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Non-ionized, High-resolution Measurement of Internal and Marginal Discrepancies of Dental Prosthesis Using Optical Coherence Tomography
摘要： An internal and marginal fit between prosthesis and abutment are important factors of the durability of dental prosthesis. In this study we have proposed the use of swept-source optical coherence tomography (SS-OCT) as a novel application for non-ionized and high-resolution measurements of internal and marginal discrepancies at anatomically critical four points, such as occlusal, angle, axial, and margin during prosthesis attachment. A tooth model was fabricated by 3D printing technique and the dental prosthesis was designed using dental CAD software. The cross-sectional images along with intensity peak profile analysis of the sample were acquired using OCT system for measurements of fit. The demonstrated qualitative and quantitative evaluations can be well-utilized for assessment of the internal and marginal fit of dental prosthesis.
关键词： Intensity analysis,Dental prosthesis,Internal and marginal fit,Swept-source optical coherence tomography
更新于2025-09-23 15:23:52
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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
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Biometry in cataract surgery
摘要： Purpose of review To review the literature in 2017 and 2018 pertaining to biometry for cataract surgery and report pertinent findings. Recent findings New devices using swept-source ocular coherence tomography can measure axial length in dense cataracts more frequently than common biometers. Computer-assisted registration may be superior to intraoperative aberrometry for toric intraocular lens (IOL) placement. Soft contact lenses may not require removal as long before biometry as previously thought. The Barrett Universal II IOL formula has been found to perform well at all axial lengths. Summary New swept-source ocular coherence tomography biometers are more frequently successful at measuring axial length in dense cataracts which promises to improve refractive outcomes. Accuracy in toric IOL placement is likely to increase with improved devices. It may not be necessary to have patients remove soft contact lens any more than 2 days prior to biometry. The Barrett Universal II IOL formula may be used confidently for most eyes. Advancements acknowledged, purchasing new equipment will not be necessary for all surgeons.
关键词： swept-source ocular coherence tomography,toric,cataract,biometry
更新于2025-09-23 15:23:52
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Posterior Vitreous Structures Evaluated by Swept-source Optical Coherence Tomography with En Face Imaging
摘要： Purpose: To evaluate posterior vitreous structures using swept-source (SS) optical coherence tomography (OCT) with en face imaging. Methods: We retrospectively reviewed OCT images of healthy individuals who did not have intra-ocular disease. We obtained high-definition horizontal and vertical line scans crossing the fovea and 3D scans using SS-OCT, with the 3D scan centered between the fovea and the optic-nerve head. An enhanced vitreous visualization function was used to highlight vitreous structures. En face mode was used to measure the area of Martegiani (AM) and bursa premacularis (BP). We performed all measurements using a built-in function of the viewing software. Results: We enrolled 24 eyes from 12 healthy individuals. The mean patient age was 28.7 ± 4.6 years (range, 24 to 39 years). The mean AM and BP areas were 5.73 ± 0.88 and 18.76 ± 6.95 mm2, respectively. In en face imaging, AM shape was most frequently a vertical oval (18 / 22, 81.8%), while the predominant BP shape was round (16 / 20, 80.0%). AM was in contact with the optic disc, either at the temporal-disc margin (13 eyes, 59.1%) or the nasal optic-disc margin (9 eyes, 40.9%). Conclusions: Posterior vitreous structures, such as AM and BP, were readily visualized using en face imaging with SS-OCT. Investigating normal vitreous configuration might help in understanding changes in vitreous structures associated with retinal pathology.
关键词： Area of Martegiani,Bursa premacularis,En face,Swept-source optical coherence tomography,Vitreous body
更新于2025-09-23 15:22:29
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Swept source optical coherence tomography analysis of choroidal thickness in macular telangiectasia type 2: a case-control study
摘要： Purpose There has been a recent interest in the association of macular telangiectasia (MacTel) type 2 with central serous choroidopathy and other pachychoroid disorders. This study was performed to assess the subfoveal choroidal thickness (SFCT) in patients with MacTel type 2 and compare it with healthy controls using swept source optical coherence tomography (SS-OCT). Methods It was a retrospective case-control study performed at a tertiary eye care center. The cases constituted patients with MacTel type 2 detected over the last 2 years (April 2016 to March 2018). The controls were healthy adults with no posterior segment pathology. The patients were evaluated with color fundus photography, SS-OCT (Triton, Topcon Inc., Oakland, New Jersey, USA) and fundus fluorescein angiography. The cases were staged based on Gass and Blodi classification. SFCT was compared between the two groups. Results Sixty-five eyes of 33 patients with MacTel were included. The controls consisted of 61 eyes of 33 healthy age-matched (p = 0.81) and sex-matched (p = 0.31) adults. The mean SFCT in cases (353.0 ± 91.2 μm) was higher than controls (289.2 ± 69.0 μm), and this difference was statistically significant (p = 0.0001). The mean SFCT was different in various stages: 346.6 ± 86.3 μm (stage 2), 334.6 ± 90.2 μm (stage 3), 374.6 ± 94.0 μm (stage 4), and 294.8 ± 68.8 μm (stage 5), though this was not statistically significant (p = 0.28). Conclusions The choroid in MacTel type 2 patients was significantly thickened as compared to controls. SFCT may vary as the structural changes worsen over time.
关键词： Macular telangiectasia type 2,Swept source optical coherence tomography,Subfoveal choroidal thickness,Enhanced depth imaging
更新于2025-09-23 15:22:29
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Reproducibility and reliability of retinal and optic disc measurements obtained with swept-source optical coherence tomography in a healthy population
摘要： Purpose To analyze the reproducibility of macular and peripapillary thickness measurements, and optic nerve morphometric data obtained with Triton Optical coherence tomography (OCT) in a healthy population. Study design Observational cross sectional study. Material and methods A total of 108 eyes underwent evaluation using the Triton Swept Source-OCT. A wide protocol was used and measurements in each eye were repeated three times. Morphometric data of the optic nerve head, full macular thickness, ganglion cell layer (GCL) and retinal nerve fiber layer thickness (RNFL) were analyzed. For each parameter, the coefficient of variation (COV) and the intra-class (ICC) correlation values were calculated. Results Measurements were highly reproducible for all morphometric measurements of the optic disc, with a mean COV of 6.36%. Macular full thickness showed good COV and ICC coefficients, with a mean COV value of 1.00%. Macular GCL thickness showed a mean COV value of 3.06%, and ICC higher than 0.787. Peripapillary RNFL thickness showed good COV and ICC coefficients, with a mean COV value of 8.31% and ICC higher than 0.684. The inferotemporal sector showed the lowest ICC (0.685). Conclusions Triton OCT presents good reproducibility values in measurements corresponding to retinal parameters, with macular measurements showing the highest reproducibility rates. Peripapillary RNFL measurements should be evaluated with caution.
关键词： Reproducibility,Optical coherence tomography,Coefficient of variation,Swept source
更新于2025-09-23 15:22:29
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Choroidal imaging biomarkers
摘要： The choroid is the vascular coat of the eye,and its role has been studied in multiple chorioretinal disorders. The recent advancements in choroidal imaging techniques including enhanced depth imaging optical coherence tomography (EDI-OCT), swept source (SS-OCT), enface OCT and OCT angiography have facilitated an in-depth analysis of choroid. The gradual shift from manual to automated segmentation and binarization methods have led to precise and reproducible measurements of choroidal parameters. These qualitative and quantitative parameters, called choroidal imaging biomarkers, have evolved over the past decade from a simple linear subfoveal choroidal thickness to more complex 3 dimensional (3-D) choroidal reconstruction thus widening the spectrum encompassing multiple parameters. These biomarkers have provided a better understanding of the pathogenesis, are helpful in diagnostic dilemmas, and in future may also help to devise treatment options. The lack of normative data, absence of standardized parameters and limitations of the imaging techniques, however, have led to ambiguity and difficulty in the interpretation of these variables. We attempt to address these lacunae in the literature and provide a basic understanding of the choroid in both health and disease using these choroidal biomarkers.
关键词： Optical coherence tomography angiography (OCTA),En-face OCT,Swept source optical coherence tomography (SS-OCT),Choroidal thickness,Choroidal vascularity index (CVI),Choroidal imaging biomarkers,Choroidal volume
更新于2025-09-23 15:21:21
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Cataract quantification using swept-source optical coherence tomography
摘要： To develop and evaluate a cataract quantification method using a swept-source optical coherence tomography (SS-OCT) device (IOLMaster 700).
关键词： SS-OCT,swept-source optical coherence tomography,IOLMaster 700,LOCS II,cataract quantification
更新于2025-09-23 15:21:01
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Swept-Source Optical Coherence Tomography Angiography in Central Serous Chorioretinopathy
摘要： Purpose: This article aims to evaluate the appearance of central serous chorioretinopathy (CSC) with swept-source optical coherence tomography angiography (SS-OCTA), to discuss whether localization of the leakage spot seen on fluorescein angiography (FA) corresponds to any recognizable spot on SS-OCTA, and to provide subsequent diagnosis of choroidal neovascularization (CNV) in the course of CSC. Methods: A prospective interventional case series was conducted in a private outpatient office on 30 eyes of 27 patients. In addition to ophthalmic examination, FA, spectral-domain OCT, SS-OCT and SS-OCTA were performed at least once. If laser photocoagulation or anti-vascular endothelial growth factor (anti-VEGF) injection was administered, then all examinations were repeated afterward. Following SS-OCTA, morphology features of CSC were analyzed: localization of the leakage spot, presence of feeder vessels, and presence of CNV. Changes after treatment were recorded. Results: In 26 of 30 cases the leakage site on FA corresponded to a highly hyporeflective site on SS-OCTA. In 7 of these cases laser was successfully administered. In 20/30 eyes we additionally observed thickened vessels at the level of choriocapillaris in close proximity to the most hyporeflective spot. CNV was observed in 4 cases. The leakage spot is the most hyporeflective spot on SS-OCTA localized at the level of choriocapillaris. Additionally, choroidal feeder vessels might be visualized at the level of choriocapillaris in 66% of cases. In 4 eyes, CNV in the course of CSC was noted. Conclusions: In CSC, SS-OCTA is a valuable diagnostic tool and its results complement FA. It might add to the treatment process, especially regarding the need to start and to monitor anti-VEGF injections. Anti-VEGF treatment results in fading but not in complete disappearance of CNV in the course of CSC.
关键词： central serous chorioretinopathy,swept-source OCT angiography,anti-VEGF,laser
更新于2025-09-23 15:21:01
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Bifurcation structure of a swept-source laser
摘要： We numerically analyze a delay differential equation model of a short-cavity semiconductor laser with an intracavity frequency-swept filter and reveal a complex bifurcation structure responsible for the asymmetry of the output characteristics of this laser. We show that depending on the direction of the frequency sweep of a narrow-band filter, there exist two bursting cycles determined by different parts of a continuous-wave solutions branch.
关键词： delay differential equation,frequency-swept filter,swept-source laser,semiconductor laser,bifurcation structure
更新于2025-09-19 17:13:59