Flexible Lens Research Articles

An adaptive drug-releasing contact lens for personalized treatment of ocular infections and injuries

This research introduces an innovative solution to address the challenges of bacterial keratitis and alkali burns. Current treatments for bacterial keratitis and alkali burns rely on the frequent use of antibiotics and anti-inflammatory eye drops. However, these approaches suffer from poor bioavailability and fluctuating concentrations, leading to limited efficacy and potential drug resistance. Our approach presents an adaptive drug-releasing contact lens responsive to reactive oxygen species (ROS) at ocular inflammation sites, synchronously releasing Levofloxacin and Diclofenac. During storage, minimal drug release occurred, but over 7 days of wear, the lens maintained a continuous, customizable drug release rate based on disease severity. This contact lens had strong antibacterial activity and biofilm prevention, effectively treating bacterial keratitis. When combined with autologous serum, this hydrophilic, flexible lens aids corneal epithelial regeneration, reducing irritation and promoting healing. In summary, this ROS-responsive drug-releasing contact lens combines antibacterial and anti-inflammatory effects, offering a promising solution for bacterial keratitis and alkali burns.

A beam-steering antenna with low deflecting-loss enabled by a miniaturized flexible lens

A miniaturized flexible lens is proposed for beam control of broadband antenna with low deflection loss. Different from traditional approaches to phase modulation, the three-segment principle presented in this article significantly lowers the maximum necessary phase difference generated by modulated waves, thus reducing the height of the lens and antenna profile. The phase modulation performance of the lens is reconfigured by adjusting the layout of the phase modulation units PMUs according to distribution requirements. Then, a Vivaldi antenna utilizing the miniaturized lens is designed, fabricated, and tested to demonstrate the system’s beam deflecting characteristics. The experimental results demonstrate the capability of the antenna to cover a deflecting range wider than [−20°, 19°] with deflecting loss below 1.4 dB throughout the entire 8–10 GHz working band. Over the operating band, the deflecting gain is greater than 8.7 dBi.

Beyond Oral and Written Prophecy

Abstract This article examines performance as part of the prophetic and revelatory in ancient Jewish literature. The body of the article centres on the so-called “prophetic actions” within the biblical corpus. Scholarship’s use of this category has highlighted nonverbal performance as a part of prophecy but raises questions regarding the efficacy of these varied actions as well as their distinction from written or spoken prophecy. Here I reapply J.L. Austin’s speech act theory to further examine their function. Isaiah 20:1–6 and Jeremiah 51:59–64, my central case studies, demonstrate not only the variety among these performances but also how interwoven they are with prophetic biography, writing, and speech. Exploring such phenomena through this more flexible lens further illuminates the continued significance of performance and prophecy in the Second Temple period, which the article demonstrates using 11QPsalmsa and the Exagoge of Ezekiel.

Vitrectomy combined with lens capsule flap transplantation in the treatment of high myopia macular hole retinal detachment: study protocol for a prospective randomised controlled trial

IntroductionVitrectomy combined with internal limiting membrane (ILM) peeling, flap or tamponade is widely used in the treatment of macular diseases, such as macular hole (MH) and high myopia macular hole...

Numerical study of the effect of individual racks in lenses on the operation of nonlinear lenticular membrane-pneumatic systems by the step method

Objective. The purpose of this study is to substantiate the methodology for static calculation of light coatings for large-span structures with lenticular membrane-pneumatic lenses, including racks at individual points of the span, using the step-iterative method of parameter increments.Method. The study involves the phased application of the finite element method (FEM), the universal equation of state of gas and the improved Euler-Cauchy numerical procedure, taking into account the geometric nonlinearity of systems and the physical nonlinearity of the elastic work of air in lenses and taking into account the aftereffect of excess air pressure.Result. A comparison is made in terms of rigidity and load-bearing capacity of membrane-pneumatic lenses, reinforced with individual posts, with the corresponding flexible membrane-pneumatic lenses of the classical type.Conclusion. In the presence of racks, the effect of a significant increase in the rigidity and bearing capacity of lenticular membrane-pneumatic systems is observed for large spans. The distance between the posts along the building can be adjusted during the design and thereby regulate the effect of strengthening the system. The maximum deflections of the lenticular-shaped membrane-pneumatic system reinforced with struts are much less than the maximum deflections of the lenticular membrane-pneumatic system of the classical type under the action of the calculated snow load of the first and second limit states.

Staging Indigeneity: Salvage Tourism and the Performance of Native American History

Staging Indigeneity: Salvage Tourism and the Performance of Native American History

Two-dimensional biocompatible plasmonic contact lenses for color blindness correction

Color blindness, or color vision deficiency (CVD), is an ocular disease that suppresses the recognition of different colors. Recently, tinted glasses and lenses have been studied as hopeful devices for color blindness correction. In this study, 2D biocompatible and flexible plasmonic contact lenses were fabricated using polydimethylsiloxane (PDMS) and a low-cost, and simple design based on the soft nano-lithography method and investigated for correction of red–green (deuteranomaly) color blindness. In addition, the stability test of the fabricated plasmonic contact lenses was investigated into the phosphate buffered saline (PBS) solution and the proposed lens offers an excellent stability into the PBS solution. The plasmonic contact lens proposed herein is based on the plasmonic surface lattice resonance (SLR) phenomenon and offers a good color filter for color blindness correction. The biocompatibility, low cost, stability, and simple fabrication of these contact lenses can offer new insights for applications of color blindness correction.

Flexible Varifocal Lens with Aberration Correction Function

Flexible Varifocal Lens with Aberration Correction Function

Intra Ocular Lens Technology - A Review of Journey from Its Inception

Aim: To understand the advancement and development in Intraocular lens.
 Introduction: Now a day cataract surgery is the most commonly performed surgical procedure in the world. Removing the opaque, cataractous lens and replacing it with an artificial lens to achieve near to normal visual acuity post operatively is not only accepted but by and large a mandatory norm.
 Findings: The lenses used for the purpose are called Intra Ocular Lens. Ridley’s brilliance has improved the lives of many millions of people. The gradual improvement in IOL design, first in making flexible lenses, then the ever-improving optical outcomes have meant that vision after cataract surgery has never been better – in the developed world.
 Conclusion: We have come a long way in terms of IOL design, but many people with cataracts in rural areas of the developing world, need help to catch up.

Employing adhesion technology to bond natural rubber faceblank and polyurethane elastomer flexible lens for gasmask

ABSTRACT In this paper, the connection between natural rubber (NR) faceblank and polyurethane elastomer (PUE) flexible lens for gasmask employs adhesion technology instead of traditional clamp connection. Remarkable polar disparity between NR and PUE makes the adhesion unsatisfied. In order to improve bonding properties, the NR faceblank was surface modified by trichloroisocyanuric acid (TIC) prior to adhesion. Surface compositions and morphologies of the pristine and modified NR substrates were analyzed by X-ray photoelectron spectroscopy (XPS), attenuated total reflection fourier transform infrared spectroscopy (ATR-FTIR) and scanning electron microscopy (SEM), and the bonding properties of NR/PUE bonded joints were investigated. Results show that the adhesion technology can be effectively used in gasmask to secure PUE flexible lens to NR faceblank. Chemical modification of NR faceblank changes remarkably both chemical composition and roughness, and consequently improves the bonding performance. Modification plays an important role in the improvement of adhesion.

PHACOEMULSIFICATION OF BROWN CATARACTS ON AVITREAL EYES

Analysis of the features of surgical treatment of brown cataracts in the eyes with previously performed posterior vitrectomy. The study included 25 patients (25 eyes) with nuclear cataracts 6+ density according to LOCS III classification. All patients underwent microinvasive posterior vitrectomy more than 6 months ago. Microcoaxial (2.2 mm) phacoemulsification of cataract with implantation of flexible intraocular lens was planned for all patients. In 15 patients (60 %), a system of capsule hooks was used in order to support the capsule bag 4 in 16 % of cases and 6 in 44 % of cases. Results and discussion. Sutureless surgery were performed in 24 patients (96 %). In one case with nigra cataract despite the use of capsule hooks, due to the high risk of dislocation of the lens into the vitreous cavity, the surgery was converted into a large incision. Microcoaxial phacoemulsification is the surgery of choice in the case of a combination of dense lens and lack of vitreous support. The use of capsular hooks greatly simplifies surgery and increases the chances of sutureless surgery.

A fast processing route of aspheric polydimethylsiloxane lenses array (APLA) and optical characterization for smartphone microscopy

A fast processing route of aspheric polydimethylsiloxane (PDMS) lenses array (APLA) is proposed via the combined effect of inverted gravitational and heat-assisted forces. The fabrication time can be dramatically reduced to ~30s, compared favorably to the traditional duration of ~2 hours of repeated cycles of addition-curing processes. In this paper, a low-cost flexible lens can be fabricated by repeatedly depositing, inverting, curing a hanging transparent PDMS elastomer droplet on a previously deposited curved structure. Complex structures with aspheric curve features and various focal lengths can be successfully produced and the fabricated 4 types of APLA have various focal lengths in the range of 7.03mm, 6.00mm, 5.33mm, and 4.43mm, respectively. Empirically, a direct relationship between the PDMS volume and focal lengths of the lenses can be experimentally deducted. Using these fabricated APLA, an ordinary commercial smartphone camera can be easily transformed to a low-cost, portable digital microscopy (50×magnification) such that point of care diagnostic can be implemented pervasively.

An investigation of the effect of silicone oil on polymer intraocular lenses by means of PALS, FT-IR and Raman spectroscopies

The effect of the polydimethylsiloxane (PDMS) based silicone oil, that is widely used in vitreoretinal surgery, on internal structures of the polymer intraocular lenses was investigated. The effect of PDMS was studied on the polymethyl methacrylate (PMMA) rigid lenses and poly(2-hydroxyethyl methacrylate) (PHEMA) flexible lenses. The research was carried out by means of the positron lifetime spectroscopy (PALS) as well as the infrared spectroscopy (FT-IR) and the Raman spectroscopy (RS). The studies involving the use of PALS and FT-IR methods have revealed that the PHEMA based lenses absorbed, whereas the PMMA lenses did not absorb, silicone oil. The results obtained with the use of the RS method were inconclusive, probably due to the too low intensity of the characteristic PDMS bands. The evidence from this study was discussed in terms of physics and related to the clinical use of both silicone oil and intraocular lenses.

Ultrafast Spectroscopy Based on Temporal Focusing and Its Applications

The whole family of the parametric spectro-temporal analyzer (PASTA) system has enriched the capability of our tool box in ultrafast spectrum measurements. The advent of the dispersive stretching technology started the era of the temporal spectrum analyzer, and it is easy to implement with stable results, while only capable of short pulses at low-repetition-rate. To enlarge the temporal observation window, a time-lens is first incorporated in the single-lens PATSA system. It can characterize stationary sources as well as some nonperiodic waveforms. To further enhance the observation flexibility, a pair of time-lens structure is introduced to perform the telescope/wide-angle PASTA. Leveraging the merit of instantaneous response, as well as the flexible lens structure; here, we present a 100-MHz frame rate PASTA system, with 17 times zoom in/out ratio for different observation ranges. Each configuration has its optimum application range. As a proof of concept and also for the first time, we demonstrate some of its bio-imaging applications, including the time-stretch microscopy and the tomography systems.

Aging Dogs Manifest Myopia as Measured by Autorefractor.

ObjectiveDogs, like humans, experience eye changes with aging: hardening and clouding of the lens and accumulated oxidative damage from UV sunlight. It has been debated whether such changes could be affecting the visual function of dogs. The objective of this study was to determine if autorefractometry could be used to measure visual function in dogs.Animals and MethodsNine Beagle dogs (ages 1 to 14 years) were examined by a veterinary ophthalmologist and their eyes determined to be free of cataracts. Spherical equivalent refractive error was measured by handheld autorefractor (Welch Allyn SureSight) under both indirect and direct lighting conditions with five measurements per condition, per eye. Measures were repeated on three different days for each dog within six weeks. Nonparametric statistics were used to detect differences among lighting conditions and test days, and between eyes. Spearmen correlation assessed the visual measurement outcomes’ association with age.ResultsThere was no difference for day-to-day or between-eye measurements. Significantly, the Beagles showed a myopic shift with aging (average spherical equivalent ranged from plano to -3.00 diopters), suggesting that dogs become more near-sighted as they age (r = -0.48 and -0.73 under direct and indirect lights; p<0.05 both). Younger dogs were able to make larger accommodation changes from indirect light to direct light conditions, indicating a more flexible lens (r = -0.50, p<0.05).ConclusionsAlthough designed for humans, the hand-held autorefractor technique is applicable to dogs and sensitive to light conditions. The age-associated myopic shift could be expected to compromise dogs’ visual functions.

Mechanically tunable aspheric lenses via additive manufacture of hanging elastomeric droplets for microscopic applications

Mechanically deformable lenses with dynamically tunable focal lengths have been developed in this work. The fabricated five types of aspheric polydimethylsiloxane (PDMS) lenses presented here have an initial focal length of 7.0, 7.8, 9.0, 10.0 and 10.2 mm. Incorporating two modes of operation in biconvex and concave–convex configurations, the focal lengths can be tuned dynamically as 5.2–10.2, 5.5–9.9, 6.6–11.9, 6.1–13.5 and 6.6–13.5 mm respectively. Additive manufacturing was utilized to fabricate these five types of aspheric lenses (APLs) via sequential layering of PDMS materials. Complex structures with three-dimensional features and shorter focal lengths can be successfully produced by repeatedly depositing, inverting and curing controlled PDMS volume onto previously cured PDMS droplets. From our experiments, we empirically found a direct dependence of the focal length of the lenses with the amount (volume) of deposited PDMS droplets. This new mouldless, low-cost, and flexible lens fabrication method is able to transform an ordinary commercial smartphone camera into a low-cost portable microscope. A few microscopic features can be readily visualized, such as wrinkles of ladybird pupa and printed circuit board. The fabrication technique by successively applying hanging droplet and facile mechanical focal-length-tuning set-up can be easily adopted in the development of high-performance optical lenses.

Analysis of deformation of flexible hemispherical lens arrays based on soft elastomers.

In this paper, flexible hemispherical lens arrays based on soft elastomers were fabricated. Then, the effects of various geometric parameters on the deformation (i.e., hemispherical deformation and radial extension) of these lens arrays were investigated experimentally and were verified by finite element analysis. We focused on determining the relationship between the geometric parameters and the radius of curvature of the lens. We found that the height of the lens support post plays an important role in minimizing changes in the radius of curvature of the lens. The results of this research offer valuable design principles for flexible lens arrays, which can be used as an optical component of various flexible optoelectronic devices.

柔性变焦透镜发展现状

柔性变焦透镜发展现状

Double-Layer Metallic Holes Lens Based on Continuous Modulation of Phase and Amplitude

We have demonstrated numerically a lens design based on continuous modulation of both phase and amplitude utilizing array of double-layer metallic aluminum holes filled with silicon dioxide. The tuning range is 0-π and 0-0.3 for phase and amplitude, respectively, at wavelength 365 nm, allowing flexible lens design. Two lenses are designed and compared. At wavelength 365 nm, the lens based on pure phase modulation generates a 600-nm hot spot at a distance of 6.5 μm, while the phase-amplitude-modulation-based lens leads to an improved focusing spot size of 450 nm, which is beyond the diffraction limit 608 nm and the superoscillation criterion 462 nm. An example of subwavelength superoscillation focusing (0.32λ) is also demonstrated with a continuous amplitude modulated lens, which shows small sidelobe and broad view field. Our approach shows great potential in superoscillation lens design and can be applied to other optical spectrum ranges as well.

Ultrafast and versatile spectroscopy by temporal Fourier transform

One of the most remarkable and useful properties of a spatially converging lens system is its inherent ability to perform the Fourier transform; the same applies for the time-lens system. At the back focal plane of the time-lens, the spectral information can be instantaneously obtained in the time axis. By implementing temporal Fourier transform for spectroscopy applications, this time-lens-based architecture can provide orders of magnitude improvement over the state-of-art spatial-dispersion-based spectroscopy in terms of the frame rate. On the other hand, in addition to the single-lens structure, the multi-lens structures (e.g. telescope or wide-angle scope) will provide very versatile operating conditions. Leveraging the merit of instantaneous response, as well as the flexible lens structure, here we present a 100-MHz frame rate spectroscopy system – the parametric spectro-temporal analyzer (PASTA), which achieves 17 times zoom in/out ratio for different observation ranges.