameter; and invasion area, defined as the fraction of the total cornea into which the vessels extended. The occurrence of ocular and systemic adverse events was monitored closely. RESULTS: As compared with the baseline visit, patients exhibited a statistically significant improvement in neovascular area by week 6 (P = .007) and in vessel caliber by week 12 (P = .006). At the final visit, neovascular area, vessel caliber, and invasion area were reduced by 47.5%, 36.2%, and 20%, respectively. The decreases in neovascular area and vessel caliber were statistically significant (P < .001 and P = .003, respectively); however, the reduction in invasion area did not reach statistical significance (P = .06). There were no significant changes in the secondary outcomes, and there were no adverse events. CONCLUSIONS: Short-term topical bevacizumab treatment reduced the extent of stable corneal neovascularization as measured by neovascular area and vessel caliber with no associated adverse events. Interestingly, the degree of treatment efficacy was inversely proportional to the baseline invasion area.

Corneal neovascularization and the utility of topical VEGF inhibition: ranibizumab (Lucentis) vs bevacizumab (Avastin).

Corneal avascularity is necessary for the preservation of optimal vision. The cornea maintains a dynamic balance between pro- and antiangiogenic factors that allows it to remain avascular under normal homeostatic conditions; however, corneal avascularity can be compromised by pathologic conditions that negate the cornea's "angiogenic privilege." The clinical relevance of corneal neovascularization has long been recognized, but management of this condition has been hindered by a lack of safe and effective therapeutic modalities. Herein, the etiology, epidemiology, pathogenesis, and treatment of corneal neovascularization are reviewed. Additionally, the authors' recent findings regarding the clinical utility of topical ranibizumab (Lucentis®) and bevacizumab (Avastin®) in the treatment of corneal neovascularization are summarized. These findings clearly indicate that ranibizumab and bevacizumab are safe and effective treatments for corneal neovascularization when appropriate precautions are observed. Although direct comparisons are not conclusive, the results suggest that ranibizumab may be modestly superior to bevacizumab in terms of both onset of action and degree of efficacy. In order to justify the increased cost of ranibizumab, it will be necessary to demonstrate meaningful treatment superiority in a prospective, randomized, head-to-head comparison study.