1. All Articles

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    1. Vascular and Structural Alterations of the Choroid Evaluated by Optical Coherence Tomography Angiography and Enhanced-Depth Imaging Optical Coherence Tomography in Eyes with Reticular Pseudodrusen and Soft Drusen

      Vascular and Structural Alterations of the Choroid Evaluated by Optical Coherence Tomography Angiography and Enhanced-Depth Imaging Optical Coherence Tomography in Eyes with Reticular Pseudodrusen and Soft Drusen

      Background To assess the vascularity of choriocapillaris and structural choroidal differences in eyes with reticular pseudodrusen (RPD) and soft drusen. Methods 21 eyes with RPD (group 1), 17 eyes with soft drusen (group 2), and 19 eyes as a control group (group 3) were included in this study. Choriocapillaris vascular density and flow area were measured by optical coherence tomography angiography. Total choroidal area, luminal area, stromal area, and lumen/stroma ratios were measured on optical coherence tomography B-scans converted to binary images. Results Mean choriocapillaris vascular density was higher in group 3 than other groups (group 1 vs 3 ...

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    2. Total venous nature of retinal deep capillary plexus inferred by continuity of prominent middle limiting membrane sign in optical coherence tomography

      Total venous nature of retinal deep capillary plexus inferred by continuity of prominent middle limiting membrane sign in optical coherence tomography

      This study aimed to theoretically identify the vascular nature of the deep capillary plexus (DCP) by examining patients presenting with both paracentral acute middle maculopathy (PAMM) and prominent middle limiting membrane (p-MLM) sign and p-MLM sign alone in spectral-domain optical coherence tomography (SD-OCT). A retrospective review of the medical records of patients with retinal vein or artery occlusion from two tertiary medical centers was performed. Consecutive patients with a clinical diagnosis of all categories of retinal artery occlusion (RAO) and retinal vein occlusion (RVO) (branch or central and ischemic or non-ischemic) who had undergone SD-OCT imaging from January 2015 to ...

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    3. Evaluating Onychomycosis Outcomes 2 Months into an 11-month-long Efinaconazole Regimen: The Role of Optical Coherence Tomography

      Evaluating Onychomycosis Outcomes 2 Months into an 11-month-long Efinaconazole Regimen: The Role of Optical Coherence Tomography

      Background. Onychomycosis affects 43 million people in the United States and Europe. Topical therapies can be effective but require lengthy and costly regimens without an established method for predicting the treatment outcome. Objective. We studied the role of optical coherence tomography (OCT), a noninvasive imaging device approved by the United States Food and Drug Administration, in evaluating onychomycosis treatment outcomes. Methods. This investigator-initiated prospective clinical study recruited subjects from two urban medical centers. A total of 34 subjects with mild-to-moderate onychomycosis, confirmed using periodic acid-Schiff (PAS) staining, were treated with topical efinaconazole for 48 weeks, at which time a final ...

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    4. Accuracy of Common Motion Estimators in Wave-Based Optical Coherence Elastography

      Accuracy of Common Motion Estimators in Wave-Based  Optical Coherence Elastography

      Abstract. Motion estimators are commonly used in shear wave optical coherence elastography to compute small displacements. This work focuses on comparing three motion estimators: Kasai, Loupas, and the vector method. Our results show that the vector method is superi or in low - SNR, low - amplitude situations for group velocity calculation and profile reconstruction . © 202 1 Journal of Biomedical Photonics & Engineering.

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    5. Quantitative evaluation of the dynamic activity of HeLa cells in different viability states using dynamic full-field optical coherence microscopy

      Quantitative evaluation of the dynamic activity of HeLa cells in different viability states using dynamic full-field optical coherence microscopy

      Dynamic full-field optical coherence microscopy (DFFOCM) was used to characterize the intracellular dynamic activities and cytoskeleton of HeLa cells in different viability states. HeLa cell samples were continuously monitored for 24 hours and compared with histological examination to confirm the cell viability states. The averaged mean frequency and magnitude observed in healthy cells were 4.79±0.5 Hz and 2.44±1.06, respectively. In dead cells, the averaged mean frequency was shifted to 8.57±0.71 Hz, whereas the magnitude was significantly decreased to 0.53±0.25. This cell dynamic activity analysis using DFFOCM is expected ...

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    6. A New Method for Automating the Diagnostic Analysis of Human Fundus Images Obtained Using Optical Coherent Tomography Angiography

      A New Method for Automating the Diagnostic Analysis of Human Fundus Images Obtained Using Optical Coherent Tomography Angiography

      This article presents the results of the joint work of image analysis specialists and ophthalmologists on the problem of analyzing images obtained by optical coherence tomography (angiography). A descriptive algorithmic scheme for analyzing images obtained using optical coherence tomography angiography was constructed to automate detection of pathological changes in the morphometric characteristics of the fundus. The algorithmic scheme is based on the image processing, analysis, and recognition methods. A feature space has been developed that makes it possible to identify pathological changes in the structure of the vascular plexuses of the human retina. It was possible to achieve high-accuracy classification ...

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    7. Quantifying Retinal Microvascular Morphology in Schizophrenia Using Swept-Source Optical Coherence Tomography Angiography

      Quantifying Retinal Microvascular Morphology in Schizophrenia Using Swept-Source Optical Coherence Tomography Angiography

      Background: Retinovascular changes are reported on fundus imaging in schizophrenia (SZ). This is the first study to use swept-source optical coherence tomography angiography (OCT-A) to comprehensively examine retinal microvascular changes in SZ. Methods: This study included 30 patients with SZ/schizoaffective disorder (8 early and 15 chronic) and 22 healthy controls (HCs). All assessments were performed at Beth Israel Deaconess Medical Center and Massachusetts Eye and Ear. All participants underwent swept-source OCT-A of right (oculus dextrus [OD]) and left (oculus sinister [OS]) eye, clinical, and cognitive assessments. Macular OCT-A images (6 × 6 mm) were collected with the DRI Topcon Triton ...

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    8. In vivo examination of healthy human skin after short-time treatment with moisturizers using confocal Raman spectroscopy and optical coherence tomography: Preliminary observations

      In vivo examination of healthy human skin after short-time treatment with moisturizers using confocal Raman spectroscopy and optical coherence tomography: Preliminary observations

      Skin is our barrier against environmental damage. Moisturizers are widely used to increase hydration and barrier integrity of the skin; however, there are contrasting observations on their in vivo effects in real-life settings. In cosmetic studies, corneometers and tewameters are traditionally used to assess skin hydration. In this study, two novel noninvasive diagnostic techniques, optical coherence tomography (OCT) and confocal Raman spectroscopy, were used to analyze stratum corneum and epidermal thickness (ET), water content, blood flow in function of depth, skin roughness, attenuation coefficient, natural moisturizing factor, ceramides and free fatty acids, cholesterol, urea, and lactates in 20 female subjects ...

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    9. Human Foveal Cone and Müller Cells Examined by Adaptive Optics Optical Coherence Tomography

      Human Foveal Cone and Müller Cells Examined by Adaptive Optics Optical Coherence Tomography

      Purpose: The purpose of this study was to image and investigate the foveal microstructure of human cone and Müller cells using adaptive optics-optical coherence tomography. Methods: Six healthy subjects underwent the prototype adaptive optics-optical coherence tomography imaging, which allowed an axial resolution of 3.4 µm and a transverse resolution of approximately 3 µm. The morphological features of the individual retinal cells observed in the foveola were qualitatively and quantitatively evaluated. Results: In the six healthy subjects, the image B-scans showed hyper-reflective dots that were densely packed in the outer nuclear layer. The mean number, diameter, and density of ...

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    10. Comment on Real-Time In Vivo Assessment of Retinal Reattachment in Humans Using Swept-Source Optical Coherence Tomography

      Comment on Real-Time In Vivo Assessment of Retinal Reattachment in Humans Using Swept-Source Optical Coherence Tomography

      We read with interest the manuscript by Bansal and associates 1 regarding optical coherence tomography (OCT) to assess retinal reattachment following successful pneumatic retinopexy (PnR). The authors propose that retinal reattachment occurs through 5 specific stages: approach of the neurosensory retina towards the retinal pigment epithelium (RPE, stage 1), improvement of outer retinal corrugations (stage 2), contact of the neurosensory retina to the RPE (stage 3), deturgescence of the photoreceptors (stage 4) and recovery of photoreceptor integrity (stage 5). An incomplete resolution of outer retinal corrugations before retinal reattachment may lead, according to the authors, to the formation of outer ...

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    11. What explorations involve the fundamental workings of the inner ear?– Webinar October 6th, 2021

      What explorations involve the fundamental workings of the inner ear?– Webinar October 6th, 2021

      This free, live event will take place on October 6 th, 10 EDT (4 PM CET) and will include an interactive Q&A session. For information and to register please visit this link. After the event a recorded version will be available at www.thorlabs.com/webinars . Abstract: Drs. Elizabeth Olson and Elliott Strimbu from Columbia University will highlight Phase Sensitive Spectral Domain Optical Coherence Tomography as it relates to nanoscale vibrometry. They will cover in detail the performance parameters of a Thorlabs Telesto for nanoscale displacement measurements in the cochlea and leverage their years of experience in the field ...

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    12. Quantification of volumetric morphometry and optical property in the cortex of human cerebellum at micrometer resolution

      Quantification of volumetric morphometry and optical property in the cortex of human cerebellum at micrometer resolution

      The surface of the human cerebellar cortex is much more tightly folded than the cerebral cortex. Volumetric analysis of cerebellar morphometry in magnetic resonance imaging studies suffers from insufficient resolution, and therefore has had limited impact on disease assessment. Automatic serial polarization-sensitive optical coherence tomography (as-PSOCT) is an emerging technique that offers the advantages of microscopic resolution and volumetric reconstruction of large-scale samples. In this study, we reconstructed multiple cubic centimeters of ex vivo human cerebellum tissue using as-PSOCT. The morphometric and optical properties of the cerebellar cortex across five subjects were quantified. While the molecular and granular layers exhibited ...

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    13. Choriocapillaris Flow Deficits in Normal Chinese Imaged by Swept-Source Optical Coherence Tomographic Angiography

      Choriocapillaris Flow Deficits in Normal Chinese Imaged by Swept-Source Optical Coherence Tomographic Angiography

      Purpose To evaluate the ocular and systemic determinants of the choriocapillaris flow deficits percentage (CC FD%) in normal eyes. Design Observational cross-sectional study. Methods Healthy Chinese participants without ocular or systemic diseases underwent detailed ophthalmic evaluations, including swept-source optical coherence tomography angiography (SS-OCTA) with 6 × 6 mm macular choriocapillaris images. The CC FD% was assessed in circular regions with diameters of 1.0 and 5.0 mm, rings with 1.0–2.5-mm and 2.5–5.0-mm diameters. Results The study included 830 individuals (mean age: 58.66±8.75 years). CC FD% (mean: 22.05%±1.13%) was ...

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    14. Identification of Sex and Age from Macular Optical Coherence Tomography and Feature Analysis Using Deep Learning

      Identification of Sex and Age from Macular Optical Coherence Tomography and Feature Analysis Using Deep Learning

      Purpose To develop deep learning models for identification of sex and age from macular optical coherence tomography (OCT), and to analyze the features for differentiation of sex and age. Design Algorithm development using database of macular OCT. Setting One eye center in Taiwan. Study Population 6147 sets of macular optical coherence tomography (OCT) images from the healthy eyes of 3134 persons. Main Outcome Measures Deep learning based algorithms were used to develop models for identification of sex and age, and 10-fold cross-validation was applied. Gradient-weighted class activation mapping (Grad-CAM) was used for feature analysis. Results The accuracy for sex prediction ...

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    15. Estimation of scleral mechanical properties from air-puff optical coherence tomography

      Estimation of scleral mechanical properties from air-puff optical coherence tomography

      We introduce a method to estimate the biomechanical properties of the porcine sclera in intact eye globes ex vivo , using optical coherence tomography that is coupled with an air-puff excitation source, and inverse optimization techniques based on finite element modeling. Air-puff induced tissue deformation was determined at seven different locations on the ocular globe, and the maximum apex deformation, the deformation velocity, and the arc-length during deformation were quantified. In the sclera, the experimental maximum deformation amplitude and the corresponding arc length were dependent on the location of air-puff excitation. The normalized temporal deformation profile of the sclera was distinct ...

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    16. A Quantitative Model for Optical Coherence Tomography

      A Quantitative Model for Optical Coherence Tomography

      Optical coherence tomography (OCT) is a widely used imaging technique in the micrometer regime, which gained accelerating interest in medical imaging in the last twenty years. In up-to-date OCT literature [5, 6] certain simplifying assumptions are made for the reconstructions, but for many applications a more realistic description of the OCT imaging process is of interest. In mathematical models, for example, the incident angle of light onto the sample is usually neglected or a plane wave description for the light-sample interaction in OCT is used, which ignores almost completely the occurring effects within an OCT measurement process. In this article ...

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    17. Comparison of inner macular thickness and superficial macular capillary vessel density acquired using classic and high-definition optical coherence tomography angiography scans

      Comparison of inner macular thickness and superficial macular capillary vessel density acquired using classic and high-definition optical coherence tomography angiography scans

      Background: In ophthalmology, thickness and vessel density (VD) measurements for the 6 x 6 mm inner macular retinal area have received increasing attention in glaucomatous progression research. For this area, the Angiovue optical coherence tomography system introduced a 304 x 304 A/B scans function (classic Angio Retina scan) in 2014, and a 400 x 400 A/B scans function (high-definition [HD] Angio Retina scan) in 2017. These scan types cannot be used in combination for the software provided for progression analysis. Purpose: Since losing data for 3 years may negatively influence progression analysis, we investigated whether clinically significant differences ...

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    18. Neuro-ophthalmological diseases masquerading as glaucoma in the Optical Coherence Tomography era: A case series

      Neuro-ophthalmological diseases masquerading as glaucoma in the Optical Coherence Tomography  era: A case series

      Background: Intracranial compressive lesions masquerading as glaucomatous optic neuropathy have been previous ly described in the literature but remain a diagnosis challenge for trained physicians. We present a case series of patients referred to our center as glaucoma suspects or diagnosed with glaucoma, looking for a second opinion. We aim to highlight how clini cal clues and Optical Coherence Tomography (OCT) findings helped identify a condition different from glaucoma. Case presentation: A 55 - year - old male presented a painless decrease in his visual acuity and elevated intraocular pressure of both eyes. His OCT revealed Ganglion Cell Layer thinning, and Humphrey ...

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    19. Synthesis and Research of Nanocompositions of Oxide Materials Based on Titanium Dioxide for use as Contrast Agents in Optical Coherence Tomography

      Synthesis and Research of Nanocompositions of  Oxide Materials Based on Titanium Dioxide for use  as Contrast Agents in Optical Coherence  Tomography

      n this paper, the contrasting properties of titanium dioxide nanoparticles in various compositions were considered. In the course of the work, methods for the synthesis of oxide materials SiO 2 - TiO 2 , SiO 2 - ZrO 2 , TiO 2 - ZrO 2 and SiO 2 - TiO 2 - ZrO 2 were developed; the microstructure of oxide materials SiO 2 - TiO 2 , SiO 2 - ZrO 2 , TiO 2 - ZrO 2 and SiO 2 - TiO 2 - ZrO 2 was studied; the stability of oxide materials SiO 2 - TiO 2 , SiO 2 - ZrO 2 , TiO 2 - ZrO 2 and SiO 2 - TiO 2 - ZrO 2 was ...

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    20. Uncertainty-guided self-ensembling model for semi-supervised segmentation of multiclass retinal fluid in optical coherence tomography images

      Uncertainty-guided self-ensembling model for semi-supervised segmentation of multiclass retinal fluid in optical coherence tomography images

      Macular edema is the accumulation of fluid leakage from retinal capillaries. Optical coherence tomography (OCT) images can show changes in the retinal tissue caused by ophthalmological diseases, such as fluid accumulation. Therefore, the segmentation of retinal fluid is important. Some methods based on image processing and machine learning often require large amounts of labeled data and rich domain knowledge. This study proposes a self-ensembling semi-supervised model based on uncertainty guidance, namely, UGNet. The model is trained end-to-end with a few labeled data and plenty of unlabeled data, and contains a teacher model and a student model with the same architecture ...

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    21. Deep-learning based retinal fluid segmentation in optical coherence tomography images using a cascade of ENets

      Deep-learning based retinal fluid segmentation in optical coherence tomography images using a cascade of ENets

      Optical coherence tomography (OCT) is a non-invasive, painless and reproducible examination which allows ophthalmologists to visualize retinal layers. This imaging modality is useful to detect diseases such as diabetic macular edema (DME) or age related macular degeneration (AMD), which are associated with fluid accumulations. In this paper, a cascade of deep convolutional neural networks is proposed using ENets for the segmentation of fluid accumulations in OCT B-Scans. After denoising the B-Scans, a first ENet extracts the region of interest (ROI) between the inner limiting membrane (ILM) and the Bruch's membrane (BM), whereas the second ENet segments the fluid in ...

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    22. Standardization of Optical Coherence Tomography Angiography Imaging Biomarkers in Diabetic Retinal Disease

      Standardization of Optical Coherence  Tomography Angiography Imaging  Biomarkers in Diabetic Retinal Disease

      Optical coherence tomography Angiography (OCT-A) represents a revolution in the noninvasive evaluation of retinal and choroidal circulation especially in detecting early clinical signs of diabetic retinal disease (DRD). With appropriate use, OCT-A characteristics and measurements have the potential to become new imaging biomarkers in managing and treating DRD. Major challenges include (a) provision of standardized outputs from different OCT-A instruments providing standardized terminology to correctly interpret data; (b) the presence of artifacts; (c) the absence of standardized grading or interpretation method in the evaluation of DRD, similar to that already established in fundus photography; and (d) establishing how OCT-A might ...

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    23. In-situ observation of evolution of internal structure of alumina during sintering by swept-source OCT

      In-situ observation of evolution of internal structure of alumina during sintering by swept-source OCT

      In-situ observation of sintering of ceramics is important to understand the sintering behavior, including the development of internal structures, and to fabricate ceramics with superior properties. However, there has been no studies thus far on high-speed in-situ observation of the internal structure of green and sintered bodies at high temperatures with μm-scale resolution. Here, we applied swept-source optical coherence tomography (OCT) to observe the evolution of the internal structure in Al 2 O 3 green bodies during sintering. In-situ OCT observations revealed that internal structure changes during sintering, such as the development of density distribution and growth of coarser pores ...

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