Central anterior chamber depth correlated with white-to-white distance in normal, long, and short eyes.

PURPOSE: To explore the associations between central anterior chamber depth (CACD) and other anterior segment biometric parameters and to determine the possible determinants of CACD in short, normal, and long eyes. METHODS: The biometric data of pre-operation patients aged 50-80 years with coexisting cataract and primary angle-closure disease or senile cataract were reviewed. Axial length (AL), CACD, lens thickness (LT), central corneal thickness (CCT), and white-to-white distance (WTW) were measured by Lenstar optical biometry (Lenstar 900). The data of 100 normal eyes (AL = 22 to 26 mm), 100 short eyes (AL ≤ 22 mm), and 100 long eyes (AL ≥ 26 mm) were consecutively collected for subsequent analyses. RESULTS: The mean age of the subjects was 66.60 ± 7.85 years, with 25.7% of the sample being men. Both CACD and WTW were found to be smallest in short eyes and were smaller in normal eyes than in long eyes (F = 126.524, P < 0.001; F = 28.458, P < 0.001). The mean LT was significantly thicker in short eyes than in normal and long eyes (4.66 mm versus 4.49 mm versus 4.40 mm; F = 18.099, P < 0.001). No significant differences were observed in CCT between the three AL groups (F = 2.135, P = 0.120). Stepwise regression analysis highlighted AL, LT, and WTW as three independent factors associated with CACD in the normal AL group. In the short AL group and long AL group, LT and WTW were independent factors associated with CACD. CONCLUSIONS: CACD increases as AL elongates and reaches a peak when AL exceeds 26 mm. Furthermore, CACD showed inverse correlation with LT and positive correlation with WTW. A relatively small WTW results in an anteriorly positioned lens, and thus, a decrease in CACD.

Quality assessment of non-mydriatic fundus photographs for glaucoma screening in primary healthcare centres: a real-world study.

BACKGROUND: This study assessed the quality distribution of non-mydriatic fundus photographs (NMFPs) in real-world glaucoma screening and analysed its influencing factors. METHODS: This cross-sectional study was conducted in primary healthcare centres in the Yinzhou District, China, from 17 March to 3 December 2021. The quality distribution of bilateral NMFPs was assessed by the Digital Reading Department of the Eye Hospital of Wenzhou Medical University. Generalised estimating equations and logistic regression models identified factors affecting image quality. RESULTS: A total of 17 232 photographs of 8616 subjects were assessed. Of these, 11.9% of images were reliable for the right eyes, while only 4.6% were reliable for the left eyes; 93.6% of images were readable in the right eyes, while 90.3% were readable in the left eyes. In adjusted models, older age was associated with decreased odds of image readability (adjusted OR (aOR)=1.07, 95% CI 1.06~1.08, p<0.001). A larger absolute value of spherical equivalent significantly decreased the odds of image readability (all p<0.001). Media opacity and worse visual acuity had a significantly lower likelihood of achieving readable NMFPs (aOR=1.52, 95% CI 1.31~1.75; aOR=1.70, 95% CI 1.42~2.02, respectively, all p<0.001). Astigmatism axes within 31°~60° and 121°~150° had lower odds of image readability (aOR=1.35, 95% CI 1.11~1.63, p<0.01) than astigmatism axes within 180°±30°. CONCLUSIONS: The image readability of NMFPs in large-scale glaucoma screening for individuals 50 years and older is comparable with relevant studies, but image reliability is unsatisfactory. Addressing the associated factors may be vital when implementing ophthalmological telemedicine in underserviced areas. TRIAL REGISTRATION NUMBER: ChiCTR2200059277.

Effect of low dose laser cycloplasty on deepening anterior chamber in chronic angle-closure glaucoma.

AIM: To describe the outcome of using low-dose laser cycloplasty (LCP) in chronic angle-closure glaucoma (CACG). METHODS: A retrospective case series. Medical charts of CACG patients who underwent LCP in the Eye Hospital of Wenzhou Medical University were reviewed. The main outcomes included intraocular pressure (IOP), the number of glaucoma medication, anterior segment parameters and surgery-related complications. RESULTS: A total of 7 eyes of 7 CACG patients (age 38.9±11.0y) underwent LCP with a mean follow-up of 27.1±13.7mo (range 16-48mo). Following LCP, mean IOP and glaucoma medications decreased from 26.1±6.1 mm Hg with 3.1±1.1 glaucoma medications pre-treatment to 14.9±3.1 mm Hg (P=0.027) with 0.4±1.1 glaucoma medications (P=0.001) at final follow-up. The anterior chamber depth (ACD), angle opening distance500 and trabecular-iris angle increased from 1.65±0.33 mm, 0.05 mm (range 0-0.30 mm) and 5.1° (range, 0-31.97°) at baseline to 1.98±0.43 mm (P=0.073), 0.53 mm (range 0.42-0.91 mm, P=0.015), 45.9° (range, 40.2°-59.4°, (P=0.015) in the long-term follow-up, respectively. The deepening of ACD and reopening of anterior chamber angle (ACA) was observed in 6 eyes (85.7%). CONCLUSION: LCP is a promising treatment option for patients with CACG via reducing IOP and glaucoma medication without serious complications. In addition, LCP can bring a significant deepening in ACD and reopening of ACA.

Incidence and characteristics of aqueous misdirection after glaucoma surgery in Chinese patients with primary angle-closure glaucoma.

BACKGROUND: To report the incidence and clinical characteristics of aqueous misdirection (AM) after glaucoma surgery in Chinese patients with primary angle-closure glaucoma. METHODS: Medical records of all patients diagnosed with primary angle-closure glaucoma who underwent glaucoma surgery in the Eye Hospital of Wenzhou Medical University between January 2012 and December 2021 were retrospectively reviewed. Cases of AM were identified through a keyword-based search. The incidence of AM was calculated. Demographic and clinical characteristics of the AM patients were also described. RESULTS: A total of 5044 eyes with primary angle-closure glaucoma were included (mean age 65.81 ± 9.96 years, 68.11% women). Thirty-eight eyes developed AM, presenting an overall incidence of 0.75%. The mean time interval between surgery and first record of AM diagnosis was 2.57 ± 5.24 months (range, 0 day to 24 months). The incidence of AM was significantly higher in patients aged ≤ 40 years (21.28%) and those aged 40-50 years (3.32%), compared to those > 50 years (0.42%) (P < 0.001). AM developed much more frequently among patients with chronic angle-closure glaucoma (1.30%), compared to those with acute angle-closure glaucoma (0.32%, P < 0.001). Eleven eyes (0.37%) developed AM following non-filtering surgery compared to 24 eyes (2.27%) after filtering surgery (P < 0.001). CONCLUSION: The incidence of AM after glaucoma surgery was 0.75% in Chinese patients with primary angle closure glaucoma. Younger age, chronic angle-closure glaucoma, and undergoing filtering surgery, were identified as associated risk factors for developing AM. Phacoemulsification may have less risk of developing AM compared to filtering surgery.

Refractive outcomes of scleral-sutured posterior chamber intraocular lenses in post-traumatic eyes.

PURPOSE: To evaluate the refractive outcomes of scleral-sutured IOL 2 mm posterior to the limbus in post-traumatic eyes using SRK/T formula. METHODS: This single-center retrospective case series included 35 eyes from 35 post-traumatic patients undergoing scleral-suture of ErgomaX IOLs by a single experienced surgeon. Preoperative predicted refraction, procedure-related complications, and postoperative spherical equivalent (SE) at least 1 month after surgery were recorded. The prediction error (PE) was calculated as the difference between the postoperative SE and preoperative predicted refraction. RESULTS: Of the 35 post-traumatic patients, 28 patients were aphakia without capsular support, and 7 patients were traumatic lens dislocation or subluxation. The mean age at surgery was 56.03 ± 14.56 years and 28 patients were men (80%). The mean postoperative spherical equivalent (SE) and postoperative astigmatism were - 1.23 ± 0.82 D and 1.57 ± 1.14 D, respectively. The mean prediction error (ME) of SRK/T formula was - 0.17 D. The mean absolute error (MAE) was 0.48D. The prediction accuracy was 60.0% for refractive errors of ± 0.50 D and 85.7% for refractive errors of ± 1.00D. Multiple linear regression analyses revealed that IOL power has positive correlation with PE. CONCLUSION: Assumption of in-the-bag IOL position when calculating IOL (52501TY, ErgomaX) power for standardizing scleral-sutured IOL 2 mm posterior to the limbus demonstrates acceptable refractive outcomes. The accuracy of IOL power calculation using the SRK/T formula for eyes needing low IOL power or high IOL power may be affected by the uncertain position of postoperative IOL and further studies are needed.

Enhanced Faraday effects of magneto-plasmonic crystals with plasmonic hexagonal hole arrays.

Magneto-optical (MO) properties of the bilayed Au/BIG and trilayered Au/BIG/Au magneto-plasmonic crystals (MPCs) were analyzed by the finite-difference time-domain method. In contrast to the low deflection angle and transmission of the smooth thin film, all the heterostructures with perforated holes in the top Au film displayed a similar trend with two strong resonant bands in Faraday rotation and transmittance in the near infrared wavelength range. The bands and electric distribution relative to the component and hole structure were revealed. The MPC with plasmonic hexagonal holes was found to own superior Faraday effects with distinctive anisotropy. The evolution of the resonant bands with the size and period of hexagonal holes, the thickness of different layers, and the incident light polarization was illustrated. The Faraday rotation of the optimized bilayed and trilayered hexagonal MPCs was improved 15.3 and 17.5 times, and the transmittance was enhanced 12.1 and 11.1 folds respectively at the resonant wavelength in comparison to the continuous Au/BIG film, indicating that the systems might find potential application in MO devices.

Enhancement of Room-Temperature Photoluminescence and Valley Polarization of Monolayer and Bilayer WS2 via Chiral Plasmonic Coupling.

Transition-metal dichalcogenides with intrinsic spin-valley degree of freedom have enabled great potentials for valleytronic and optoelectronic applications. However, the degree of valley polarization is usually low under nonresonant excitation at room temperature due to the phonon-assisted intervalley scattering. Here, achiral and chiral Au arrays are designed to enhance the optical response and valley polarization in monolayer and bilayer WS2. A considerable band edge emission with 7 times increment is realized under the resonant coupling with Au dimer-prism arrays. Valley polarization enhancement is quantitatively predicted by the inherent mechanisms from elevated electromagnetic field intensity and radiation efficiency and further realized in polarized photoluminescence. A tunable valley polarization up to 30.0% is achieved in bilayer WS2 under a nonresonant excitation at room temperature. All of these results provide a promising route toward the development of room-temperature valley-dependent optoelectronic devices.

Gradient Engineered Light Absorption Layer for Enhanced Carrier Separation Efficiency in Perovskite Solar Cells.

Carrier transport behavior in the perovskite light absorption layer significantly impacts the performance of perovskite solar cells (PSCs). In this work, reduced carrier recombination losses were achieved by the design of a band structure in perovskite materials. An ultrathin (PbI2/PbBr2)n film with a gradient thickness ratio was deposited as the lead halide precursor layer by a thermal evaporation method, and PSCs with a gradient band structure in the perovskite absorption layer were fabricated by a two-step method in ambient atmosphere. For comparison, PSCs with homogeneous perovskite materials of MAPbI3 and MAPbIxBr3 - x were fabricated as well. It is found that the gradient type-II band structure greatly reduces the carrier lifetime and enhances the carrier separation efficiency. As a result, the PSCs with a gradient band structure exhibit an average power conversion efficiency of 17.5%, which is 1-2% higher than that of traditional PSCs. This work provides a novel method for developing high-efficiency PSCs.

Improved Open-Circuit Voltage and Repeatability of Perovskite Cells Based on Double-Layer Lead Halide Precursors Fabricated by a Vapor-Assisted Method.

Highly repeatable fabrication of compact perovskite films is crucial for large-area perovskite cells (PSCs) in commercial applications. In this work, a vapor-assisted method with the combination of spin-coating and thermal evaporation is employed to fabricate the double-layer PbI2/PbIxBr(2-x) precursor. It is found that surface morphologies of perovskite films could be tailored through tuning the spin-coating speed (the first precursor layer) and chemical compositions (the second precursor layer). The continuous pinhole-free perovskite films are successfully fabricated by double-layer PbI2/PbBr2 precursors. The open-circuit voltages of all the corresponding cells exceed 1.00 V, showing an average value of 1.02 V. The high mean voltage and small variation reveals high repeatability of this method. This work provides a potential method to achieve large-area and high-efficiency PSCs.

Polarization-Controllable Plasmonic Enhancement on the Optical Response of Two-Dimensional GaSe Layers.

Resonant plasmonic coupling has been considered as a promising strategy to enhance the optical response and manipulate the polarization of two-dimensional (2D) layer materials toward the practical applications. Here, a hybrid structure with periodic Ag nanoprism arrays was designed and fabricated on 2D GaSe layers to enhance these optical properties. By using the optimized hybrid structure with well-matched resonance, significant enhanced Raman scattering and band edge emission were successfully realized, and it is also interestingly found that the higher enhancement would be achieved while decreasing the thickness of GaSe layers. Theoretical simulation indicated that the strongly enhanced local field and the modified charge densities are the main reasons. By further introducing the patterned gratings on the plasmonic hybrid structure, selective excitation with controllable polarization was readily realized, besides the strongly enhanced photoluminescence intensity. This work provides a strategy for the plasmonic engineering of polarization controllable 2D optoelectronic devices.

In-plane Anisotropy of Quantum Transport in Artificial Two-dimensional Au Lattices.

We report an experimental observation and direct control of quantum transport in artificial two-dimensional Au lattices. Combining the advanced techniques of low-temperature deposition and newly developed double-probe scanning tunneling spectroscopy, we display a two-dimensional carrier transport and demonstrate a strong in-plane transport modulation in the two-dimensional Au lattices. In well-ordered Au lattices, we observe the carrier transport behavior manifesting as a band-like feature with an energy gap. Furthermore, controlled structural modification performed by constructing coupled "stadiums" enables a transition of system dynamics in the lattices, which in turn establishes tunable resonant transport throughout a wide energy range. Our findings open the possibility of the construction and transport engineering of artificial lattices by the geometrical arrangement of scatterers and quantum chaotic dynamics.

Nonuniform Effect of Carrier Separation Efficiency and Light Absorption in Type-II Perovskite Nanowire Solar Cells.

Coaxial structures exhibit great potential for the application of high-efficiency solar cells due to the novel mechanism of radial charge separation. Here, we intensively investigate the nonuniform effect of carrier separation efficiency (CSE) and light absorption in perovskite-based type-II coaxial nanowire solar cells (ZnO/CH3NH3PbI3). Results show that the CSE rapidly decreases along the radial direction in the shell, and the value at the outer side becomes extremely low for the thick shell. Besides, the position of the main light absorption gradually moves to the outer side with the increase of the shell thickness. As a result, the external quantum efficiency shows a positional dependence with a maximal value close to the border of the nanowire. Eventually, in our case, it is found that the maximal power conversion efficiency of the solar cells reduces from 19.5 to 17.9% under the effect of the nonuniformity of CSE and light absorption. This work provides a basis for the design of high-efficiency solar cells, especially type-II nanowire solar cells.

Enhanced magneto-optical effects in composite coaxial nanowires embedded with Ag nanoparticles.

Nanostructures decorated with noble metal nanoparticles (NPs) exhibit potential for use in highly sensitive optoelectronic devices through the localized surface plasmon resonance (LSPR) effect. In this study, Faraday rotation was significantly enhanced through the structural optimization of ferromagnetic (FM)/semiconductor composite nanostructures. Experimental and theoretical results revealed that the position of noble metal NPs significantly influenced the coupling of the LSPR-enhanced electromagnetic field with FM materials. Furthermore, nanostructures embedded with noble metals demonstrated an improved capability to efficiently use the electromagnetic field compared to other structures. The Faraday rotation of ZnO/Ag(NPs)/Fe was enhanced 58 fold compared to that of the ZnO(film)/Fe. This work provides a basis for the design of nanoarchitectures for miniaturized high-performance magneto-optical devices.

Facile synthesis of composition-tuned ZnO/Zn x Cd1-x Se nanowires for photovoltaic applications.

ZnO/Zn x Cd1-x Se coaxial nanowires (NWs) have been successfully synthesized by combining chemical vapor deposition with a facile alternant physical deposition method. The shell composition x can be precisely tuned in the whole region (0 ≤ x ≤ 1) by adjusting growth time ratio of ZnSe to CdSe. As a result, the effective bandgaps of coaxial nanowires were conveniently modified from 1.85 eV to 2.58 eV, almost covering the entire visible spectrum. It was also found that annealing treatment was in favor of forming the mixed crystal and improving crystal quality. An optimal temperature of 350°C was obtained according to our experimental results. Additionally, time resolved photo-luminescence spectra revealed the longest carrier lifetime in ZnO/CdSe coaxial nanowires. As a result, the ZnO/CdSe nanowire cell acquired the maximal conversion efficiency of 2.01%. This work shall pave a way towards facile synthesis of ternary alloys for photovoltaic applications.