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A direct scattering optical coherence tomography forward model was developed to simulate A-scans for both idealized and real light sources on an arbitrary given sample structure. Previous models neglected absorption, scattering, and multiple reflections at interfacial layers, and so two extended models were developed to investigate the impact of these processes. The first model uses the Beer-Lambert law to incorporate both absorption and scattering optical processes, and the second model uses a recursive form to model multiple reflections. These models were tested on a structure representative of a multilayered skin sample. The results show that the absorption and scattering ...

One or more devices, systems, methods and storage mediums for performing continuously, full range optical coherence tomography (OCT) without losing A-lines are provided. Examples of such applications include imaging, evaluating and diagnosing biological objects, such as, but not limited to, for cardio and/or ophthalmic applications, and being obtained via one or more optical instruments, such as, but not limited to, optical probes (e.g., common path probes), catheters, endoscopes, phase shift units (e.g., galvanometer scanner) and bench top systems. Preferably, the OCT devices, systems methods and storage mediums include or involve a phase shift device including at least ...

Methods and apparatus are presented for obtaining high-resolution 3-D images of a sample over a range of wavelengths, optionally with polarisation-sensitive detection. In preferred embodiments a spectral domain OCT apparatus is used to sample the complex field of light reflected or scattered from a sample, providing full range imaging. In certain embodiments structured illumination is utilised to provide enhanced lateral resolution. In certain embodiments the resolution or depth of field of images is enhanced by digital refocusing or digital correction of aberrations in the sample. Individual sample volumes are imaged using single shot techniques, and larger volumes can be imaged ...

Purpose: To measure marginal reflex distance-1 (MRD-1) values in normal subjects and patients with blepharoptosis using second-generation swept-source anterior segment optical coherence tomography (AS-OCT) and to evaluate the usefulness of this measurement method. Materials and Methods: MRD-1 values were measured using AS-OCT in 80 eyes of 40 normal subjects (16 men and 24 women) aged 20- 59 years with no neurological or endocrinological disorders, and the measured values were compared between four age groups comprising 20 eyes of 10 subjects each in their 20s, 30s, 40s, and 50s. The Volk Eye Check system was simultaneously used to measure MRD-1 in ...

Purpose: To assess the utility of microscope-integrated intraoperative optical coherence tomography (Mi-OCT) for performing Descemet membrane endothelial keratoplasty (DMEK) in corneas with poor visualization. Methods: It is a prospective interventional case series that included 25 consecutive cases of corneal decompensation with poor visualization that underwent Mi-OCT-guided DMEK at a tertiary eye care centre. The main outcome measures were graft attachment on day 3 and requirement for re-bubbling. Results: The etiology for corneal decompensation was pseudophakic bullous keratopathy (n=17), Fuchs endothelial corneal dystrophy (n=4), failed graft (n=2), iridocorneal endothelial syndrome (n=1) and failed Descemet stripping automated endothelial ...

An OCI medical device includes a coherent light source, a light sensor, a first processing unit adapted to calculate OCI Data from the light sensor, a control unit which allows taking or loading of at least one Reference OCI Value, a second processing unit adapted to calculate the Intra-Individual Relative Assessment of the OCI Data of an Imaging Zone and the at least one OCI Reference Value, and display means adapted to show at least one Relative OCI Value. Uses and a method for assessing the blood flow of a body region use OCI imaging and include an Intra-Individual Relative ...

The present disclosure describes systems and method for generating surgical maps that provide a surgeon with information regarding the placement of features of interest. More particularly, the system is configured to display optical coherence tomography (OCT) images to a medical professional. The medical professional can select anatomical features, biomarkers, and other features of interest within each of the OCT images. The system can then translate the location of the features of interest within the OCT images to an en face image to generate a map of the features that the medical professional can use for surgical guidance.

Optical tomographic cross-sectional images of biological samples were made possible by interferometric imaging techniques such as Optical Coherence Tomography (OCT) [1, 2, 3]. Owing to its unprecedented view of the sample, OCT has become a gold standard, namely for human retinal imaging in the clinical environment. In this Letter, we present Optical Incoherence Tomography (OIT): a completely digital method extending the possibility to generate tomographic retinal cross-sections to non-interferometric imaging systems such as en-face AO-ophthalmoscopes [4, 5]. We demonstrate that OIT can be applied to different imaging modalities using back-scattered and multiply-scattered light including systems without inherent optical sectioning. We ...

Purpose The aim of the current study is to demonstrate the potential of rare earth (RE) based upconversion nanoparticles (UCNPs) as molecular probing agents for non-invasive depth-resolved bioimaging technique, swept-source optical coherence tomography (SSOCT). Methods The Na + doped La 2 O 3 :Er 3+ /Yb 3+ UCNPs were synthesized using a solution combustion route with characterization for emission spectra and morphological study. A custom made SSOCT system was also incorporated for tissue imaging with an A-scan rate of 100 kHz/s, the central wavelength of 1060 nm, an axial and lateral resolution of ~?4.5 ?m and ~?13 ?m in ...

Background To evaluate retinal and choriocapillaris (CC) vessel density in macular region in patients affected by adult-onset foveomacular vitelliform dystrophy (AOFVD) using optical coherence tomography angiography (OCTA) Methods A total forty-four right eyes of 44 AOFVD patients (20 females, 24 males, mean age 69.17???11.57 years) divided in 3 stages (vitelliform, pseudohypopyon and vitelliruptive) and 60 normal right eyes of 60 controls (20 females, 40 males, mean age 66.04???6.40 years) were included in this prospective study. We evaluated the vessel density of superficial capillary plexus (SCP), deep capillary plexus (DCP) and CC in different macular ...

To solve the phase unwrapping problem for phase images in Fourier domain Doppler optical coherence tomography (DOCT), we propose a deep learning-based residual en-decoder network (REDN) method. In our approach, we reformulate the definition for obtaining the true phase as obtaining an integer multiple of 2? at each pixel by semantic segmentation. The proposed REDN architecture can provide recognition performance with pixel-level accuracy. To address the lack of phase images that are noise and wrapping free from DOCT systems for training, we used simulated images synthesized with DOCT phase image background noise features. An evaluation study on simulated images, DOCT ...

Purpose To evaluate retinal vascular parameters by optical coherence tomography angiography (OCT-A) in iron deficiency anemia (IDA). Methods Thirty-two patients with IDA (study group) and 30 healthy children (control group) were enrolled in the study. All subjects underwent a complete ocular examination. OCT-A scans were performed in a 6???6 mm area centered on the macula. Foveal avascular zone (FAZ), non-flow area (NFA), FAZ perimeter (PERIM), acircularity index (AI) of FAZ, and foveal density (FD) were measured in the superficial capillary plexus (SCP) and deep capillary plexus (DCP). SCP and DCP were also scanned centered on the optic disk. Hemoglobin ...

(1) Aim: Contrasting results have been published on the effect of dark chocolate on visual function. The aim of this study was to evaluate retinal and choriocapillaris perfusion, using optical coherence tomography angiography (OCT-A), and visual function in healthy subjects following dark chocolate ingestion. (2) Methods: This prospective randomized study was carried out on 18 healthy young subjects at the St. Andrea Hospital, Sapienza, University of Rome. Visual acuity assessment and a complete ophthalmologic examination were carried out at baseline. In session one, each subject was randomized to eat either a 100 g dark chocolate bar or a 100 g ...

Purpose To determine the intensity of corneal pigmented arc in orthokeratology (ortho-k)-treated children and its correlation with wide epithelial thickness map (ETM) obtained through anterior segment optical coherent tomography (AS-OCT). Methods This retrospective case series reviews medical records of children who received ortho-k treatment for myopia control. Intensity of ortho-k-associated pigmented arc after wearing ortho-k lens more than 12 months and its correlation with each sector/zone of wide ETM obtained by AS-OCT was explored. Pigmented arcs were further divided into apparent and unapparent groups, and the clinical differences between groups were determined. Results This study included 57 eyes ...

Purpose Optical coherence tomography angiography (OCTA) was performed on patients with juvenile-onset type 1 diabetes (T1DM) but with no diabetic retinopathy to measure the foveal avascular zone (FAZ) area. Study Design Retrospective single-facility study Methods Twenty-nine patients (58 eyes) with juvenile-onset T1DM were studied. Images (3 mm x 3 mm cube centered on the fovea) were acquired using an OCTA device. Age at examination was 16.1 ? 8.7 years; onset age was 6.4 ? 3.5 years; duration of diabetes was 9.7 ? 8.3 years. Twenty-four age-matched healthy individuals were studied as controls. Results FAZ area was significantly ...

Laser ablation can be an effective modality for treatment, but it is complicated to apply continuous-wave (CW) light sources for laser ablation because of the unpredictable photothermal damage. In this study, an integrated theranostic system combining a low-cost CW laser diode with optical coherence tomography (OCT)/angiography (OCTA) was utilized for the in vivo ablation of tumor tissues. To examine the effect of laser exposure on tissue scattering characteristics, the OCT backscattering intensities of non-ablated and ablated tissues were analyzed, and the effect on the skin microvasculature produced by laser ablation was quantitatively evaluated. Moreover, the integrated system and the ...

Background To evaluate the effect of orthokeratology on precision of measurements in children using a new swept-source optical coherence tomography (SS-OCT) optical biometer (OA-2000), and agreement between its measurements and those provided by the commonly used IOLMaster based on partial coherence interferometry (PCI). Methods This study recruited fifty-one eyes of 51 normal children (8-16?years). An operator took measurements with the two biometers. Then, a second operator took measurements with the SS-OCT biometer. After orthokeratology was performed for one month, the same operators repeated the same procedures. Axial length (AL), mean keratometry (Km) at 2.5 mm and 3 ...

Purpose : To evaluate the relationship between visual acuity, visual field and spectral domain optical coherence tomography (OCT) parameters, including retinal nerve fiber layer (RNFL), ganglion cell-internal plexiform layer (GC-IPL) thicknesses, and optic nerve head parameters in patients with severe glaucoma. Material and Methods : Patients with the diagnosis of severe glaucoma were recruited from the data gathered at our glaucoma department. A detailed ophthalmic examination was performed using the Standard Automated Perimetry (the 30-2 SITA standard program was used for VF testing). Cirrus EDI-OCT was used for peripapillary RNFL and GC-IPL thickness measurements. Optic nerve head parameters, including mean cup-to-disc ...

Recent developments and commercial availability of low-noise and bright infrared (IR) supercontinuum sources initiated intensive applied research in the last few years. Covering a significant part of near- and mid-infrared spectral ranges, supercontinuum radiation opened up unique possibilities and alternatives for the well-established imaging technique of optical coherence tomography (OCT). In this contribution, we demonstrate the development, performance, and maturity of a cost-efficient dual-band Fourier-domain IR OCT system (2 ?m and 4 ?m central wavelengths). The proposed OCT setup is elegantly employing a single supercontinuum source and a pyroelectric linear array. We discuss adapted application-oriented approaches to signal acquisition and ...

Line-field confocal optical coherence tomography (LC-OCT) is an imaging technique in which A-scans are acquired in parallel through line illumination with a broadband laser and line detection with a line-scan camera. B-scan imaging at high spatial resolution is achieved by dynamic focusing in a Linnik interferometer. This paper presents an LC-OCT device based on a custom-designed Mirau interferometer that offers similar spatial resolution and detection sensitivity. The device has the advantage of being more compact and lighter. In vivo imaging of human skin with a resolution of 1.3 ?m ? 1.1 ?m (lateral ? axial) is demonstrated over a field ...

Purpose To describe the nystagmus characteristics of subjects with molecularly confirmed CNGB3 -associated achromatopsia and report the spectral domain optical coherence tomography (SD-OCT) findings in these individuals. Methods Adults and children with CNGB3 -achromatopsia underwent visual acuity testing, ocular motility assessments, video nystagmography, and SD-OCT imaging. Qualitative assessment of foveal structure was performed by grading SD-OCT images into one of five categories. Results A total of 18 subjects (11 adults) were included. The majority demonstrated a phoria, with manifest strabismus present in only 3 subjects. The predominant nystagmus waveform within the cohort was pure pendular. Nine individuals demonstrated a mixture ...

Purpose To estimate the central 10-degree visual field of glaucoma patients using en-face images obtained by optical coherence tomography (OCT), and to examine its usefulness. Patients and methods Thirty-eight eyes of 38 patients with primary open angle glaucoma were examined. En-face images were obtained by swept-source OCT (SS-OCT). Nerve fiber bundles (NFBs) on en-face images at points corresponding to Humphrey Field Analyzer (HFA) 10-2 locations were identified with retinal ganglion cell displacement. Estimated visual fields were created based on the presence/absence of NFBs and compared to actual HFA10-2 data. ? coefficients were calculated between probability plots of visual fields ...

The Skin Pathology assessment with Optical Technologies (SPOT) study aims to assess the feasibility of recently developed light-based skin imaging tools such as Optical Coherence Tomography (OCT) for the study of eczema (dermatitis [AD]). Tools such as OCT have enabled us to see beneath the skin surface, allowing us to see changes in our skin which are hidden and impossible to assess by eye, simply by shining harmless light into the skin. The investigators want to understand what these changes represent in the broader context of eczema. To do this, the investigators would like to recruit 60 volunteers who have ...

Optical tomographic cross-sectional images of biological samples were made possible by interferometric imaging techniques such as Optical Coherence Tomography (OCT) [1, 2, 3]. Owing to its unprecedented view of the sample, OCT has become a gold standard, namely for human retinal imaging in the clinical environment. In this Letter, we present Optical Incoherence Tomography (OIT): a completely digital method extending the possibility to generate tomographic retinal cross-sections to non-interferometric imaging systems such as en-face AO-ophthalmoscopes [4, 5]. We demonstrate that OIT can be applied to different imaging modalities using back-scattered and multiply-scattered light including systems without inherent optical sectioning. We ...

Purpose The aim of the current study is to demonstrate the potential of rare earth (RE) based upconversion nanoparticles (UCNPs) as molecular probing agents for non-invasive depth-resolved bioimaging technique, swept-source optical coherence tomography (SSOCT). Methods The Na + doped La 2 O 3 :Er 3+ /Yb 3+ UCNPs were synthesized using a solution combustion route with characterization for emission spectra and morphological study. A custom made SSOCT system was also incorporated for tissue imaging with an A-scan rate of 100 kHz/s, the central wavelength of 1060 nm, an axial and lateral resolution of ~?4.5 ?m and ~?13 ?m in ...

Background To evaluate retinal and choriocapillaris (CC) vessel density in macular region in patients affected by adult-onset foveomacular vitelliform dystrophy (AOFVD) using optical coherence tomography angiography (OCTA) Methods A total forty-four right eyes of 44 AOFVD patients (20 females, 24 males, mean age 69.17???11.57 years) divided in 3 stages (vitelliform, pseudohypopyon and vitelliruptive) and 60 normal right eyes of 60 controls (20 females, 40 males, mean age 66.04???6.40 years) were included in this prospective study. We evaluated the vessel density of superficial capillary plexus (SCP), deep capillary plexus (DCP) and CC in different macular ...

To solve the phase unwrapping problem for phase images in Fourier domain Doppler optical coherence tomography (DOCT), we propose a deep learning-based residual en-decoder network (REDN) method. In our approach, we reformulate the definition for obtaining the true phase as obtaining an integer multiple of 2? at each pixel by semantic segmentation. The proposed REDN architecture can provide recognition performance with pixel-level accuracy. To address the lack of phase images that are noise and wrapping free from DOCT systems for training, we used simulated images synthesized with DOCT phase image background noise features. An evaluation study on simulated images, DOCT ...

Purpose To evaluate retinal vascular parameters by optical coherence tomography angiography (OCT-A) in iron deficiency anemia (IDA). Methods Thirty-two patients with IDA (study group) and 30 healthy children (control group) were enrolled in the study. All subjects underwent a complete ocular examination. OCT-A scans were performed in a 6???6 mm area centered on the macula. Foveal avascular zone (FAZ), non-flow area (NFA), FAZ perimeter (PERIM), acircularity index (AI) of FAZ, and foveal density (FD) were measured in the superficial capillary plexus (SCP) and deep capillary plexus (DCP). SCP and DCP were also scanned centered on the optic disk. Hemoglobin ...

(1) Aim: Contrasting results have been published on the effect of dark chocolate on visual function. The aim of this study was to evaluate retinal and choriocapillaris perfusion, using optical coherence tomography angiography (OCT-A), and visual function in healthy subjects following dark chocolate ingestion. (2) Methods: This prospective randomized study was carried out on 18 healthy young subjects at the St. Andrea Hospital, Sapienza, University of Rome. Visual acuity assessment and a complete ophthalmologic examination were carried out at baseline. In session one, each subject was randomized to eat either a 100 g dark chocolate bar or a 100 g ...

Purpose To determine the intensity of corneal pigmented arc in orthokeratology (ortho-k)-treated children and its correlation with wide epithelial thickness map (ETM) obtained through anterior segment optical coherent tomography (AS-OCT). Methods This retrospective case series reviews medical records of children who received ortho-k treatment for myopia control. Intensity of ortho-k-associated pigmented arc after wearing ortho-k lens more than 12 months and its correlation with each sector/zone of wide ETM obtained by AS-OCT was explored. Pigmented arcs were further divided into apparent and unapparent groups, and the clinical differences between groups were determined. Results This study included 57 eyes ...

Purpose Optical coherence tomography angiography (OCTA) was performed on patients with juvenile-onset type 1 diabetes (T1DM) but with no diabetic retinopathy to measure the foveal avascular zone (FAZ) area. Study Design Retrospective single-facility study Methods Twenty-nine patients (58 eyes) with juvenile-onset T1DM were studied. Images (3 mm x 3 mm cube centered on the fovea) were acquired using an OCTA device. Age at examination was 16.1 ? 8.7 years; onset age was 6.4 ? 3.5 years; duration of diabetes was 9.7 ? 8.3 years. Twenty-four age-matched healthy individuals were studied as controls. Results FAZ area was significantly ...

Laser ablation can be an effective modality for treatment, but it is complicated to apply continuous-wave (CW) light sources for laser ablation because of the unpredictable photothermal damage. In this study, an integrated theranostic system combining a low-cost CW laser diode with optical coherence tomography (OCT)/angiography (OCTA) was utilized for the in vivo ablation of tumor tissues. To examine the effect of laser exposure on tissue scattering characteristics, the OCT backscattering intensities of non-ablated and ablated tissues were analyzed, and the effect on the skin microvasculature produced by laser ablation was quantitatively evaluated. Moreover, the integrated system and the ...

Background To evaluate the effect of orthokeratology on precision of measurements in children using a new swept-source optical coherence tomography (SS-OCT) optical biometer (OA-2000), and agreement between its measurements and those provided by the commonly used IOLMaster based on partial coherence interferometry (PCI). Methods This study recruited fifty-one eyes of 51 normal children (8-16?years). An operator took measurements with the two biometers. Then, a second operator took measurements with the SS-OCT biometer. After orthokeratology was performed for one month, the same operators repeated the same procedures. Axial length (AL), mean keratometry (Km) at 2.5 mm and 3 ...

Purpose : To evaluate the relationship between visual acuity, visual field and spectral domain optical coherence tomography (OCT) parameters, including retinal nerve fiber layer (RNFL), ganglion cell-internal plexiform layer (GC-IPL) thicknesses, and optic nerve head parameters in patients with severe glaucoma. Material and Methods : Patients with the diagnosis of severe glaucoma were recruited from the data gathered at our glaucoma department. A detailed ophthalmic examination was performed using the Standard Automated Perimetry (the 30-2 SITA standard program was used for VF testing). Cirrus EDI-OCT was used for peripapillary RNFL and GC-IPL thickness measurements. Optic nerve head parameters, including mean cup-to-disc ...

Recent developments and commercial availability of low-noise and bright infrared (IR) supercontinuum sources initiated intensive applied research in the last few years. Covering a significant part of near- and mid-infrared spectral ranges, supercontinuum radiation opened up unique possibilities and alternatives for the well-established imaging technique of optical coherence tomography (OCT). In this contribution, we demonstrate the development, performance, and maturity of a cost-efficient dual-band Fourier-domain IR OCT system (2 ?m and 4 ?m central wavelengths). The proposed OCT setup is elegantly employing a single supercontinuum source and a pyroelectric linear array. We discuss adapted application-oriented approaches to signal acquisition and ...

Line-field confocal optical coherence tomography (LC-OCT) is an imaging technique in which A-scans are acquired in parallel through line illumination with a broadband laser and line detection with a line-scan camera. B-scan imaging at high spatial resolution is achieved by dynamic focusing in a Linnik interferometer. This paper presents an LC-OCT device based on a custom-designed Mirau interferometer that offers similar spatial resolution and detection sensitivity. The device has the advantage of being more compact and lighter. In vivo imaging of human skin with a resolution of 1.3 ?m ? 1.1 ?m (lateral ? axial) is demonstrated over a field ...

Purpose To describe the nystagmus characteristics of subjects with molecularly confirmed CNGB3 -associated achromatopsia and report the spectral domain optical coherence tomography (SD-OCT) findings in these individuals. Methods Adults and children with CNGB3 -achromatopsia underwent visual acuity testing, ocular motility assessments, video nystagmography, and SD-OCT imaging. Qualitative assessment of foveal structure was performed by grading SD-OCT images into one of five categories. Results A total of 18 subjects (11 adults) were included. The majority demonstrated a phoria, with manifest strabismus present in only 3 subjects. The predominant nystagmus waveform within the cohort was pure pendular. Nine individuals demonstrated a mixture ...

Purpose To estimate the central 10-degree visual field of glaucoma patients using en-face images obtained by optical coherence tomography (OCT), and to examine its usefulness. Patients and methods Thirty-eight eyes of 38 patients with primary open angle glaucoma were examined. En-face images were obtained by swept-source OCT (SS-OCT). Nerve fiber bundles (NFBs) on en-face images at points corresponding to Humphrey Field Analyzer (HFA) 10-2 locations were identified with retinal ganglion cell displacement. Estimated visual fields were created based on the presence/absence of NFBs and compared to actual HFA10-2 data. ? coefficients were calculated between probability plots of visual fields ...

The Skin Pathology assessment with Optical Technologies (SPOT) study aims to assess the feasibility of recently developed light-based skin imaging tools such as Optical Coherence Tomography (OCT) for the study of eczema (dermatitis [AD]). Tools such as OCT have enabled us to see beneath the skin surface, allowing us to see changes in our skin which are hidden and impossible to assess by eye, simply by shining harmless light into the skin. The investigators want to understand what these changes represent in the broader context of eczema. To do this, the investigators would like to recruit 60 volunteers who have ...

Retinopathy refers to any damage in the retina that causes visual impairments or even blindness. Identification of retinal lesions plays a vital role in accurately grading retinopathy and for its effective treatment. Optical coherence tomography (OCT) imaging is the most popular non-invasive technique used for the retinal examination due to its ability to screen abnormalities in early stages. Many researchers have presented studies on OCT based retinal image analysis over the past. However, to our best knowledge, there is no framework yet available which can extract retinal lesions from multi-vendor OCT scans and utilize them for the intuitive grading of ...

Biological functions rely on microvasculature to deliver oxygen and nutrients and carry away metabolic waste. Measuring microvascular oxygen saturation (sO2), the fraction of oxygensaturated hemoglobin relative to total hemoglobin (unsaturated + saturated) in the blood, can assess tissue oxygenation and provide insights into tissue metabolism, inflammation, and oxygen-related pathologies. Several major diseases, such as cancer, diabetes mellitus, cardiovascular diseases, hypertension, chronic kidney disease, and neurodegenerative diseases, are related to local microvascular sO2. Therefore, it is of crucial importance to demonstrate an accurate and reliable method to measure microvascular sO2 for early diagnosis, monitoring disease progression, and evaluating treatments of oxygen metabolism ...

While optical coherence tomography (OCT) provides a resolution down to 1 micrometer it has difficulties to visualize cellular structures due to a lack of scattering contrast. By evaluating signal fluctuations, a significant contrast enhancement was demonstrated using time-domain full-field OCT (FF-OCT), which makes cellular and subcellular structures visible. The putative cause of the dynamic OCT signal is ATP-dependent motion of cellular structures in a sub-micrometer range, which provides histology-like contrast. Here we demonstrate dynamic contrast with a scanning frequency-domain OCT (FD-OCT). Given the inherent sectional imaging geometry, scanning FD-OCT provides depth-resolved images across tissue layers, a perspective known from histopathology ...

Spatially resolved data for biofilm structure can often not be assessed easily in bioelectrochemical setups due to the orientation and placement of anode and cathode. However, understanding the interplay of biofilm (structure) development and electrochemical parameters is crucial for optimizing bioelectrochemical biofilm systems. For example, to produce value added products. This study thus, presents a versatile flow cell setup allowing for control of hydrodynamic, substrate (liquid and gaseous), and nutritional conditions as well as physical parameters. Here, a versatile lab-scale flow cell system equipped with a cathode and an anode is presented to monitor the growth of Kyrpidia spormannii biofilm ...

Background: Much remains unknown about the influence of severity of prematurity and presence of retinopathy of prematurity (ROP) on the development of the fovea after preterm birth during the perinatal period from postmenstrual age (PMA) 30 to 44 weeks. Aims: Measures of foveal morphology, individual retinal layers and foveal oedema (CME), with and without ROP using HH-OCT, adjusting for gestational age (GA) and birthweight (BW). Methods: Prospective mixed cross-sectional and longitudinal study of infants (23 to 36 weeks GA). Foveal width, area, depth, central foveal thickness (CFT), individual retinal layers and CME severity were analysed. Infants with ROP were included ...

Purpose: To propose a simple non-invasive method for screening patients at risk for angle closure using anterior segment OCT. Methods: Scans of nasal and temporal iridocorneal angles in glaucoma suspect patients were performed using OCT. Upon identifying Schwalbe's line, the integrated caliper tool was used to draw a line to the nearest point of the iris to produce a measure 'S-I'. Gonioscopy was performed and angles graded according to Shaffer's classification to assess the correlation between both methods. Results: Thirty-four images were available for analysis. Spearman correlation coefficients between S-I anf gonioscopy grades were 0.81 for nasal ...

Endoscopic optical coherence tomography (OCT) has many promising applications in the fields of medical research and clinical diagnosis. In this letter, we present a side-viewing endoscopic OCT probe based on a gradient index (GRIN) lens with an air gap. By adjusting the length of the air gap the optical performance of the probe can be flexibly tuned. The quantitative relationships between the optical performance parameters of the probe and its structural parameters are theoretically analyzed by using the ABCD beam transfer matrix theory. The developed probe has a maximum diameter of 1.4 mm and a rigid length of 11 ...

This open access book provides a comprehensive overview of the application of the newest laser and microscope/ophthalmoscope technology in the field of high resolution imaging in microscopy and ophthalmology. Starting by describing High-Resolution 3D Light Microscopy with STED and RESOLFT , the book goes on to cover retinal and anterior segment imaging and image-guided treatment and also discusses the development of adaptive optics in vision science and

Purpose To determine the comparability of choroidal thickness (ChT) measurements using swept source (SS) and spectral domain (SD) optical coherence tomography (OCT) devices in patients with pachychoroid diseases. Methods Patients with pachychoroid diseases were recruited. OCT scans were performed sequentially with a Cirrus HD OCT 5000 and Plex Elite 9000. Images were analyzed by two independent observers. Each image was independently measured twice by each observer to determine the intraobserver repeatability. Results A total of 55 eyes were included. The average ChT of the subfoveal area using SS-OCT and SD-OCT was 430.5 ? 68.1 and 428.5 ? 57.9 ...

Microfabricated neuroprosthetic devices have made possible important observations on neuron activity; however, long-term high-fidelity recording performance of these devices has yet to be realized. Tissue-device interactions appear to be a primary source of lost recording performance. The current state of the art for visualizing the tissue response surrounding brain implants in animals is Immunohistochemistry + Confocal Microscopy, which is mainly performed after sacrificing the animal. Monitoring the tissue response as it develops could reveal important features of the response which may inform improvements in electrode design. Optical Coherence Tomography (OCT), an imaging technique commonly used in ophthalmology, has already been adapted ...

Optical coherence tomography angiography (OCTA) is a promising imaging modality for microvasculature studies. Meanwhile, deep learning has achieved rapid development in image-to-image translation tasks. Some studies have proposed applying deep learning models to OCTA reconstruction and have obtained preliminary results. However, current studies are mostly limited to a few specific deep neural networks. In this paper, we conducted a comparative study to investigate OCTA reconstruction using deep learning models. Four representative network architectures including single-path models, U-shaped models, generative adversarial network (GAN)-based models and multi-path models were investigated on a dataset of OCTA images acquired from rat brains. Three ...

Purpose The aim of this study was to evaluate the foveal avascular zone (FAZ) in patients with diabetic macular edema (DME) by documenting the morphological and quantitative changes by optical coherence tomography angiography (OCTA). Patients and methods The study included 47 eyes of 47 participants. They were allocated into two groups: 27 eyes of 27 patients having DME and 20 eyes of 20 age-matched healthy controls. All study participants were imaged using OCTA machine to assess the FAZ area and to compare the changes between patients and controls. Results The FAZ area was significantly enlarged in patients with DME than ...

Objective To describe the prevalence of vitreomacular interface (VMI) features classified using spectral-domain optical coherence tomography (SD-OCT) and their associated risk factors in the Northern Ireland Cohort for the Longitudinal Study of Ageing (NICOLA Study). Design Cross-sectional population-based study Participants Non-institutionalised Northern Irish adults aged ?40 years. Methods Using geographic stratification, a representative sample of people in Northern Ireland was invited to participate in the NICOLA Study. SD-OCT images of participants were graded for vitreomacular traction (VMT), macular hole (MH) and epiretinal membrane (ERM) according to the International Vitreomacular Traction Study (IVTS) Group. A subsample was graded in more detail ...

Background/aims Quantitative analysis of optical coherence tomography angiography (OCT-A) images requires a reproducible approach that accounts for sectoral loss. The objective of this study was to determine whether an index that accounts for both global (perfusion density, PD) and asymmetric loss of perfusion, rather than PD alone, more reliably measures loss of perfusion in patients with glaucoma. Methods We analysed macular OCT-A scans of 95 glaucoma patients and 59 control subjects. Two-dimensional projection images corresponding to the superficial vascular plexus were exported and analyses performed to calculate global PD and image asymmetry. An unsigned perfusion asymmetry index (PAI) that ...

A 52-year-old female was referred to our catheterization lab due to chest pain and stress-induced myocardial inferior ischemia. Coronary angiography revealed an abnormal segment of the right coronary artery (RCA); its lumen was divided into thin channels with a twisting course reassembling into a single normal lumen in the distal segment of the RCA with TIMI 3 blood flow (Figure 1A; Video 1 ). Optical coherence tomography (OCT) was performed to confirm the presence of a woven coronary artery anomaly (WCAA) (Figure 1B). The similarity of the angiogram to the braided hair gives the name to this entity. WCAA was first ...

Background: To evaluate the potential of vessel density alterations for predicting postoperative visual field (VF) improvement in chiasmal compression using optical coherence tomography angiography (OCT-A). Methods: The study investigated 57 eyes of 57 patients diagnosed with pituitary tumors and 42 eyes of 42 age and refractive error matched controls. All eyes with chiasmal compression for which preoperative optical coherence tomography (OCT) and OCT-A, and pre- and postoperative VF data were available. Preoperative vessel densities of superficial retinal capillary plexus (SRCP), deep retinal capillary plexus (DRCP), and radial peripapillary capillary (RPC) segment were utilized by OCT-A. Results: Preoperative peripapillary retinal nerve ...

Optical coherence tomography (OCT) is an optical high-resolution imaging technique for ophthalmic diagnosis. In this paper, we take advantages of multi-scale input, multi-scale side output and dual attention mechanism and present an enhanced nested U-Net architecture (MDAN-UNet), a new powerful fully convolutional network for automatic end-to-end segmentation of OCT images. We have evaluated two versions of MDAN-UNet (MDAN-UNet-16 and MDAN-UNet-32) on two publicly available benchmark datasets which are the Duke Diabetic Macular Edema (DME) dataset and the RETOUCH dataset, in comparison with other state-of-the-art segmentation methods. Our experiment demonstrates that MDAN-UNet-32 achieved the best performance, followed by MDAN-UNet-16 with smaller ...

When Ian Sigal was a PhD student researching glaucoma-a group of disorders marked by damage to the optic nerve-he and his advisor homed in on those dying nerve fibers for their studies. But soon, they realized they couldn't understand what was going on there without also checking in on the optic nerve's nearby neighbors. So they widened their scope a tad. "Then we found, of course, that no, that's not enough," Sigal says. You have to look around that area, then you have to look around that. So they kept expanding their scope. In time ...

To review visual outcomes in untreated premacular membrane (PMM) with macular pucker (MP) and evaluate novel predictors of progression. Methods: In this retrospective observation study, we included 342 eyes with untreated PMM with MP between 2012 and 2015. PMMs were characterized by spectral-domain optical coherence tomography (SD-OCT) imaging based on foveal morphologies, number of retinal contraction centers, central subfield thickness (CST), inner segment ellipsoid band integrity, and photoreceptor deformation index. Additionally, the thickened retina portion was identified by en face OCT and processed digitally to calculate its area. Parameters were retrospectively analyzed using multiple regression analyses to identify associations with ...

A direct scattering optical coherence tomography forward model was developed to simulate A-scans for both idealized and real light sources on an arbitrary given sample structure. Previous models neglected absorption, scattering, and multiple reflections at interfacial layers, and so two extended models were developed to investigate the impact of these processes. The first model uses the Beer-Lambert law to incorporate both absorption and scattering optical processes, and the second model uses a recursive form to model multiple reflections. These models were tested on a structure representative of a multilayered skin sample. The results show that the absorption and scattering ...

One or more devices, systems, methods and storage mediums for performing continuously, full range optical coherence tomography (OCT) without losing A-lines are provided. Examples of such applications include imaging, evaluating and diagnosing biological objects, such as, but not limited to, for cardio and/or ophthalmic applications, and being obtained via one or more optical instruments, such as, but not limited to, optical probes (e.g., common path probes), catheters, endoscopes, phase shift units (e.g., galvanometer scanner) and bench top systems. Preferably, the OCT devices, systems methods and storage mediums include or involve a phase shift device including at least ...

Methods and apparatus are presented for obtaining high-resolution 3-D images of a sample over a range of wavelengths, optionally with polarisation-sensitive detection. In preferred embodiments a spectral domain OCT apparatus is used to sample the complex field of light reflected or scattered from a sample, providing full range imaging. In certain embodiments structured illumination is utilised to provide enhanced lateral resolution. In certain embodiments the resolution or depth of field of images is enhanced by digital refocusing or digital correction of aberrations in the sample. Individual sample volumes are imaged using single shot techniques, and larger volumes can be imaged ...

Purpose: To measure marginal reflex distance-1 (MRD-1) values in normal subjects and patients with blepharoptosis using second-generation swept-source anterior segment optical coherence tomography (AS-OCT) and to evaluate the usefulness of this measurement method. Materials and Methods: MRD-1 values were measured using AS-OCT in 80 eyes of 40 normal subjects (16 men and 24 women) aged 20- 59 years with no neurological or endocrinological disorders, and the measured values were compared between four age groups comprising 20 eyes of 10 subjects each in their 20s, 30s, 40s, and 50s. The Volk Eye Check system was simultaneously used to measure MRD-1 in ...

Purpose: To assess the utility of microscope-integrated intraoperative optical coherence tomography (Mi-OCT) for performing Descemet membrane endothelial keratoplasty (DMEK) in corneas with poor visualization. Methods: It is a prospective interventional case series that included 25 consecutive cases of corneal decompensation with poor visualization that underwent Mi-OCT-guided DMEK at a tertiary eye care centre. The main outcome measures were graft attachment on day 3 and requirement for re-bubbling. Results: The etiology for corneal decompensation was pseudophakic bullous keratopathy (n=17), Fuchs endothelial corneal dystrophy (n=4), failed graft (n=2), iridocorneal endothelial syndrome (n=1) and failed Descemet stripping automated endothelial ...

Optical coherence tomography angiography (OCTA) is a revolutionary method in the visualization of the vascular system in different retinal and choroidal layers. During the last 4 years since the commercial availability of different OCTA devices, attempts have been made to utilize this technology in various aspects of ocular oncology from the differentiation of benign and malignant lesions to assisting in evaluation of post-treatment complications, such as radiation retinopathy. However, current OCTA technology is restricted by various artefacts and inherent limitations, some of which are more pronounced in the presence of elevated tumoural lesions. Imminent advancements in OCTA systems and image ...

An OCI medical device includes a coherent light source, a light sensor, a first processing unit adapted to calculate OCI Data from the light sensor, a control unit which allows taking or loading of at least one Reference OCI Value, a second processing unit adapted to calculate the Intra-Individual Relative Assessment of the OCI Data of an Imaging Zone and the at least one OCI Reference Value, and display means adapted to show at least one Relative OCI Value. Uses and a method for assessing the blood flow of a body region use OCI imaging and include an Intra-Individual Relative ...

The present disclosure describes systems and method for generating surgical maps that provide a surgeon with information regarding the placement of features of interest. More particularly, the system is configured to display optical coherence tomography (OCT) images to a medical professional. The medical professional can select anatomical features, biomarkers, and other features of interest within each of the OCT images. The system can then translate the location of the features of interest within the OCT images to an en face image to generate a map of the features that the medical professional can use for surgical guidance.

Complex interactions between roots and soil provide the nutrients and physical support required for robust plant growth. Yet, visualizing the root-soil interface is challenged by soil's opaque scattering characteristics. Herein, we describe methods for using optical coherence tomography (OCT) to provide non-destructive 3D and cross-sectional root imaging not available with traditional bright-field microscopy. OCT is regularly used for bioimaging, especially in ophthalmology, where it can detect retinal abnormalities. Prior use of OCT in plant biology has focused on surface defects of above-ground tissues, predominantly in food crops. Our results show OCT is also viable for detailed, in situ ...

Retinopathy refers to any damage in the retina that causes visual impairments or even blindness. Identification of retinal lesions plays a vital role in accurately grading retinopathy and for its effective treatment. Optical coherence tomography (OCT) imaging is the most popular non-invasive technique used for the retinal examination due to its ability to screen abnormalities in early stages. Many researchers have presented studies on OCT based retinal image analysis over the past. However, to our best knowledge, there is no framework yet available which can extract retinal lesions from multi-vendor OCT scans and utilize them for the intuitive grading of ...

Biological functions rely on microvasculature to deliver oxygen and nutrients and carry away metabolic waste. Measuring microvascular oxygen saturation (sO2), the fraction of oxygensaturated hemoglobin relative to total hemoglobin (unsaturated + saturated) in the blood, can assess tissue oxygenation and provide insights into tissue metabolism, inflammation, and oxygen-related pathologies. Several major diseases, such as cancer, diabetes mellitus, cardiovascular diseases, hypertension, chronic kidney disease, and neurodegenerative diseases, are related to local microvascular sO2. Therefore, it is of crucial importance to demonstrate an accurate and reliable method to measure microvascular sO2 for early diagnosis, monitoring disease progression, and evaluating treatments of oxygen metabolism ...