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We demonstrate the feasibility of swept-source visible-light optical coherence tomography (SS-vis-OCT). We used a fanout periodically poled lithium niobate (PPLN) crystal for second-harmonic generation (SHG) to convert a commercial near-infrared swept-source (NIR-SS) laser into a visible-light SS laser. To enhance SHG efficiency, we amplified the NIR-SS output with booster optical amplifiers (BOAs) and generated up to 580 µW of power. The SS-vis-OCT achieved a maximum axial resolution of 7.3 µm and an imaging depth of 5 mm in air, corresponding to 5.4 µm and 3.7 mm in tissue (n = 1.35). Compared with spectral-domain vis-OCT, SS-vis-OCT provides a 2.2-fold increased imaging depth and a 2.8-fold improved roll-off. Additionally, we validated SS-vis-OCT performance using a 3D-printed pyramid phantom, with its feature measurements cross-validated by scanning electron microscopy (SEM).
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http://dx.doi.org/10.1364/OL.544499 | DOI Listing |
Invest Ophthalmol Vis Sci
August 2025
Department of Ophthalmology, University of California San Francisco, San Francisco, California, United States.
Purpose: To investigate longitudinal changes in cone structure, choriocapillaris, and retinal sensitivity in choroideremia.
Methods: We assessed cone spacing z scores using adaptive optics scanning light ophthalmoscopy, analyzed choriocapillaris flow deficits (CCFDs) on swept-source optical coherence tomography angiography, and measured retinal sensitivity via microperimetry. Linear mixed-effects models estimated annual change rates in these parameters.
Biomed Opt Express
August 2025
Eye Hospital and School of Ophthalmology and Optometry, Wenzhou Medical University, Wenzhou, Zhejiang, China.
The drawbacks of repeated excitations and long imaging time in wave-based optical coherence elastography limited its application in ophthalmology. In this study, we put forward a swept source scanning optical coherence elastography (SSS-OCE) system based on the wavelength-dependence scanning technique. A dispersive element was employed to achieve ultra-fast line scanning from swept light source.
View Article and Find Full Text PDFToday, molecular analysis at multiple locations requires either transporting samples to a central laboratory via transportation or conveyor networks or deploying independent analyzers at each sampling point. Neither of these approaches offers the accessibility and scalability we have come to expect from modern utility infrastructure that provides access to water, electricity, information (internet), and computation resources. Here, we demonstrate a novel parallel, distributed, optical fiber swept-source Raman spectroscopy approach that replaces spectrometers with compact semiconductor tunable lasers along with high-collection power fiber-optic probes and sensitive single photon avalanche detectors (SPAD) photodetectors.
View Article and Find Full Text PDFBMC Ophthalmol
July 2025
Department of Ophthalmology, Samsung Medical Center, Sungkyunkwan University School of Medicine, 81 Irwon-ro, Gangnam-gu, Seoul, 06351, Korea.
Background: This study aims to develop a deep learning-based algorithm dedicated to the automated classification of choroidal layers in en face swept-source optical coherence tomography (SS-OCT) images of the eye.
Methods: A cohort of 117 healthy subjects (117 eyes), underwent SS-OCT volume scans covering a 12 × 9 mm range. En face SS-OCT images of the choroid were acquired at 2.
Ophthalmol Ther
August 2025
AIBILI - Association for Innovation and Biomedical Research on Light and Image, Coimbra, Portugal.
Introduction: This study aimed to investigate the utility of microaneurysm (MA) counting as a tool for characterizing the hyperperfusion stage of nonproliferative diabetic retinopathy (NPDR) and to examine the hypothesis that MAs can serve as a surrogate biomarker for the presence of intraretinal microvascular abnormalities (IRMAs).
Methods: Forty-nine (n = 49) eyes with type 2 diabetes mellitus with NPDR were included in this analysis: 12 with Early Treatment Diabetic Retinopathy Study (ETDRS) levels 43 and 37 with levels 47-53. Automated MA detection was performed using the RetmarkerDR software (Retmarker SA, Meteda Group, Italy), alongside manual detection, both done in the central retina (field 2).