Significance: Imaging deep structures with optical coherence tomography (OCT) is difficult in highly scattering biological tissue, such as the sclera. There is a need to visualize the suprachoroidal space and choroid through the sclera to study suprachoroidal drug delivery.
Aim: We aim to develop optical methods to image through the highly scattering sclera with a custom-built OCT system to visualize the suprachoroidal space and drug delivery within.
Significance: Imaging deep structures with optical coherence tomography (OCT) is difficult in highly scattering biological tissue, such as the sclera. There is a need to visualize the suprachoroidal space and choroid through the sclera to study suprachoroidal drug delivery.
Aim: We aim to develop optical methods to image through the highly scattering sclera with a custom-built OCT system to visualize the suprachoroidal space and drug delivery within.
Suprachoroidal injections are a relatively new method of drug delivery to treat retinal disease. At present, it is difficult to visualize the distribution of injection-delivered product beneath the sclera into the suprachoroidal space. Imaging the suprachoroidal space with OCT is hindered by scattering of light from densely packed collagen fibers of the sclera, limiting depth penetration of the OCT light.
View Article and Find Full Text PDFPurpose: To develop a quantitative tool for assessing the posterior ocular shape using widefield, volumetric optical coherence tomography (OCT) in eyes with myopia.
Methods: This observational, cross-sectional study included 178 eyes from 113 participants. Participants underwent a standardized eye examination, including ocular biometry and a custom ultrawide OCT.
Objective: To evaluate the published literature on the efficacy of amniotic membrane grafting (AMG) in the management of acute chemical and thermal ocular surface burns with respect to the rate of corneal re-epithelialization and improvement of visual acuity or corneal clarity.
Methods: Literature searches were conducted in the PubMed database in May 2023 and updated in January 2024 and were limited to the English language without date restrictions. The searches yielded 474 citations; 58 were reviewed in full text, and 9 met the inclusion criteria.
Point scanning retinal imaging modalities, including confocal scanning light ophthalmoscopy (cSLO) and optical coherence tomography, suffer from fixational motion artifacts. Fixation targets, though effective at reducing eye motion, are infeasible in some applications (e.g.
View Article and Find Full Text PDFPurpose: To review the published literature on the safety and outcomes of keratolimbal allograft (KLAL) transplantation and living-related conjunctival limbal allograft (lr-CLAL) transplantation for bilateral severe/total limbal stem cell deficiency (LSCD).
Methods: Literature searches were last conducted in the PubMed database in February 2023 and were limited to the English language. They yielded 523 citations; 76 were reviewed in full text, and 21 met the inclusion criteria.
Purpose: To evaluate the diagnostic performance of a robotically aligned optical coherence tomography (RAOCT) system coupled with a deep learning model in detecting referable posterior segment pathology in OCT images of emergency department patients.
Methods: A deep learning model, RobOCTNet, was trained and internally tested to classify OCT images as referable versus non-referable for ophthalmology consultation. For external testing, emergency department patients with signs or symptoms warranting evaluation of the posterior segment were imaged with RAOCT.
Purpose: To review the published literature on the diagnostic capabilities of the newest generation of corneal imaging devices for the identification of keratoconus.
Methods: Corneal imaging devices studied included tomographic platforms (Scheimpflug photography, OCT) and functional biomechanical devices (imaging an air impulse on the cornea). A literature search in the PubMed database for English language studies was last conducted in February 2023.
[This corrects the article on p. 3308 in vol. 14, PMID: 37497493.
View Article and Find Full Text PDFHigh-speed, accessible, and robust imaging of the human retina is critical for screening of retinal pathologies, such as diabetic retinopathy, age-related macular degeneration, and others. Scanning light ophthalmoscopy (SLO) is a retinal imaging modality that produces digital, images of the human retina with superior image gradability rates when compared to the current standard of care in screening for these diseases, namely the flood-illumination handheld fundus camera (HFC). However, current-generation commercial SLO systems are mostly tabletop devices, limiting their accessibility and utility in screening applications.
View Article and Find Full Text PDFOphthalmic microsurgery is traditionally performed using stereomicroscopes and requires visualization and manipulation of sub-millimeter tissue structures with limited contrast. Optical coherence tomography (OCT) is a non-invasive imaging modality that can provide high-resolution, depth-resolved cross sections, and has become a valuable tool in clinical practice in ophthalmology. While there has been substantial progress in both research and commercialization efforts to bring OCT imaging into live surgery, its use is still somewhat limited due to factors such as low imaging speed, limited scan configurations, and suboptimal data visualization.
View Article and Find Full Text PDF4D-microscope-integrated optical coherence tomography (4D-MIOCT) is an emergent multimodal imaging technology in which live volumetric OCT (4D-OCT) is implemented in tandem with standard stereo color microscopy. 4D-OCT provides ophthalmic surgeons with many useful visual cues not available in standard microscopy; however it is challenging for the surgeon to effectively integrate cues from simultaneous-but-separate imaging in real-time. In this work, we demonstrate progress towards solving this challenge via the fusion of data from each modality guided by segmented 3D features.
View Article and Find Full Text PDFBackground: Despite the increased emphasis on evidence-based medicine, the current state of evidence behind ophthalmology clinical practice guidelines is unknown. The purpose of this systematic analysis was to understand the levels of evidence (LOE) supporting American Academy of Ophthalmology (AAO) Preferred Practice Pattern (PPP) guidelines, assess changes over time, and compare LOE across ophthalmology subspecialties.
Methods: All current PPP guidelines and their immediate predecessors were comprehensively reviewed to identify all recommendations with LOE provided (I [randomized controlled trials], II [case-control or cohort studies], and III [nonanalytic studies]).
Ophthalmic optical coherence tomography (OCT) has achieved remarkable clinical success but remains sequestered in ophthalmology specialty offices. Recently introduced robotic OCT systems seek to expand patient access but fall short of their full potential due to significant imaging workspace and motion planning restrictions. Here, we present a next-generation robotic OCT system capable of imaging in any head orientation or posture that is mechanically reachable.
View Article and Find Full Text PDFStudy Objective: To evaluate the diagnostic performance of emergency physicians' interpretation of robotically acquired retinal optical coherence tomography images for detecting posterior eye abnormalities in patients seen in the emergency department (ED).
Methods: Adult patients presenting to Duke University Hospital emergency department from November 2020 through October 2021 with acute visual changes, headache, or focal neurologic deficit(s) who received an ophthalmology consultation were enrolled in this pilot study. Emergency physicians provided standard clinical care, including direct ophthalmoscopy, at their discretion.
Optical coherence tomography (OCT) may be useful for guidance of ocular microsurgeries such as deep anterior lamellar keratoplasty (DALK), a form of corneal transplantation that requires delicate insertion of a needle into the stroma to approximately 90% of the corneal thickness. However, visualization of the true shape of the cornea and the surgical tool during surgery is impaired in raw OCT volumes due to both light refraction at the corneal boundaries, as well as geometrical optical path length distortion due to the group velocity of broadband OCT light in tissue. Therefore, uncorrected B-scans or volumes may not provide an accurate visualization suitable for reliable surgical guidance.
View Article and Find Full Text PDFImportance: Primary care professionals (PCPs) have a central role in screening for diabetic retinopathy (DR), especially in settings where access to specialty eye care is limited. Data on current DR screening practice patterns in primary care are needed to inform screening strategies.
Objectives: To assess the practice patterns of fundoscopic examination for DR screening in a large primary care network and to evaluate the sensitivity and accuracy of PCP fundoscopy for detecting DR.
We propose an empirical distortion correction approach for optical coherence tomography (OCT) devices that use a fan-scanning pattern to image the posterior eye segment. Two types of reference markers were used to empirically estimate the distortion correction approach in tree shrew eyes: retinal curvature from MRI images and implanted glass beads of known diameter. Performance was tested by correcting distorted images of the optic nerve head.
View Article and Find Full Text PDFOptical coherence tomography (OCT) has revolutionized diagnostics in ophthalmology. However, OCT requires a trained operator and patient cooperation to carefully align a scanner with the subject's eye and orient it in such a way that it images a desired region of interest at the retina. With the goal of automating this process of orienting and aligning the scanner, we developed a robot-mounted OCT scanner that automatically aligned with the pupil while matching its optical axis with the target region of interest at the retina.
View Article and Find Full Text PDFOcular deformation may be associated with biomechanical alterations in the structures of the eye, especially the cornea and sclera in conditions such as keratoconus, congenital glaucoma, and pathological myopia. Here, we propose a method to estimate ocular shape using an ultra-wide field MHz swept-source optical coherence tomography (SS-OCT) with a Fourier Domain Mode-Locked (FDML) laser and distortion correction of the images. The ocular biometrics for distortion correction was collected by an IOLMaster 700, and localized Gaussian curvature was proposed to quantify the ocular curvature covering a field-of-view up to 65°×62°.
View Article and Find Full Text PDFClinical systems for optical coherence tomography (OCT) are used routinely to diagnose and monitor patients with a range of ocular diseases. They are large tabletop instruments operated by trained staff, and require mechanical stabilization of the head of the patient for positioning and motion reduction. Here we report the development and performance of a robot-mounted OCT scanner for the autonomous contactless imaging, at safe distances, of the eyes of freestanding individuals without the need for operator intervention or head stabilization.
View Article and Find Full Text PDFAnterior uveitis is the most common form of intraocular inflammation, and one of its main signs is the presence of white blood cells (WBCs) in the anterior chamber (AC). Clinically, the true composition of cells can currently only be obtained using AC paracentesis, an invasive procedure to obtain AC fluid requiring needle insertion into the AC. We previously developed a spectroscopic optical coherence tomography (SOCT) analysis method to differentiate between populations of RBCs and subtypes of WBCs, including granulocytes, lymphocytes and monocytes, both and in ACs of excised porcine eyes.
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