- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
Repeatability assessment of biometric measurements with different refractive states and age using a swept-source biometer
摘要： Background: We aim to assess if refractive error or age may influence the repeatability of measurements using a swept-source biometer. Methods: A total of 61 subjects were evaluated with IOLMaster 700 acquiring measurements of axial length (AL), central corneal thickness (CCT), white-to-white distance (WTW), anterior aqueous depth (AQD), lens thickness (LT), and keratometry (K) readings. Repeatability was evaluated classifying the sample according to the refractive state and age by the calculation of the within-subject standard deviation (Sw), coefficient of repeatability, and intraclass correlation coefficient. Results: Very similar Sw was acquired among groups for AL, CCT, and WTW. Differences found for AQD, LT, keratometry and astigmatism among refractive and age groups were not clinically significant. Refractive groups obtained a Sw for AQD between 0.016 and 0.026, while for LT was between 0.023 and 0.029 mm. Besides, Sw showed values from 0.014 to 0.029 mm for keratometry. Age groups obtained a Sw of 0.025 and 0.016 mm for AQD, and 0.029 and 0.018 mm for LT, respectively. Sw was 0.019 vs 0.018 mm for K1, 0.014 vs 0.031 mm for K2. Conclusions: IOLMaster 700 showed good repeatability for biometric and keratometric parameters in eyes classified according to their refractive error or age.
关键词： anterior segment,Repeatability,biometry,swept-source biometer,refractive error,age
更新于2025-09-23 15:23:52
-
Rapid calculation of bespoke body segment parameters using 3D infra-red scanning
摘要： Body segment parameters such as segment mass, centre of mass and moment of inertia, serve as important inputs for musculoskeletal modelling. These parameters are normally derived from regression tables; however, can be poorly representative of the study population with variations of up to 40% recorded between different tables. More recent methods, such as 3D scanning, present a rapid and accurate way to produce subject-specific body segment parameters for use in musculoskeletal models. An infra-red 3D scanner was used to produce full-body scans of 95 males and females. Each was put through an algorithm to calculate bespoke segment mass, centre of mass and inertial properties for each segment of the body, with results comparable to cadaveric data. These methods could be used to increase the specificity of musculoskeletal modelling outputs for individual subjects, improving the accuracy of modelling outputs in biomechanics-related research.
关键词： Musculoskeletal modelling,3-dimensional scanning,Moments of inertia,Body segment parameter
更新于2025-09-23 15:23:52
-
Early Onset Ultrastructural and Functional Defects in RPE and Photoreceptors of a Stargardt-Like Macular Dystrophy (STGD3) Transgenic Mouse Model
摘要： PURPOSE. We investigated the interplay between photoreceptors expressing mutant ELOVL4 (responsible for Stargardt-like disease, STGD3) and RPE in the initial stages of retinal degeneration. METHODS. Using electron microscopy and electroretinogram (ERG), we assessed RPE and photoreceptor ultrastructure and function in transgenic ELOVL4 (TG1-2 line; TG) and wild-type (WT) littermates. Experiments were done at P30, 1 month before photoreceptor loss in TG and at P90, a time point with approximately 30% rod loss. To further elucidate the mechanism underlying our ultrastructural and functional results, we undertook Western blotting and immunohistochemistry of key proteins involved in phagocytosis of outer segments by RPE cells. RESULTS. Firstly, we showed that in TG mouse photoreceptors, endogenous ELOVL4 protein is not mislocalized in the presence of the mutated ELOVL4 protein. Secondly, we found evidence of RPE toxicity at P30, preceding any photoreceptor loss. Pathology in RPE cells was exacerbated at P90. Furthermore, higher proportions of phagosomes remained at the apical side of RPE cells. Subretinal lysosomal deposits were immunopositive for phagocytic proteins. Ultrastructural analysis of photoreceptor (rod) outer segments showed disrupted surface morphology consisting of disc spacing irregularities. Finally, rods and RPE exhibited signs of dysfunction as measured by the ERG a-wave leading edge (P30) and c-wave (P90), respectively. CONCLUSIONS. The presence of human mutant ELOVL4 in transgenic mouse photoreceptors leads to early outer segment disc pathology and RPE cytotoxicity. Defective processing of these abnormal discs by RPE cells ultimately may be responsible for outer segment truncation, photoreceptor death, and vision loss.
关键词： mouse,outer segment,Stargardt-like dystrophy,photoreceptor,STGD3,phagocytosis,ELOVL4,RPE
更新于2025-09-23 15:23:52
-
Scleral Thinning After Repeated Intravitreal Injections of Antivascular Endothelial Growth Factor Agents in the Same Quadrant
摘要： PURPOSE. We assessed the effects of intravitreal anti-vascular endothelial growth factor (anti-VEGF) therapy on scleral architecture using spectral domain anterior segment optical coherence tomography (OCT). METHODS. A total of 35 eyes of 35 patients treated with at least 30 intravitreal injections in one eye in the inferotemporal quadrant with ranibizumab or a?ibercept and 10 or less intravitreal injections in the fellow eye attending the intravitreal injection clinic were included. Enhanced depth imaging anterior segment OCT was used to measure scleral thickness. For each eye the sclera was measured in four quadrants at 3 mm from the limbus. In addition axial eye length was measured in all subjects using partial coherence interferometry. RESULTS. The mean number of intravitreal injections was 42 (range, 30–73) and 1.6 (range, 0–9) in the fellow eyes. In the study eyes with more than 30 injections the average scleral thickness in the inferotemporal quadrant was 568.4 lm (SD 6 66 lm) and 590.6 lm (SD 6 75 lm) in the fellow eyes with 10 or less injections (P ? 0.003). The mean average scleral thickness in the other three quadrants (inferonasal, superotemporal, and superonasal) was 536.6 lm in the study eyes (SD 6 100 lm) and 545.2 lm (SD 6 109 lm) in the fellow eyes (P ? 0.22). There was a borderline association of the total number of injections with scleral thickness change in the inferotemporal quadrant (r ? 0.3, P ? 0.052). CONCLUSIONS. Intravitreal injections may lead to scleral changes when applied repeatedly in the same quadrant. Thus, alternating the injection site should be considered in patients requiring multiple intravitreal injections.
关键词： retina,anterior segment OCT,anti-VEGF,intravitreal injections,sclera
更新于2025-09-23 15:23:52
-
[IEEE 2018 Eleventh International Conference "Management of large-scale system development" (MLSD 2018) - Moscow (2018.10.1-2018.10.3)] 2018 Eleventh International Conference "Management of large-scale system development" (MLSD - Optimization of the Structure and Parameters of the Light Cycle Aimed at Improving Traffic Safety at an Intersection
摘要： Formulas for evaluating structural safety for an arbitrary scheme of the road network segment are proposed. On their basis the problem of structural optimization of the traffic light cycle aimed at improving traffic safety is set. The similar optimization problem with respect to traffic intensity is set as well. Approaches to their solution are offered.
关键词： scheme of phase separation,microscopic models of traffic flows,optimization,safety of the road network segment,controlled intersection,computational experiments
更新于2025-09-23 15:22:29
-
[IEEE 2018 3rd International Conference for Convergence in Technology (I2CT) - Pune (2018.4.6-2018.4.8)] 2018 3rd International Conference for Convergence in Technology (I2CT) - Modified Level-Set for Segmenting Breast Tumor from Thermal Images
摘要： Contactless, painless and radiation-free thermal imaging technique is one of the preferred screening modalities for detection of breast cancer. However, poor signal to noise ratio and the inexorable need to preserve edges defining cancer cells and normal cells, make the segmentation process difficult and hence unsuitable for computer aided diagnosis of breast cancer. This work uses a modified version of level-set called marker-controlled level-set for segmentation along with pre-processing. This paper presents key findings from a research conducted on the appraisal of two promising techniques, for the detection of breast cancer: a) marker-controlled Level-set segmentation of anisotropic diffusion filtered preprocessed image versus b) Segmentation using marker-controlled level-set on a Gaussian-filtered image. The proposed method was carried out on images from an online database with samples collected from women of varying breast characteristics. It was observed that the breast was able to be segmented out from the background by adjustment of the markers. From the results, it was observed that as a pre-processing technique, anisotropic filtering with level-set segmentation, preserved the edges more effectively than Gaussian filtering. Segmented image, by application of anisotropic filtering was found to be more suitable for feature extraction, enabling automated computer aided diagnosis of breast cancer.
关键词： Breast,Thermograms,Gaussian,Anisotropic diffusion,Segment,Level set
更新于2025-09-23 15:22:29
-
Anterior segment optical coherence tomography (AS-OCT) as a new method of detecting copper deposits forming the Kayser-Fleischer ring in patients with Wilson disease
摘要： Purpose: Kayser–Fleischer ring pathognomonic for Wilson disease (WD) is formed of corneal copper deposits present predominantly within the anterior chamber angle at the Schwalbe’s line. The slit-lamp assessment commonly used as a standard of care cannot detect them early enough, as the angle view is obscured by the corneal limbus. The aim of the research was to evaluate the anterior segment optical coherence tomography (AS-OCT), as objective diagnostic assessment of copper deposits forming KF ring in patients with WD. Methods: Twenty-nine subjects (17 women) and twenty-nine controls (14 women) were enrolled and underwent slit lamp and AS-OCT assessment. Results: Kayser–Fleischer ring was not detected – either with a slit lamp or with AS-OCT – in any of the controls. Fifteen subjects presenting without KF ring at a slit-lamp examination were found to have a KF ring when examined with AS-OCT (p < 0.001), which confirms improved accuracy of AS-OCT, as compared to the slit-lamp examination. Conclusion: Our results support AS-OCT as a diagnostic procedure to offer better objectivity and accuracy as compared to a slit-lamp examination, both at the diagnostic stage and when monitoring changes in KF ring during medical therapy to assess its efficacy and patient compliance.
关键词： anterior segment optical coherence tomography,Kayser–Fleischer ring,Wilson disease,copper deposit
更新于2025-09-23 15:22:29
-
Estimation of Intraocular Lens Power Calculation after Myopic Corneal Refractive Surgery: Using Corneal Height in Anterior Segment Optical Coherence Tomography
摘要： Purpose: To investigate the feasibility of estimating effective lens position (ELP) and calculating intraocular lens power using corneal height (CH), as measured using anterior segment optical coherence tomography (AS-OCT), in patients who have undergone corneal refractive surgery. Methods: This study included 23 patients (30 eyes) who have undergone myopic corneal refractive surgery and subsequent successful cataract surgery. The CH was measured with AS-OCT, and the measured ELP (ELPm) was calculated. Intraocular lens power, which could achieve actual emmetropia (Preal), was determined with medical records. Estimated ELP (ELPest) was back-calculated using Preal, axial length, and keratometric value through the SRK/T formula. After searching the best-fit regression formula between ELPm and ELPest, converted ELP and intraocular lens power (ELPconv, Pconv) were obtained and then compared to ELPest and Preal, respectively. The proportion of eyes within a defined error was investigated. Results: Mean CH, ELPest, and ELPm were 3.71 ± 0.23, 7.74 ± 1.09, 5.78 ± 0.26 mm, respectively. The ELPm and ELPest were linearly correlated (ELPest = 1.841 × ELPm – 2.018, p = 0.023, R = 0.410) and ELPconv and Pconv agreed well with ELPest and Preal, respectively. Eyes within ±0.5, ±1.0, ±1.5, and ±2.0 diopters of the calculated Pconv, were 23.3%, 66.6%, 83.3%, and 100.0%, respectively. Conclusions: Intraocular lens power calculation using CH measured with AS-OCT shows comparable accuracy to several conventional methods in eyes following corneal refractive surgery.
关键词： Intraocular lens power calculation,Corneal height,Corneal refractive surgery,Effective lens position,Anterior segment optical coherence tomography
更新于2025-09-23 15:22:29
-
Numerical analysis of brilliance and coherent photon flux of segmented undulator radiation based on statistical optics
摘要： A method based on wave optics together with electron tracking is used to analyze synchrotron radiation from a segmented undulator in a double or multi mini-β function lattice storage ring. Radiation brilliance and transverse coherence features are investigated, where the former is calculated with the Wigner distribution function and the latter is evaluated by integrating the photon flux and cross-spectral density to exhibit the coherent flux and overall degree of coherence. To be specific, radiation properties for a single undulator in a typically single mini-β function and a tandem undulator in a double mini-βy lattice are compared in this work. As a result, both, brilliance and coherent flux can be enhanced by a second tandem undulator at the Taiwan Photon Source.
关键词： Wigner distribution function,transverse coherence,segment undulator.,double mini-βy lattice,brilliance
更新于2025-09-23 15:22:29
-
Haab striae: Optical coherence tomographic analysis
摘要： Purpose. — To study Haab striae in adults with primary congenital glaucoma and describe them by anterior segment optical coherence tomography, as well as analyze their evolution over the patient’s lifetime. Material and methods. — Three patients with primary congenital glaucoma were recruited, aged between 17 and 48 years old, with incidentally noted Haab striae on glaucoma consultation. They were studied by: slit lamp; anterior segment optical coherence tomography, Heidelberg Engineering Inc., Germany, (with anterior segment module) and Cirrus HD-OCT, Carl Zeiss Meditec, Dublin, California, USA (with 3D reconstruction); and specular biomicroscopy. The results obtained were contrasted with other studies performed in children. Results. — Rounded excrescences protruding towards the anterior chamber were found, as well as dense, irregular tissue between them. In addition, endothelial abnormalities (polymegathism and polymorphism) were found. These findings fit the evolution of those obtained in pediatric studies and remain stable in adult life. Conclusions. — Through noninvasive methods such as optical coherence tomography and specular biomicroscopy, it is possible to make the diagnosis and follow up these patients. The findings suggest posterior corneal topographic changes; additional studies on this subject may be necessary.
关键词： Haab striae,Primary congenital glaucoma,Anterior segment optical coherence tomography,Corneal endothelium,Specular biomicroscopy
更新于2025-09-23 15:22:29