Axial Length Research Articles

A First-Passage Model of Intravitreal Drug Delivery and Residence Time-Influence of Ocular Geometry, Individual Variability, and Injection Location.

Standard of care for various retinal diseases involves recurrent intravitreal injections. This motivates mathematical modeling efforts to identify influential factors for ocular drug residence time, aiming to minimize administration frequency. We sought to describe the vitreal diffusion of therapeutics in nonclinical species frequently used during drug development assessments. In human eyes, we investigated the impact of variability in vitreous cavity size and eccentricity, and in injection location, on drug disposition. Using a first-passage time approach, we modeled the transport-controlled distribution of two standard therapeutic protein formats (Fab and IgG) and elimination through anterior and posterior pathways. Anatomical three-dimensional geometries of mouse, rat, rabbit, cynomolgus monkey, and human eyes were constructed using ocular images and biometry datasets. A scaling relationship was derived for comparison with experimental ocular half-lives. Model simulations revealed a dependence of residence time on ocular size and injection location. Delivery to the posterior vitreous resulted in increased vitreal half-life and retinal permeation. Interindividual variability in human eyes had a significant influence on residence time (half-life range of 5-7days), showing a strong correlation to axial length and vitreal volume. Anterior exit was the predominant route of drug elimination. Contribution of the posterior pathway displayed a 3% difference between protein formats but varied between species (10%-30%). The modeling results suggest that experimental variability in ocular half-life is partially attributed to anatomical differences and injection site location. Simulations further suggest a potential role of the posterior pathway permeability in determining species differences in ocular pharmacokinetics.

Variability in Optic Nerve Head Morphology in High Axial Myopia and Its Association with Glaucoma

Purpose: To investigate optic disc morphology in high axial myopia and its associations with the deep-layer structure of the optic disc using optical coherence tomography and glaucoma.Methods: We retrospectively reviewed the medical records of 69 eyes (33 normal and 36 glaucomatous eyes) with an axial length of 26-27 mm. The eyes were categorized into two groups based on the optic disc tilt ratio (≥ 1.3 or < 1.3). Characteristics of optic disc morphology, including lamina cribrosa depth, peripapillary atrophy width, and Bruch’s membrane opening area, were compared between the two groups. Furthermore, factors related to mean deviation and global retinal nerve fiber layer (RNFL) thickness were analyzed.Results: The mean optic disc tilt ratio was 1.31 ± 0.23. Eyes with a tilt ratio ≥ 1.3 (30 eyes) had a higher likelihood of glaucoma (<i>p</i> = 0.035) and severe visual field (VF) defects (<i>p</i> < 0.001), a thinner global RNFL thickness (<i>p</i> = 0.046), and larger gamma peripapillary atrophy width (<i>p</i> < 0.001) compared to eyes with a tilt ratio < 1.3 (39 eyes). Linear regression analysis revealed that the optic disc tilt ratio was significantly associated with VF loss (<i>p</i> = 0.018) but not with global RNFL thinning (<i>p</i> = 0.203).Conclusions: Variations in optic disc morphology are observed in eyes with similar axial lengths, and a higher optic disc tilt ratio is associated with more severe VF defects. These findings suggest the potential influence of optic disc morphological changes due to axial elongation on the severity of glaucomatous damage.

Accuracy of intraoperative aberrometry versus preoperative biometry for intraocular lens power selection in short and long eyes.

To compare the accuracy of intraoperative wavefront aberrometry using the ORA VLynk system with different biometry-based formulas in short and long eyes after cataract surgery. This prospective study considered 48 eyes with axial lengths of <22.1 mm and 48 eyes with axial lengths of >25.0 mm. All eyes were implanted with the monofocal AcrySof IQ IOL, the power being determined using the ORA VLynk. The postoperative spherical equivalent (SE) at 3 months was compared to that predicted preoperatively using the SRK/T, Hoffer Q, Haigis, Holladay 2, Barrett Universal II, and Barrett True K formulas and intraoperatively using the ORA VLynk. Mean numerical and absolute errors and the percentage of eyes within ±0.50 D/1.00 D of their target were obtained. For long eyes, the mean absolute error values were 0.35, 0.52, 0.34, 0.30, 0.29, 0.27, and 0.24D for SRK/T, Hoffer Q, Haigis, Holladay 2, Barrett Universal II, Barrett True K, and ORA VLynk, respectively (p < 0.001). These values were 0.55, 0.45, 0.49, 0.40, 0.44, 0.44 and 0.50 D for short eyes, respectively (p < 0.001). The proportions of long eyes within ±0.50 D of the target were 77.08, 50, 75, 85.42, 83.33, 79.17, and 87.50%, respectively; and 50, 66.67, 60.42, 66.67, 60.42, 60.42, and 58.33%, respectively, for short eyes. The ORA VLynk performs better than all biometry-based formulas in long eyes and, in short eyes, it is as effective as SRK/T, Haigis, Barrett Universal II, and Barrett true K, with the Hoffer Q and Holladay 2 being the most accurate; however, the differences between the calculation methods were small. Identifier DRKS000028106.

Clinical characteristics of disc hemorrhages depending on their locations and glaucoma progression in myopic patients

This study aimed to investigate clinical characteristics and glaucoma progression in eyes with disc hemorrhage (DH) in the region of peripapillary atrophy (PPA) or DH in temporal region among glaucoma patients with myopia. One hundred ninety-six eyes of 196 glaucoma patients with myopia who were observed at least 4 years and had more than six visual field (VF) tests were included. Eyes with DHs located in the optic disc region at the superotemporal or inferotemporal locations were defined as typical DH. PPA area, disc ovality ratio, and disc torsion were measured. Length of γ-zone PPA, distance from disc edge to fovea, angle of scleral bending were measured using optical coherence tomography. Comparison of baseline characteristics between eyes with and without DH in PPA/DH in temporal region showed similar axial length (26.95 ± 1.60 mm; 26.82 ± 1.07 mm). γ-zone PPA was longer and angle of scleral bending was larger in eyes with DH in PPA/DH in temporal region (both p ≤ 0.001). Longer γ-zone PPA (β = 1.001; p = 0.018) and larger angle of scleral bending (β = 1.033; p = 0.008) were associated with presence of DH in PPA/DH in temporal region using logistic regression analysis. Eyes with DH in PPA/DH in temporal region had a smaller mean deviation slope of VF, a larger disc ovality ratio, a longer γ-zone PPA, and a larger PPA area when compared to those of eyes typical DH. VF progression was associated with absence of DH in PPA/DH in temporal region (p = 0.030) and larger angle of scleral bending (p = 0.019) using Cox proportional hazards model. DH in PPA/DH in temporal region was associated with stretching and deformation of sclera that may be result from myopic changes. Associated factors with VF progression was the degree of scleral deformation, not the presence of DH in PPA/DH in temporal region, showing that DH related to scleral deformation may possess clinical significance in glaucoma with myopia.

Relationship between Choroidal Thickness and Anterior Scleral Thickness in Patients with Keratoconus.

To evaluate the relationship between choroidal thickness (CT) and anterior scleral thickness (AST) in patients with subclinical keratoconus (SKC) and established keratoconus (KC). This single-center prospective case-control study included 97 eyes of 97 patients: 44 KC eyes, 14 SKC eyes, and 39 age- and axial length (AL)-matched healthy eyes. Using swept-source optical coherence tomography, the AST was manually measured in four directions and the CT was obtained automatically from the Early Treatment Diabetic Retinopathy Study (ETDRS) grid. Principal component analysis (PCA) was used to linearly reduce the dimensionality of nine CT inputs to one significant component, CT1. A multivariate model was created to evaluate the association between CT1, AST, and several ocular parameters in SKC and KC patients. Partial correlation was then performed to adjust the confounding factors and to examine the effect of AST on CT1. The PCA showed that CT1 accounts for 86.54% of the total variance in the nine original CTs of the ETDRS grid. The CT1 model was associated with age, AL, and AST in the superior meridian in SKC eyes, whereas in KC eyes, it was correlated with gender, age, AL, and AST in the inferior meridian (p < 0.001). The partial correlation between CT1 and AST in the superior zone was found to be significant, positive, and strong in SKC eyes (r = 0.79, p = 0.019), whereas a significant, positive, and moderate correlation between CT1 and AST at the inferior zone (r = 0.41, p = 0.017) was observed in KC eyes. Choroidal tissue was significantly correlated with the anterior sclera across the vertical meridian. This relationship was observed over the superior sclera in SKC eyes, whereas in established KC, it was over the inferior sclera. These results reveal new insights regarding the interactions between the anterior and posterior structures of the KC eyes and confirm the enigma of the pathophysiology of KC.

Comparison of ocular biometric measurements and intraocular lens power calculation using different methods in eyes with implantable collamer lenses

This prospective cohort study included 80 healthy candidates for Implantable Collamer Lens (ICL) implantation who underwent biometric assessments with Scheimpflug imaging (the Pentacam-AXL) and swept-source optical coherence tomography (SS-OCT; the IOLMaster-700), both before and 3 months after surgery. The main outcome measures were mean keratometry, anterior chamber depth, axial length, and various intraocular lens (IOL) calculation formulas (Haigis, SRK/T, Hoffer Q, Holladay 1, Barrett Universal 2, and Olsen). The interchangeability of the devices was assessed by generating 95% limits of agreement (95% LoA) and associated Bland-Altman plots. The average age of the participants was 31.5 ± 5.4 years (22–43), with 58 (72.5%) being female. Among the cases analyzed, 11 (13.4%) had incorrect anterior lens surface segmentation using the IOLMaster-700, and 1 case (1.2%) had inappropriate segmentation using the Pentacam-AXL. Postoperative IOL power calculation resulted in readings that were, on average, 0.15 to 0.30 D higher compared to preoperative measurements. The 95% LoAs could differ by up to 0.85 D higher after surgery, indicating weak agreement between pre- and postoperative measurements. There was poor agreement between the IOLMaster-700 and Pentacam-AXL in IOL power calculation for eyes with post-ICL implantation, with a difference of more than 1 D in the 95% LoAs. In conclusion, Scheimpflug imaging was found to be less susceptible than the SS-OCT technique to segmentation errors of the anterior lens surface after ICL implantation. Neither device showed interchangeable results for pre- versus postoperative IOL power calculation. The determination of IOL power by the IOLMaster-700 versus Pentacam-AXL was not interchangeable in eyes with ICL implantation.

One-year results of trabeculectomy with emphasis on the effect of patients' age.

This study investigated the association between one-year surgical outcomes following trabeculectomy and age, accounting for confounding factors. Retrospective observational study. Analyzing data from 305 patients undergoing initial trabeculectomy from 2019 onward, we employed three approaches to adjust variables: stratified analysis, regression analysis, and propensity score matching. Surgical success at 1-year post-surgery was defined by two criteria: achieving intraocular pressure of between 5 and 15 mmHg with a ≥ 20% reduction compared to pre-surgery levels and no additional glaucoma surgery (Criterion A); achieving intraocular pressure of between 5 and 12 mmHg with a ≥ 30% reduction compared to pre-surgery levels and no additional glaucoma surgery (Criterion B). Stratified analysis by age unveiled a significant increase in exfoliation glaucoma (XFG) and a trend towards shorter axial lengths with advancing age (both p < 0.0001). Older age groups were more likely to experience surgical failure in both Criterion A and B (p = 0.21, < 0.01). Univariate analysis showed age as a significant factor in surgical failure for Criterion A (p < 0.05) and a nearly significant factor for Criterion B (p = 0.12). However, this trend was not evident in multivariate analysis (p = 0.23/0.88), where XFG became a significant factor for surgical failure (both p < 0.001) in Criteria A and B. Propensity score matching revealed no significant differences in surgical success rates for Criteria A and B between younger and older patients (p = 1.00 and 0.88). Age is not a primary determinant of failure in trabeculectomy; however, the increasing incidence of XFG with aging suggests a potential for poorer outcomes.

Study on Crashworthiness of Shrink Tube Anti-Creep Device

Based on the requirements of the narrow installation space of a train end, compact energy-absorbing travel, and huge energy suck, a shrink tube anti-creep device was designed. The crashworthiness of different structures was studied by means of a material test, a trolley test, and numerical simulation. For every 1 mm increase in tube wall thickness, 1 mm increase in the axial length of the friction cone, and 0.01 increase in the friction coefficient, the mean crushing force (MCF) increased by 45.1 kN, 13.5 kN, and 30.5 kN, respectively. When the cone angle of the shrink tube increased from α = 5° to α = 25°, the increase in the MCF with different thicknesses was about 600%. The MCF was most affected by the cone angle, followed by the wall thickness, the friction coefficient, and the axial length of the friction cone. The change in the contact length of the friction cone of the shrink tube under different structural parameters was compared. The contact length decreased with the increase in tube wall thickness and increased with the increase in angle. The variation rule of MCF was obtained to provide a reference for the development of genealogical products.

Is longer axial length protective of vision-threatening diabetic retinopathy across different ages? A multicenter cohort of 736 patients

PurposeVision-threatening diabetic retinopathy (VTDR) included severe non-proliferative diabetic retinopathy (NPDR), proliferative diabetic retinopathy (PDR) and clinically significant diabetic macular edema (DME). To compare the axial length (AL) and assess its influence on VTDR across different ages.MethodsA retrospective cohort study. Medical chart review was performed in 736 consecutive patients with VTDR. The patients were divided into young (≤ 45 years) and elderly group (> 45 years) based on their age at the diagnosis of VTDR. After at least one year of standardized treatments, all eligible patients were followed up. The main outcome measures included the presence of tractional retinal detachment (TRD) involving foveal, final best-corrected visual acuity (BCVA), the development of neovascular glaucoma (NVG), and recurrent vitreous hemorrhage (VH) post-vitrectomy. ALs were compared between two age groups. The impact of AL on clinical outcomes was determined by logistic analyses after controlling for systemic parameters.ResultsThe study included 144 patients ≤ 45 years and 592 patients > 45 years. Young patients had significantly longer AL than elderly participants (23.9 mm vs 23.0 mm, p < 0.001). Over a median follow-up of 25.9 months, a larger proportion of young patients developed TRD (34.7% vs 16.2%, p < 0.001) and recurrent VH (18.6% vs 10.3%, p = 0.040) than elderly patients. In elderly group, longer AL is an independent protective factor in preventing TRD (odds ratio [OR], 0.5; 95% confidence interval [CI], 0.4–0.7; P < 0.001). However, this beneficial effect was not observed in young patients.ConclusionsYoung patients with VTDR exhibited significantly longer AL but more aggressive clinical signs with compromised prognosis. In elderly group, a longer AL independently reduced the risk of TRD, while this protective effect did not exist for young patients.

Characteristics of posterior precortical vitreous pockets visualized by swept-source OCT and en face OCT

To determine the characteristics of posterior precortical vitreous pockets (PPVPs) and to observe vitreous changes in myopic eyes by swept-source optical coherence tomography (SS-OCT) and en face imaging in a cohort of the Chinese Han population. This was a cross-sectional study. Volunteers (235 participants, 374 eyes) received an SS-OCT examination. The heights and widths of the PPVPs were measured by SS-OCT. The area of the PPVPs was measured on en face images. The relationships between PPVP size and sex, age, axial length (AL) and spherical equivalent (SE) were evaluated. The mean width and height were 6711.64 ± 1241.87 μm and 662.47 ± 326.39 μm, respectively. The area of the PPVPs was 30.296 ± 9.114 mm2. Boat-shaped, oval, and hook-shaped PPVPs were observed in 73.26%, 21.12%, and 5.62% of all eyes, respectively; 73.53% of all PPVPs had channels communicating with Cloquet’s tubes. There was a significant difference in the PPVP width among the participates over and under 50 years old (t = -2.508, P = 0.031). Age had a positive correlation with the PPVP width (r = 0.53, P = 0.001). The PPVP height showed significant differences among the different myopia groups (F = 3.618, P = 0.013). SE had a negative correlation with the PPVP height (r = -0.176, P = 0.001). However, there were no correlations between the AL and the width, height or area of the PPVPs (P = 0.117; P = 0.334; P = 0.057, respectively). Age and myopia affect the size of PPVPs. SS-OCT greatly facilitates visualization of the complex structure of the vitreous.

Changes and Influencing Factors of Corneal Endothelial Cells and Central Corneal Thickness after Pediatric Cataract Surgery.

This study aimed to examine the impact of cataract surgery on the corneal endothelium and central corneal thickness (CCT) in pediatric patients, and to identify the factors associated with corneal alterations. This retrospective study included consecutive children undergoing bilateral or unilateral cataract surgery and intraocular lens (IOL) implantation at the Eye Hospital of Wenzhou Medical University, with or without posterior capsulorhexis and anterior vitrectomy, and an age-matched normal control group. This study aimed to assess whether changes in corneal parameters, including CCT, corneal endothelial cell density (CD), average cell area (AVE), standard deviation of size (SD), coefficient of variation (CV), percentage of hexagonal cells (6A) before and after surgery, and endothelial cell loss (ECL) differed among the bilateral cataract, unilateral cataract, and control groups. Furthermore, the potential effects of anterior vitrectomy, axial length (AL), preoperative anterior chamber depth (ACD), surgical duration, horizontal corneal diameter (HCD), intraoperative pupil diameter (PD), and the number of corneal sutures on corneal endothelial parameters and CCT were investigated. A total of 107 eyes from 107 children were included in the study. In the bilateral cataract group, CD significantly decreased, AVE and CCT significantly increased, and ECL was significantly higher than in the control group. The unilateral cataract group also exhibited a significant increase in CCT. Additionally, the numberofcornealsutures was negatively correlated with CD, and PD was negatively correlated with CV in the unilateral cataract group. Cataract surgery in pediatric patients results in increased CCT, reduced CD, and morphological changes in corneal cells. A greater number of corneal sutures and a smaller PD increased the risk of CD reduction and elevated CV in the unilateral cataract group, underscoring the need for ophthalmologists to minimize corneal damage in these children.

Peripheral Iridectomy in Intrascleral Intraocular Lens Fixation: Preventing Reverse Pupillary Block

To compare clinical outcomes, reverse pupillary block (RPB) findings and anterior segment parameters in patients with and without intraoperative peripheral iridectomy during sutureless flattened flange intrascleral intraocular lens (IOL) fixation. Retrospective comparative case series. This study included 94 eyes of 82 patients who underwent IOL explantation due to vitreous-dislocated IOL at our clinic between March 2020 and September 2023, followed by flattened haptic-tipped IOL intrascleral fixation combined with pars plana vitrectomy (PPV). The patients were divided into two groups: Group 1 (n=54) underwent peripheral iridectomy during surgery, while Group 2 (n=40) did not undergo surgical peripheral iridectomy. Anterior chamber depth (ACD), anterior chamber angle (ACA) and white-to-white (WTW) distance were measured with Scheimpflug imaging. Visual outcomes, ACD, ACA, spherical equivalence (SE), intraocular pressure (IOP), complications, and secondary interventions were evaluated. There was no significant difference between the two groups preoperatively in terms of IOP, ACD, ACA, WTW distance, and axial length (p > 0.05). Postoperatively, the mean ACD was significantly less in Group 1 (3.79 ± 0.67 mm) than in Group 2 (4.11 ± 0.75 mm) (p = 0.03). Postoperative IOP was 15.51 ± 2.48 mmHg in group 1 and 18.20 ± 4.51 mmHg in group 2 (p < 0.001). The postoperative ACA was statistically significantly shallower in Group 1 (41.72 ± 3.47 degrees) than in Group 2 (52.45 ± 17.93 degrees) (p < 0.001). Postoperatively, RPB developed in 10 eyes (25.0%) in Group 2, while it was not observed in any patient in Group 1 (p < 0.001). In Group 2, pupillary capture developed in 4 cases (10%) in addition to RPB. Laser peripheral iridotomy was performed in cases with RPB. After laser peripheral iridotomy, mean IOP, mean ACA and ACD also decreased significantly (p < 0.001). Intraoperative peripheral iridectomy during scleral fixation surgery combined with PPV leads to significantly less RPB, a more stable anterior chamber, and fewer complications. Laser peripheral iridotomy was very useful in managing RPB that developed in the postoperative period.

Importance of different topographic, biometric, and retinal parameters for calculating IOL power

The objective is to evaluate the parameters significantly related to calculating the power of the implanted lens and to determine the importance of different biometric, retina, and corneal aberrations variables. A retrospective cross-sectional observational study used a database of 422 patients who underwent cataract surgery at the Oftalvist Center in Almeria between January 2021 and December 2022. A random forest based on machine learning techniques was proposed to classify the importance of preoperative variables for calculating IOL power. Correlations were explored between implanted IOL power and the most important variables in random forests. The importance of each variable was analyzed using the random forest technique, which established a ranking of feature selections based on different criteria. A positive correlation was found with the random forest variables. Selection: axial length (AL), keratometry preoperative, anterior chamber depth (ACD), measured from corneal epithelium to lens, corneal diameter, lens constant, and astigmatism aberration. The variables coma aberration (p-value = 0,12) and macular thickness (p-value = 0,10) were almost slightly significant. In cataract surgery, the implanted IOL power is mainly correlated with axial length, anterior chamber depth, corneal diameter, lens constant, and preoperative keratometry. New variables such as astigmatism and anterior coma aberration and retina variables such as the preoperative central macular thickness could be included in the new generation of biometric formulas based on artificial intelligence techniques.

Efficacy in myopia control-The impact of rebound.

When myopia control treatment is discontinued, progression will increase, but does it revert to expected values based on the age and race of the child or does it accelerate further? The latter scenario is considered a rebound. A PubMed search was conducted with the words 'rebound' and 'myopia control', identifying further papers from reviews. Inclusion was limited to prospective studies with ≥6 months of treatment, ≥3 months of data following cessation and with axial length data, which allowed calculation of rebound. Nineteen studies were identified, comprising 24 treatment groups. In 10 studies, untreated control children were followed both throughout the treatment and cessation periods, allowing for a concurrent comparison group. In three studies, a control group was followed for 1 or 2 years and thereafter received the treatment under evaluation. Later, treatment ceased in the originally treated children. Finally, six studies were cross-over designs. For these latter two study designs, initial axial elongation and myopia progression in the control group were extrapolated to the cessation period, accounting for annual slowing. Values from durations of <1 year were annualised. The mean annualised rebound was +0.05 ± 0.10 mm and -0.09 ± 0.24 D for axial length and myopia progression, respectively, and these were correlated (r2 = 0.59, p < 0.001). Rebound was associated with 1-year treatment efficacy (r2 = 0.43, p < 0.001). The mean annualised rebound with optical corrections was -0.01 ± 0.03 mm. Five of the six highest rebound values (≥0.14 mm) were from red light therapy and atropine studies. Rebound ranged from +0.03 to +0.14 mm for overnight orthokeratology. Consistent with previous statements, no evidence for rebound was found for myopia control spectacles and soft contact lenses. Future research should explore the influence of age and magnitude of treatment efficacy on rebound.

Genome-wide Meta-analysis for Myopic Macular Neovascularization Identified a Novel Susceptibility Locus and Revealed a Shared Genetic Susceptibility with Age-related Macular Degeneration.

To identify the susceptibility loci for myopic macular neovascularization (mMNV) in patients with high myopia. A genome-wide association study (GWAS) meta-analysis (meta-GWAS). We included 2,783 highly myopic individuals, including 608 patients with mMNV and 2,175 control participants without mMNV. We performed a meta-analysis of three independent GWASs conducted according to genotyping platform (Illumina Asian Screening Array [ASA] dataset, Illumina Human610 BeadChip [610K] dataset, and whole genome sequencing [WGS] dataset), adjusted for age, sex, axial length and the first to third principal components. We used DeltaSVM to evaluate the binding affinity of transcription factors to DNA sequences around the susceptibility single nucleotide polymorphisms (SNPs). In addition, we evaluated the contribution of previously reported age-related macular degeneration (AMD) susceptibility loci. The association between SNPs and mMNV in patients with high myopia. The meta-GWAS identified rs56257842 at TEX29 -LINC02337 as a novel susceptibility SNP for mMNV (odds ratio [OR]meta = 0.62, Pmeta = 4.63 × 10-8, I2 = 0.00), which was consistently associated with mMNV in all datasets (ORASA = 0.59, PASA = 1.71 × 10-4; OR610K = 0.63, P610K = 5.53 × 10-4; ORWGS = 0.66, PWGS = 4.38 × 10-2). Transcription factor-wide analysis showed that the transcription factors ZNF740 and EGR1 lost their binding affinity to this locus when rs56257842 had the C allele (alternative allele), and the WNT signaling-related transcription factor ZBTB33 gained binding affinity when rs56257842 had the C allele. When we examined the associations of AMD susceptibility loci, rs12720922 at CETP showed a statistically significant association with mMNV (ORmeta = 0.52, Pmeta = 1.55 × 10-5), while rs61871745 near ARMS2 showed a marginal association (ORmeta = 1.25, Pmeta =7.79 × 10-3). Our study identified a novel locus associated with mMNV in high myopia. Subsequent analyses offered important insights into the molecular biology of mMNV, providing the potential therapeutic targets for mMNV. Furthermore, our findings imply shared genetic susceptibility between mMNV and AMD.

Critical Impact of Working Distance on OCT Imaging: Correction of Optical Distortion and Its Effects on Measuring Retinal Curvature.

To assess the impact of working distance (WD) on optical distortion in optical coherence tomography (OCT) imaging and to evaluate the effectiveness of optical distortion correction in achieving consistent retinal Bruch's membrane (BM) layer curvature, regardless of variations in WD. Ten subjects underwent OCT imaging with four serial macular volume scans, each employing distinct WD settings adjusted by balancing the sample and reference arm of the OCT interferometer (eye length settings changed). Either of two types of 30° standard objectives (SOs) was used. A ray tracing model was used to correct optical distortion, and BM layer curvature (represented as the second derivative of the curve) was measured. Linear mixed effects (LME) modeling was used to analyze factors associated with BM layer curvature, both before and after distortion correction. WD exhibited significant associations with axial length (β = -1.35, P < 0.001), SO type (P < 0.001), and eye length settings (P < 0.001). After optical distortion correction, the mean ± SD BM layer curvature significantly increased from 16.80 ± 10.08µm-1 to 49.31 ± 7.50µm-1 (P < 0.001). The LME model showed a significant positive association between BM layer curvature and WD (β = 1.94, P < 0.001). After distortion correction, the percentage change in BM layer curvature due to a 1-mm WD alteration decreased from 9.75% to 0.25%. Correcting optical distortion in OCT imaging significantly mitigates the influence of WD on BM layer curvature, enabling a more accurate analysis of posterior eye morphology, especially when variations in WD are unavoidable.

Experimental study on thermal load characteristics of a U-bend pulse detonation combustor

The performance of pulse detonation turbine engines (PDTE) surpasses that of conventional turbine engines, primarily due to the pressure gain combustion process inherent in PDTE. A U-bend pulse detonation combustor (PDC) with a compact axial length was designed to meet the requirements of PDTE. However, the PDC introduces complex thermal management challenges. In this study, the wall temperature along the U-bend PDC was experimentally measured under various operating conditions, the thermal load characteristics were investigated. The results indicate that the external wall temperature increases monotonically with prolonged operation, whereas the internal wall temperature exhibits periodic fluctuations corresponding to the periodic filling and combustion process in the PDC. The temperature difference between the internal and external walls increases, then decreases over time, eventually fluctuates within a narrow temperature range. The wall temperature was observed to increase along the flow direction, peaking at 811 °C at 30 Hz at the location where the detonation wave is generated. Similarly, the heat flux of the PDC first increases, then decreases, and eventually reaches a constant value, indicating thermal equilibrium. The heat flux represents a significant energy loss, with the detonation section being the area of highest heat loss, reaching approximately 90.5 kW/m2 at 30 Hz.

Influence of metal on the far-exploding surface on fragment deformation behavior under contact explosion

Metals exhibit diverse failure behavior under impact loading. In the context of fragment warheads, preformed fragments also undergo fracture and crushing behaviors when subjected to explosive loading, potentially diminishing the terminal effect and damage capability of the warhead. To address this issue, metal disks of varying impedance were applied to the far-exploding surface of the fragments, and their influence on fragment deformation behavior was examined. The experimental results revealed that when metal disks were attached to the far-exploding surface of the fragments, their fracture behavior changed, and the recovered fragments remained intact axially. Additionally, the axial length of the recovered fragments decreased as the impedance of the metal disk on the far-exploding surface increased. To elucidate the underlying mechanism of this experimental phenomenon, the variation in fragment pressure during the propagation process was calculated by employing theories of planar detonation waves and shock wave propagation in the study. The results indicate that when the impedance of the metal disks on the far-exploding surface is higher than that of the fragments, it leads to an increase in internal pressure and the formation of a compression zone within the fragments, thereby preventing fragment fracture. Conversely, lower impedance results in the formation of a tensile effect within the fragments. The theoretical and experimental results were consistent. Finally, based on the dimensional analysis, the dimensionless models were established to predict fragment deformation and internal pressure values influenced by the metal disk on the far-exploding surface.

Acute effects of swimming goggle wearing on intraocular pressure, anterior chamber biometrics, and optic nerve head morphology

Swimming goggles (SG) are widely used in water sports, and this study aimed to evaluate the acute effects of wearing SG on intraocular pressure (IOP), anterior chamber biometrics, axial length (AL), and optic nerve head (ONH) morphology. Twenty-eight healthy young adults participated in this cross-sectional study, with assessed parameters including IOP, central corneal thickness (CCT), anterior chamber depth (ACD), anterior chamber angle (ACA), AL, and optical coherence tomography (OCT) imaging of the ONH, specifically Bruch membrane opening (BMO), Bruch membrane opening-minimum rim width (BMO-MRW), lamina cribrosa depth (LCD), and prelaminar tissue (PLT). Measurements were taken at four time points: before wearing SG, at the 1st and 10th minutes of wearing, and immediately after removal. The results showed a significant increase in IOP at the 1st and 10th minutes of SG wear compared to pre-wear and post-removal values. Additionally, decreases in CCT, ACD, and ACA, along with an increase in AL, were observed while wearing SG. However, these changes reverted to baseline after the goggles were removed. No significant alterations were detected in ONH parameters during the study. The findings suggest that wearing SG induces an acute rise in IOP and changes in anterior segment parameters, likely due to oculopression, but does not appear to affect ONH morphology in the short term. Further studies are needed to investigate any potential long-term effects.

Effects of Stress and Strain on the Optic Nerve Head on the Progression of Glaucoma.

In primary open-angle glaucoma, the rate of retinal nerve fiber layer thickness decrease was negatively correlated with lamina cribrosa strain, which was associated with intraocular pressure and optic nerve head geometric factors. We hypothesized that the biomechanical deformation of the optic nerve head (ONH) contributes to the progression of primary open-angle glaucoma (POAG). This study investigated the biomechanical stress and strain on the ONH in patients with POAG using computer simulations based on finite element analysis (FEA) and analyzed its association with disease progression. We conducted a retrospective analysis that included patients diagnosed with early-to-moderate stage POAG. The strains and stresses on the retinal nerve fiber layer (RNFL) surface, prelaminar region, and lamina cribrosa (LC) were calculated using computer simulations based on FEA. The correlations between the rate of RNFL thickness decrease and biomechanical stress and strain were investigated in both the progression and non-progression groups. The study included 71 and 47 patients in the progression and non-progression groups, respectively. In the progression group, the factors exhibiting negative correlations with the RNFL thickness decrease rate included the maximum and mean strain on the LC. In multivariate analysis, the mean strain on the LC was associated with optic disc radius, optic cup deepening, axial length, and mean intraocular pressure (IOP), whereas the maximum strain was only associated with mean IOP. In early-to-moderate stage POAG, the rate of RNFL thickness decrease was influenced by both the mean and maximum strain on the LC. Strains on the LC were associated with mean IOP, optic disc radius, axial length, and optic cup deepening. These results suggest that not only IOP but also ONH geometric factors are important in the progression of glaucoma.