Tomey Corporation

Corneal thickness measurements with the RTVue, Casia-2, and Pentacam devices in patients with mild-to-moderate keratoconus: a comparative study

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Background To compare the characteristics of corneal thickness measurements among the RTVue, Casia-2, and Pentacam in patients with mild-to-moderate keratoconus. Methods We recruited 46 eyes of 46 patients diagnosed with mild-to-moderate keratoconus at our hospital between January and March 2022. The central corneal thickness (CCT) and thinnest corneal thickness (TCT) were measured using two optical coherence tomography (OCT) instruments (RTVue and Casia-2) and the more conventional Pentacam. Differences and correlations between the CCTs and TCTs, based on the device and influencing factors, were explored. Results The CCTs were highly consistent among the groups (p = 0.434) and correlated with one another (p < 0.001). The TCTs measured by OCTs were thinner than those measured by the Pentacam (p < 0.001); however, all three devices were highly correlated (p < 0.001). The thinnest point location measurements with RTVue and Casia-2 differed significantly from ...

Lens structure segmentation from AS-OCT images via shape-based learning

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Background and objectives The lens is one of the important refractive media in the eyeball. Abnormality of the nucleus or cortex in the lens can lead to ocular disorders such as cataracts and presbyopia. To achieve an accurate diagnosis, segmentation of these ocular structures from anterior segment optical coherence tomography (AS-OCT) is essential. However, weak-contrast boundaries of the object in the images present a challenge for accurate segmentation. The state-of-the-art (SOTA) methods, such as U-Net, treat segmentation as a binary classification of pixels, which cannot handle pixels on weak-contrast boundaries well. Methods In this paper, we propose to incorporate shape prior into a deep learning framework for accurate nucleus and cortex segmentation. Specifically, we propose to learn a level set function, whose zero-level set represents the object boundary, through a convolutional neural network. Moreover, we design a novel shape-based loss function, where the shape prior...

Validation of Interleukins and Other Cytokines Together With OCT Imaging for Rapid Infectious Keratitis Assessment

As conventional corneal scraping with bacterial culturing has several disadvantages such as long duration until diagnosis, invasiveness and lacks alternatives, there is demand for a novel non-invasive, rapid test in keratitis management. First aim of this study will be to evaluate the influence of TNF-alpha on Gram+ and Gram- bacteria causing keratitis. Second aim of this study will be to develop an algorithm, that should help to distinguish between different pathogens causing keratitis. ( Read Full Article )

Success Rate of Swept-Source Optical Coherence Tomography Biometry of Eyes of Elementary School Students

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Purpose: To determine the success rate of swept-source optical coherence tomography (SS-OCT) biometry (OA-2000) in elementary school students. Methods: This was a prospective observational longitudinal study of 115 right eyes of elementary school students who were 8- to 9-years-old at the initial examination. Biometric measurements of the eyes were performed annually for three years, viz., during the third, fourth, and fifth grades. The success rates of obtaining data from optical biometric measurements of the axial length (AL), central corneal thickness (CCT), anterior chamber depth (ACD), lens thickness (LT), pupillary diameter (PD), corneal diameter (CD), and corneal curvature (CC) were determined. Results: The AL, CCT, and CC could be measured in all images at the three measurement times in all subjects. The success rate of the measurements of the ACD was 92.2% in the third grade and 100% in the fourth and fifth grade. The LT was successfully measured in...

Evaluation of the repeatability of optical coherence tomography in patients with age-related cataract associated with dry eye

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Aim To assess the repeatability of a new optical biometer (OA-2000, Tomey, Japan) based on swept-source optical coherence tomography (SS-OCT) and Placido-disk topography in dry eyes with cataracts. Method A cross-sectional study was performed. Two hundred sixteen eyes of 216 cataract patients were enrolled in our hospital from March 2020 to December 2020. According to the subjective symptoms and objective examination of dry eye, the patients were assigned to dry eye group and non-dry eye group. Axial length (AL), keratometry readings (K), lens thickness (LT), anterior chamber depth (ACD), central corneal thickness (CCT) and white-to-white (WTW) distance were measured by one skilled operator. The repeatability of each parameter based on within-subject standard deviation (Sw), repeatability limit of standard deviation (2.77Sw), coefficient of variation (CoV) and intra-class correlation coefficient (ICC) was evaluated. Result There was no significant difference in age and gender betwee...

Corneal Biometric Features and Their Association With Axial Length in High Myopia

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Purpose To characterize the morphologic features of corneal parameters and their correlation with axial length (AL) elongation in patients with high axial myopia. Design Cross-sectional comparative study. Methods A total of 299 eyes with high myopia (299 patients) and 266 eyes of age- and sex-matched control subjects (266 patients) were examined by anterior segment swept-source optical coherence tomography (SS-OCT) and an IOL Master. Central corneal thickness (CCT), thinnest corneal thickness (TCT), corneal volume (CV), and anterior corneal curvature (CC), posterior CC, and total CC were obtained, and their correlation with AL was investigated using multiple linear regression model. Results The CCT, TCT, CV, and anterior, posterior, and total CC of patients with high myopia were smaller than those of the control subjects. The CCT, TCT, and CV had a continuous downward trend with AL. However, CC decreased rapidly with AL when AL was <26 mm and the slope decreased when AL was 26 to...

Agreement Between Two Swept-source Optical Coherence Tomography Biometers and A Partial Coherence Interferometer

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Purpose To evaluate the level of agreement between ANTERION (Heidelberg Engineering, Heidelberg, Germany), OA-2000 (Tomey, Nagoya, Japan), and IOL Master 500 (Carl Zeiss Meditec AG, Jena, Germany). Methods Fifty-one eyes of 51 patients were included in the study. Flat and steep keratometry (K), vector component of astigmatism (J0 and J45), anterior chamber depth (ACD), and axial length (AL) were compared using the three devices. Repeated-measures analysis of variance was conducted to compare the mean values of the biometrics. Pearson’s correlation test was conducted to analyze the correlations of the measured values, and a Bland–Altman plot was used to assess the agreement between the three devices. The predicted intraocular lens (IOL) power of each device was compared to the others using the SRK/T, Haigis, Barrett Universal II, and Kane formulas. Result s: All K values measured using ANTERION were flatter than those of other instruments. However, good agreement was obse...

Comparison of Anterior Segment Measurements with a New Multifunctional Unit and Five Other Devices

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Purpose To evaluate the clinical availability of a multifunctional ocular biometric unit, MR-6000 (Tomey Corporation, Nagoya, Japan), for simultaneous keratometry, tonometry, topography, and pachymetry evaluation, and compare anterior segment measurements with five other devices: autokeratometer (KR-1, Topcon, Tokyo, Japan), Scheimpflug camera (Pentacam HR, Oculus, Wetzlar, Germany), swept-source optical coherence tomography (IOLMaster 700, Carl Zeiss, Oberkochen, Germany), Placido disk scanning-slit topography (Orbscan II, Bausch & Lomb, NY, USA), and noncontact tonometry (FT-1000, Tomey Corporation). Methods Thirty patients (30 eyes) who visited our clinic for cataract surgery were examined using MR-6000 and the other devices. The mean keratometry (Km), central corneal thickness (CCT), white-to-white (WTW) distance, and intraocular pressure (IOP) values were compared. Repeated measures analysis of variance, Wilcoxon signed rank test, intraclass correlation coefficient (ICC), a...

Detection of Anterior Hyaloid Membrane Detachment Using Deep-Range Anterior Segment Optical Coherence Tomography

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The visibility of anterior hyaloid membrane (AHM) and Berger's space in phakic eyes was investigated. In 624 eyes of 624 patients, the retrolental space was scanned with the deep-range anterior segment optical coherence tomography (AS-OCT, CASIA2, Tomey). Subgroup analysis was conducted in 223 eyes undergoing cataract surgery. The logistic regression analysis using the backward-elimination method was performed to evaluate the influence of various factors on the visibility of AHM (dependent variable). Explanatory variables included age, gender, axial length, corneal power, corneal cylinder, and the Co III gradings. Intrarater repeatability for AHM visibility was excellent with the prevalence-adjusted bias-adjusted kappa (κ coefficient) of 0.90. AHM was observed in 43 eyes (6.9%). The patients with visible AHM (68.1 ± 8.8 years) were significantly older than those without visible AHM (52.6 ± 25.6 years) ( p &lt; 0.001). The logistic regression analysis in the c...

Evaluation of the Relationship Between the Changes in the Corneal Biomechanical Properties and Changes in the Anterior Segment OCT Parameters Following Customized Corneal Cross-Linking

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Purpose: This study aimed to investigate the relationship between changes in corneal biomechanical properties and changes in anterior segment optical coherence tomography (AS-OCT) parameters preoperatively and following customized corneal cross-linking (C-CXL) in eyes with progressive keratoconus. Patients and Methods: This study included 44 eyes of 44 patients (33 men, 11 women; average age 22.8 ± 6.4 years) who underwent C-CXL for progressive keratoconus. Scheimpflug-based tonometer (SBT) and AS-OCT findings were evaluated preoperatively and 3 months following CXL. Parameters related to changes in SBT parameters were examined by multiple regression analysis using the stepwise method. Results: Regarding SBT parameters, significant changes were observed in the integrated area under the curve of the inverse concave radius (pre, 12.19 ± 1.95/mm; post, 11.26 ± 1.89/mm; p < 0.0001), maximum inverse radius (pre, 0.24 ± 0.04/mm; post, 0.23 ± 0.04/mm; ...

Characteristics of Anterior Segment in Congenital Ectopia Lentis: An SS-OCT Study

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Purpose . To investigate the characteristics of anterior chamber angle parameters in congenital ectopia lentis (CEL) patients and to evaluate the sensitivity and specificity of anterior segment parameters in distinguishing CEL from healthy controls. Setting . Zhongshan Ophthalmic Center, Guangzhou, China. Design . Cross-sectional study. Methods . 35 CEL patients and 35 age- and sex-matched healthy controls were recruited. Axial length (AL) and anterior segment parameters including anterior chamber width (ACW), angle open distance (AOD), angle recess area (ARA), trabecular-iris space area (TISA), and trabecular-iris angle (TIA) were measured. All the above parameters and the ratio index of angle parameters, which was defined as the angle parameter value of the narrower side to that of the contralateral side, were compared between CEL and controls. Receiver operating characteristic (ROC) curves were also plotted to evaluate the diagnostic performance of anterior chamber angle paramete...

Tilt and decentration of posterior and anterior iris-claw intraocular lenses: a pilot study using anterior segment optical coherence tomography

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Background Information on the centration and tilt of iris-claw intraocular lenses (IC-IOLs) is limited. In this study, we tested the capacity of an anterior segment optical coherence tomography (AS-OCT) instrument to measure decentration and tilt of anterior and posterior IC-IOLs through an integrated software. Methods The present observational, cross-sectional study was conducted at University Eye Clinic of Parma (Parma, Italy). The CASIA2 swept-source AS-OCT (Tomey Corp.) was used to measure the tilt and decentration of posterior and anterior IC-IOLs in patients implanted at least 6 months in advance. After failure with full-automation, semi-manual IOL tracing was applied. In-the-bag (IB) contralateral IOLs, when present, were measured automatically. The Bland-Altman method was used to evaluate the agreement between repeated measurements (2 images for each study eye). The amount and direction of tilt and decentration were recorded and plotted into polar charts for evaluatio...

Defining the Clinical Role of Swept-Source Anterior Segment Optical Coherence Tomography in Eyes Undergoing Strabismus Surgery

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Purpose: To describe the clinical role of swept-source anterior segment optical coherence tomography in extraocular muscle imaging in various strabismic conditions. Study Design: Prospective observational study. Participants: A total of 1104 extraocular muscles of 150 subjects were imaged. Normal eyes (640 muscles), eyes undergoing re-operation (240 muscles), paralytic strabismic eyes (16 muscles), non-paralytic strabismic eyes (20 muscles), post-traumatic strabismic eyes (64 muscles), eyes with thyroid disease (64 muscles), and other atypical cases (60 muscles) were imaged. In all cases, up to four recti muscles were evaluated in a given eye depending on the need. Results: The mean age was 38.15 ± 16.25 years. Overall, muscle insertion was identified in over 90% of the subjects. Apart from normal muscles (n = 860, 93.68%), the location was identified in previously operated eyes (n = 54, 90%), in traumatic muscle slippage (n = 2, 11.11%), in ocular coat ectasia (n = 11, 91.66...

Effect of Light Conditions and Accommodation on Implantable Phakic Contact Lens Vault by Anterior Segment Optical Coherence Tomography

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Purpose: To investigate the dynamic pupil and vault changes in eyes with implantable phakic contact lens (IPCL) under photopic and scotopic settings, as well as during accommodation using the anterior segment optical coherence tomography (AS-OCT). Methods: A prospective observational study included consecutive 36 eyes of myopic patients who underwent IPCL V2.0 implantation. Under photopic and scotopic light settings, as well as during accommodation, all patients were scanned using CASIA OCT (CASIA2; TOMEY, Nagoya, Japan). The pupil size, the vault (distance between the back surface of the IPCL and the anterior lens capsule), ACD-lens (distance between the posterior corneal surface and the anterior lens surface), IPCL-lens (distance between the posterior corneal surface and the anterior IPCL surface), and lens thickness (LT) were the study parameters. Results: The vault was significantly lower under photopic conditions ( p -value< 0.001). The pupil size was significantly smaller i...

Assessment of Anterior Uveitis Through Anterior-Segment Optical Coherence Tomography and Artificial Intelligence-Based Image Analyses

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Purpose : The purpose of this study was to develop an automated artificial intelligence (AI) based method to quantify inflammation in the anterior chamber (AC) using anterior-segment optical coherence tomography (AS-OCT) and to explore the correlation between AI assisted AS-OCT based inflammation analyses and clinical grading of anterior uveitis by Standardization of Uveitis Nomenclature (SUN). Methods : A prospective double blinded study of AS-OCT images of 32 eyes of 19 patients acquired by Tomey CASIA-II. OCT images were analyzed with proprietary AI-based software. Anatomic boundaries of the AC were segmented automatically by the AI software and Spearman's rank correlation between parameters related to AC cellular inflammation were calculated. Results : No significant (p = 0.6602) differences were found between the analyzed AC areas between samples of the different SUN grading, suggesting accurate and unbiased border detection/AC segmentation. Segmented AC areas were processed by...

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