Taeyoon Son

University of Illinois at Chicago | UIC · Department of Bioengineering

Blood flow changes are highly related to neural activities in the retina. It has been reported that neural activity increases when flickering light stimulation of the retina is used. It is known that blood flow changes with flickering light stimulation can be altered in patients with vascular disease and that measurement of flicker-induced vasodila...

Given the several difficulties associated with histology, including difficulty in continuous monitoring, this study aimed to investigate the feasibility of optical imaging modalities-cross-polarization color (CPC) imaging, erythema index (EI) imaging, and laser speckle contrast (LSC) imaging-for continuous evaluation and monitoring of arthritis in...

Various methods have been proposed for enhancing the contrast of laser speckle contrast image (LSCI) in subcutaneous blood flow measurements. However, the LSCI still suffers from low image contrast due to tissue turbidity. Herein, a physicochemical tissue optical clearing (PCTOC) method was employed to enhance the contrast of LSCI. Ex vivo and in v...

Light scattering in biological tissues can be reduced by using optical clearing agents. Various physical methods in conjunction with agents have been studied to enhance the optical clearing efficacy of skin for diagnostic and therapeutic applications. In this study, we propose a new physical method to enhance the optical clearing potential of topic...

The wall-to-lumen ratio (WLR) of retinal blood vessels promises a sensitive marker for the physiological assessment of eye conditions. However, in vivo measurement of vessel wall thickness and lumen diameter is still technically challenging, hindering the wide application of WLR in research and clinical settings. In this study, we demonstrate the f...

A custom-built optical coherence tomography (OCT) was used for time-lapse imaging of mouse retinas with flicker stimulation. Stimulus-evoked vessel lumen changes of individual arteries and veins were quantitatively evaluated. Comparative analysis revealed significantly larger (18.21%) lumen dilation in axial direction compared to lateral (10.77%) d...

A custom-built optical coherence tomography (OCT) was used for time-lapse imaging of mouse retinas with flicker stimulation. Stimulus-evoked vessel lumen changes of individual arteries and veins were quantitatively evaluated. Comparative analysis revealed significantly larger (18.21%) lumen dilation in axial direction compared to lateral (10.77%) d...

The purpose of this study is to demonstrate the feasibility of using polarization maintaining photons for enhanced contrast imaging of the retina. Orthogonal-polarization control has been frequently used in conventional fundus imaging systems to minimize reflection artifacts. However, the orthogonal-polarization configuration also rejects the direc...

Multi-spectral widefield fundus photography is valuable for the clinical diagnosis and management of ocular conditions that may impact both central and peripheral regions of the retina and choroid. Trans-palpebral illumination has been demonstrated as an alternative to transpupillary illumination for widefield fundus photography without requiring p...

Neuronal hyperexcitability promises an early biomarker of Alzheimer’s disease (AD). However, in vivo detection of neuronal hyperexcitability in the brain is technically challenging. The retina, one part of the central nervous system, presents a unique window for noninvasive monitoring of the brain function. This study aims to test the feasibility o...

The wall-to-lumen ratio (WLR) of retinal blood vessels promises a sensitive marker for physiological assessment of eye conditions. However, in vivo measurement of vessel wall thickness and lumen diameter is still technically challenging, hindering wide application of WLR in research and clinical settings. In this study, we demonstrate the feasibili...

The wall-to-lumen ratio (WLR) of retinal blood vessels promises a sensitive marker for physiological assessment of eye conditions. However, in vivo measurement of vessel wall thickness and lumen diameter is still technically challenging, hindering wide application of WLR in research and clinical settings. In this study, we demonstrate the feasibili...

Neuronal hyperexcitability promises an early biomarker of Alzheimer's disease (AD). However, in vivo detection of neuronal hyperexcitability in the brain is technically challenging. The retina, one part of the central nervous system, presents a unique window for noninvasive monitoring of brain function. This study aims to test the feasibility of us...

Neuronal hyperexcitability promises an early biomarker of Alzheimer's disease (AD). However, in vivo detection of neuronal hyperexcitability in the brain is technically challenging. The retina, one part of the central nervous system, presents a unique window for noninvasive monitoring of brain function. This study aims to test the feasibility of us...

The purpose of this study is to demonstrate the feasibility of using polarization maintaining photons for enhanced contrast imaging of the retina. Orthogonal-polarization control has been frequently used in conventional fundus imaging systems to minimize reflection artifacts. However, the orthogonal-polarization configuration also rejects the direc...

The purpose of this study is to demonstrate the feasibility of using polarization maintaining photons for enhanced contrast imaging of the retina. Orthogonal-polarization control has been frequently used in conventional fundus imaging systems to minimize reflection artifacts. However, the orthogonal-polarization configuration also rejects the direc...

Major retinopathies can differentially impact the arteries and veins. Traditional fundus photography provides limited resolution for visualizing retinal vascular details. Optical coherence tomography (OCT) can provide improved resolution for retinal imaging. However, it cannot discern capillary-level structures due to the limited image contrast. As...

Multi-spectral widefield fundus photography is valuable for the clinical diagnosis and ‎management of ocular conditions that may impact both central and peripheral regions of the ‎retina and choroid. Trans-palpebral illumination has been demonstrated as an alternative to ‎transpupillary illumination for widefield fundus photography without requirin...

Multi-spectral widefield fundus photography is valuable for the clinical diagnosis and ‎management of ocular conditions that may impact both central and peripheral regions of the ‎retina and choroid. Trans-palpebral illumination has been demonstrated as an alternative to ‎transpupillary illumination for widefield fundus photography without requirin...

Purpose: To evaluate the sensitivity of normalized blood flow index (NBFI) for detecting early diabetic retinopathy (DR). Methods: Optical coherence tomography angiography (OCTA) images of healthy controls, diabetic patients without DR (NoDR), and patients with mild nonproliferative DR (NPDR) were analyzed in this study. The OCTA images were cen...

Accurate image registration is essential for eye movement compensation in optical coherence tomography (OCT) and OCT angiography (OCTA). The spatial resolution of an OCT instrument is typically anisotropic, i.e., has different resolutions in the lateral and axial dimensions. When OCT images have anisotropic pixel resolution, residual distortion (RD...

Purpose: To assess quantitative characteristics of optical coherence tomography (OCT) and OCT angiography (OCTA) for objective detection of early diabetic retinopathy (DR). Methods: This was a retrospective and cross-sectional study which was carried out at a tertiary academic practice with a subspecialty. Twenty control participants, fifteen di...

Fundus photography is indispensable for the clinical detection and management of eye diseases. Low image contrast and small field of view (FOV) are common limitations of conventional fundus photography, making it difficult to detect subtle abnormalities at the early stages of eye diseases. Further improvements in image contrast and FOV coverage are...

We report here a portable widefield fundus camera with high dynamic range (HDR) imaging capability. The effectiveness of HDR imaging was validated with both normal healthy and pathologic eyes.

Purpose: To evaluate the sensitivity of normalized blood flow index (NBFI) for detecting early diabetic retinopathy (DR). Methods: Optical coherence tomography angiography (OCTA) images of 30 eyes from 20 healthy controls, 21 eyes of diabetic patients with no DR (NoDR) and 26 eyes from 22 patients with mild non-proliferative DR (NPDR) were analyzed...

Fundus photography is indispensable for clinical detection and management of eye diseases. Limited image contrast and field of view (FOV) are common limitations of conventional fundus cameras, making it difficult to detect subtle abnormalities at the early stages of eye diseases. Further improvements of image contrast and FOV coverage are important...

Accurate image registration is essential for eye movement compensation in optical coherence tomography (OCT) and OCT angiography (OCTA). The spatial resolution of an OCT instrument is typically anisotropic, i.e., different resolutions in the lateral and axial dimensions. When OCT images have anisotropic pixel resolution, residual distortion (RD) an...

As one modality extension of optical coherence tomography (OCT), OCT angiography (OCTA) provides unparalleled capability for depth-resolved visualization of retinal vasculature at the microcapillary level resolution. For OCTA image construction, repeated OCT scans from one location are required for temporally vascular connectivity (TVC), i.e., OCT...

A wide-field fundus camera, which can selectively evaluate the retina and choroid, is desirable for better detection and treatment evaluation of eye diseases. Trans-palpebral illumination has been demonstrated for wide-field fundus photography, but its application for true-color retinal imaging is challenging due to the light efficiency delivered t...

Chromatic dispersion is a common problem to degrade the system resolution in optical coherence tomography (OCT). This study is to develop a deep learning network for automated dispersion compensation (ADC-Net) in OCT. The ADC-Net is based on a modified UNet architecture which employs an encoder-decoder pipeline. The input section encompasses partia...

Intrinsic optical signal (IOS) imaging of the retina, also termed as optoretinogram or optoretinography (ORG), promises a non-invasive method for the objective assessment of retinal function. By providing the unparalleled capability to differentiate individual retinal layers, functional optical coherence tomography (OCT) has been actively investiga...

Purpose: This study is to test the feasibility of optical coherence tomography (OCT) detection of photoreceptor abnormality and to verify the photoreceptor abnormality is rod predominated in early DR . Methods: OCT images were acquired from normal eyes, diabetic eyes with no diabetic retinopathy (NoDR) and mild NPDR. Quantitative features, inclu...

Early detection of diabetic retinopathy (DR) is an essential step to prevent vision losses. This study is to conduct comparative optical coherence tomography (OCT) and OCT-Angiography (OCTA) analysis, and to identify quantitative features for robust detection of early DR. Five quantitative OCT features were derived to analyze the outer retinal band...

Many eye diseases, such as diabetic retinopathy (DR) and retinopathy of prematurity (ROP), can cause abnormalities at both central and peripheral regions of the fundus. Therefore, a wide field fundus imaging is desirable for screening, diagnosis, and treatment evaluation of eye diseases. The traditional fundus imaging device which uses trans-pupill...

The purpose of this study is to use optical coherence tomography (OCT) to characterize the reflectance profiles of retinal blood vessels and to use these features for artery-vein classification in OCT angiography (OCTA). The retinal arteries and veins show unique features in the depth-resolved OCT. Both the upper and lower side of the retinal arter...

A wide-field fundus camera, which can selectively evaluate the retina and choroid, is desirable for better detection and treatment evaluation of eye diseases. Trans-palpebral illumination has been demonstrated for wide-field fundus photography, but its application for true-color retinal imaging is challenging due to the light efficiency delivered t...

Intrinsic optical signal (IOS) imaging of the retina, also termed as optoretinography (ORG), promises a noninvasive method for objective assessment of retinal function. By providing unparalleled capability to differentiate individual layers of the retina, functional optical coherence tomography (OCT) has been actively investigated for intrinsic sig...

The cornea is a highly specialized organ that relies on its mechanical stiffness to maintain its aspheric geometry and refractive power, and corneal diseases such as keratoconus have been linked to abnormal tissue stiffness and biomechanics. Dynamic optical coherence elastography (OCE) is a clinically promising non-contact and non-destructive imagi...

Chromatic dispersion is a common problem to degrade the system resolution in optical coherence tomography (OCT). This study is to develop a deep learning network for automated dispersion compensation (ADC-Net) in OCT. The ADC-Net is based on a redesigned UNet architecture which employs an encoder-decoder pipeline. The input section encompasses part...

This study is to characterize reflectance profiles of retinal blood vessels in optical coherence tomography (OCT), and to test the potential of using these vascular features to guide artery-vein classification in OCT angiography (OCTA) of the human retina. Depth-resolved OCT reveals unique features of retinal arteries and veins. Retinal arteries sh...

This study is to characterize spectral efficiency of trans-palpebral illumination, and to validate label-free multispectral imaging for nonmydriatic widefield examination of the chorioretinal vasculature in the living human eye.

This study is to characterize reflectance profiles of retinal blood vessels in optical coherence tomography (OCT), and to validate these vascular features to guide artery-vein classification in OCT angiography (OCTA) of human retina. Depth-resolved OCT reveals unique features of retinal arteries and veins. Retinal arteries show hyper-reflective bou...

Purpose: This study is to test the feasibility of optical coherence tomography (OCT) detection of photoreceptor abnormality and to verify the photoreceptor abnormality is rod predominated in early DR . Methods: OCT images were acquired from normal eyes, diabetic eyes with no diabetic retinopathy (NoDR) and mild DR. Quantitative features, including...

A portable, low cost, widefield fundus camera is essential for developing affordable tele-ophthalmology. However, conventional trans-pupillary illumination used in traditional fundus cameras limits the field of view (FOV) in a snapshot image, and frequently requires pharmacologically pupillary dilation for reliable examination of eye conditions. Th...

In this chapter, we summarize the state of the art of quantitative optical coherence tomography angiography (OCTA) features with technical rationale and describe potential clinical applications of quantitative OCTA analysis. In addition, we also discuss the artificial intelligence based applications demonstrated for OCTA disease classification, fea...

Abstract: Visual-angle has been used as the conventional unit to determine the field-of-view (FOV) in traditional fundus photography. Recently emerging usage of eye-angle as the unit in wide field fundus photography creates confusions about FOV interpretation in instrumentation design and clinical application. This study aims to systematically deri...

Optical coherence tomography angiography (OCTA) offers a noninvasive label-free solution for imaging retinal vasculatures at the capillary level resolution. In principle, improved resolution implies a better chance to reveal subtle microvascular distortions associated with eye diseases that are asymptomatic in early stages. However, massive screeni...

Significance: As one part of the central nervous system, the retina manifests neurovascular defects in Alzheimer’s disease (AD). Quantitative imaging of retinal neurovascular abnormalities may promise a new method for early diagnosis and treatment assessment of AD. Previous imaging studies of transgenic AD mouse models have been limited to the cent...

Visual-angle has been used as the conventional unit to determine the field-of-view (FOV) in traditional fundus photography. Recently emerging usage of eye-angle as the unit in wide field fundus photography creates confusions about FOV interpretation in instrumentation design and clinical application. This study is to systematically derive the relat...

By providing the sectioning capability to differentiate individual retinal layers, optical coherence tomography (OCT) is revolutionizing eye disease diagnosis and treatment evaluation. A better understanding of the hyper- and hypo-reflective bands in retinal OCT is essential for accurate interpretation of clinical outcomes. In this article, we summ...

Intrinsic optical signal (IOS) imaging promises a noninvasive method for objective assessment of retinal function. This study demonstrates concurrent optical coherence tomography (OCT) of amplitude-IOS and phase-IOS changes in human photoreceptors. A new procedure for differential-phase-mapping (DPM) is validated to enable depth-resolved phase-IOS...

A widefieldfundus examination is desirable for screening, diagnosis, and treatment evaluation of diabetic retinopathy (DR), retinopathy of prematurity (ROP), intraocular tumors and other eye diseases which can cause abnormalities at both central and peripheral region of the ocular fundus. The limited field of view (FOV) of traditional fundus camera...

Physiological dysfunction of diseased cells might occur prior to detectable morphological abnormalities such as retinal cell damage and thickness change. Functional assessment of photoreceptor physiology is essential for the early detection of eye diseases. It is desirable to develop a high-resolution method for objective assessment of photorecepto...

Early disease diagnosis and effective treatment assessment are crucial to prevent vision loss. Retinal arteries and veins can be affected differently by different eye diseases, e.g., arterial narrowing and venous beading in diabetic retinopathy (DR). Therefore, differential artery-vein (AV) analysis can provide valuable information for early diseas...

High-resolution ophthalmic imaging is imperative for detecting subtle changes of photoreceptor abnormality at the early stage of retinal diseases. However, optical resolution in retinal imaging is inherently limited by the low numerical aperture of the ocular optics. Virtually structured detection (VSD) has been demonstrated to break the diffractio...

Early detection of photoreceptor dysfunction is essential for preventing vision loss due to retinal degenerative diseases, such as age-related macular degeneration (AMD) and inherited retinal degenerations (IRDs). Functional intrinsic optical signal (IOS) imaging promises a high-resolution method for objective optoretinography (ORG). Stimulus-evoke...

The objective of this study is to verify the anatomic correlate of the second (2nd) outer retina band in optical coherence tomography (OCT), and to demonstrate the potential of using intrinsic optical signal (IOS) imaging for concurrent optoretinography (ORG) of phototransduction activation and energy metabolism in stimulus activated retinal photor...

Differential artery-vein (AV) analysis is essential for retinal study, disease detection, and treatment assessment. This study is to characterize vascular reflectance profiles and blood flow patterns of retinal artery and vein systems in optical coherence tomography (OCT) and OCT angiography (OCTA), and establish them as robust signatures for objec...

Functional mapping of photoreceptor physiology is important for better disease diagnosis and treatment assessment. Fast intrinsic optical signal (IOS), which arises before light-evoked pupillary response, promises a unique biomarker of photoreceptor physiology for objective optoretinography with high resolution. This study is to test the feasibilit...

Multispectral imaging (MSI) of the retina and choroid has increasing interest for better diagnosis and treatment evaluation of eye diseases. However, currently available MSI systems have a limited field of view (FOV) to evaluate the peripheral retina. This study is to validate trans-pars-planar illumination for a contact-mode ultra-widefield MSI sy...

Background: High resolution imaging is desirable for advanced study and clinical management of retinal diseases. However, spatial resolution of retinal imaging has been limited due to available numerical aperture and optical aberration of the ocular optics. This study is to develop and validate virtually structured detection (VSD) to surpass diffra...

Stimulus-evoked intrinsic optical signal (IOS), which occurs almost immediately after the onset of retinal stimulus has been observed in retinal photoreceptors, promises to be a unique biomarker for objective optoretinography (ORG) of photoreceptor function. We report here the first-time in vivo ORG detection of photoreceptor dysfunction due to ret...

This study is to demonstrate deep learning for automated artery-vein (AV) classification in optical coherence tomography angiography (OCTA). The AV-Net, a fully convolutional network (FCN) based on modified U-shaped CNN architecture, incorporates enface OCT and OCTA to differentiate arteries and veins. For the multi-modal training process, the enfa...

Purpose : To demonstrate the feasibility of using virtually structured detection (VSD) for super-resolution imaging of retinal photoreceptors in awake human. Methods : A line-scanning laser ophthalmoscopy was developed in conjunction with a high-speed CMOS camera to record the two-dimension (2D) line pattern pro les at a rate of 25,000 Hz to minimi...

Purpose : This study is to investigate stimulus-evoked intrinsic optical signal (IOS) changes in photoreceptor outer segment (OS) and inner segment (IS), and thus to demonstrate the potential of functional IOS imaging of phototransduction and metabolic integrity of retinal photoreceptor. Methods : A custom-designed optical coherence tomography (OCT...