1. Articles from Jianhua Wang

    1-24 of 72 1 2 3 »
    1. The effect of software versions on the measurement of retinal vascular densities using optical coherence tomography angiography

      The effect of software versions on the measurement of retinal vascular densities using optical coherence tomography angiography

      Background The goal of the study was to determine the effect of different software versions on the measurement of retinal vessel densities using optical coherence tomography angiography (OCTA) in normal subjects. Methods Thirty-two eyes of eighteen healthy subjects were imaged using two OCTA devices: the Optovue RTVue and the Zeiss Cirrus. The macular 3 × 3 mm scan protocol was used. The images acquired using the Optovue OCTA device were exported using two different software versions in the system and compared to the images acquired through the Zeiss OCTA. In addition, the Optovue OCTA images were exported after manual adjustment of ...

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    2. Role of optical coherence tomography angiography in the characterization of vascular network patterns of ocular surface squamous neoplasia

      Role of optical coherence tomography angiography in the characterization of vascular network patterns of ocular surface squamous neoplasia

      Purpose To visualize and quantify vascular networks in individuals with ocular surface squamous neoplasia (OSSN) through optical coherence tomography angiography (OCTA). Method Cross-sectional study of OSSN patients. Vascular networks were measured by OCTA in the epithelium and sub-epithelial space in the tumors, adjacent tissue, and in the contralateral eye. Vessel area density (VAD, percent of blood vessels within 2.14 mm 2 ), was calculated for each location. Total tumor density (TTD, percent of blood vessels within the entire tumor) was calculated. VAD was assessed separately for corneal and conjunctival locations and compared. Results Fifteen patients with OSSN were included. The ...

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    3. Quantitative analysis of conjunctival microvasculature imaged using optical coherence tomography angiography

      Quantitative analysis of conjunctival microvasculature imaged using optical coherence tomography angiography

      Background The goal was to quantitatively analyze the bulbar conjunctival microvascular density using optical coherence tomography angiography (OCTA) and compare it to the vessel density using functional slit-lamp biomicroscopy (FSLB). Methods Temporal bulbar conjunctiva of 20 eyes (10 healthy subjects) was imaged using both OCTA and FSLB. Image processing was performed including equalization, de-noising, thresholding, and skeletonization. The vessel density was measured by fractal analysis (box counting, Dbox) and pixel counting (%). Results Vessel density (Dbox) of the bulbar conjunctiva obtained using OCTA was 1.28 ± 0.01 Dbox, which was significantly lower than the result (1.32 ± 0.01 Dbox ...

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    4. Altered Macular Microvasculature in Mild Cognitive Impairment and Alzheimer Disease

      Altered Macular Microvasculature in Mild Cognitive Impairment and Alzheimer Disease

      Background: The goal of the present study was to analyze the macular microvacular network in mild cognitive impirment (MCI) and Alzheimer disease (AD). Methods: Twelve patients with AD and 19 patients with MCI were recruited together with 21 cognitively normal controls with a similar range of ages. Optical coherence tomography angiography was used to image the retinal microvascular network at the macular region, including retinal vascular network (RVN), superficial vascular plexus (SVP), and deep vascular plexus (DVP). Fractal analysis (box counting, D box ) representing the microvascular density was performed in different annular zones and quadrantal sectors. The macular ganglion cell ...

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    5. Long scan depth optical coherence tomography on imaging accommodation: impact of enhanced axial resolution, signal-to-noise ratio and speed

      Long scan depth optical coherence tomography on imaging accommodation: impact of enhanced axial resolution, signal-to-noise ratio and speed

      Background Spectral domain optical coherence tomography (SD-OCT) was a useful tool to study accommodation in human eye, but the maximum image depth is limited due to the decreased signal-to-noise ratio (SNR). In this study, improving optical resolutions, speeds and the SNR were achieved by custom built SD-OCT, and the evaluation of the impact of the improvement during accommodation was investigated. Methods Three systems with different spectrometer designs, including two Charge Coupled Device (CCD) cameras and one Complementary Metal-Oxide-Semiconductor Transistor (CMOS) camera, were tested. We measured the point spread functions of a mirror at different positions to obtain the axial resolution ...

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    6. Altered birefringence of peripapillary retinal nerve fiber layer in multiple sclerosis measured by polarization sensitive optical coherence tomography

      Altered birefringence of peripapillary retinal nerve fiber layer in multiple sclerosis measured by polarization sensitive optical coherence tomography

      Background The retina has been used to study the pathophysiology of multiple sclerosis (MS). Peripapillary retinal nerve fiber layer (pRNFL) thinning has been suggested as an ocular biomarker of neurodegeneration in MS. The goal of this project was to determine the birefringence of the pRNFL by measuring the fiber birefringence using polarization sensitive optical coherence tomography (PS-OCT). Methods Sixty-six MS patients without history of optic neuritis (age: 39.9 ± 11.0 yrs. old, 53 females and 13 males) and 66 age- and gender-matched normal controls (age: 40.7 ± 11.4 yrs. old) were recruited. Custom built PS-OCT was used to ...

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    7. Optical coherence tomography for ocular surface and corneal diseases: a review

      Optical coherence tomography for ocular surface and corneal diseases: a review

      The advent of optical coherence tomography (OCT) imaging has changed the way ophthalmologists image the ocular surface and anterior segment of the eye. Its ability to obtain dynamic, high and ultra-high resolution, cross-sectional images of the ocular surface and anterior segment in a noninvasive and rapid manner allows for ease of use. In this review, we focus on the use of anterior segment OCT, which provides an “optical biopsy” or in vivo imaging of various ocular surface and corneal pathologies, allowing the clinician to diagnose diseases otherwise not visualized by traditional methods. The utility of anterior segment OCT for various ...

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    8. Axial elongation measured by long scan depth optical coherence tomography during pilocarpine-induced accommodation in intraocular lens-implanted eyes

      Axial elongation measured by long scan depth optical coherence tomography during pilocarpine-induced accommodation in intraocular lens-implanted eyes

      We used an ultra-long scan depth optical coherence tomography (UL-OCT) system to investigate changes in axial biometry of pseudophakic eyes during pilocarpine- induced accommodation. The right eyes from 25 healthy subjects (age range 49 to 84 years) with an intraocular lens (IOL) were imaged twice in the non-accommodative and the accommodative states. A custom-built UL-OCT instrument imaged the whole eye. Then accommodation was induced by two drops of 0.5% pilocarpine hydrochloride separated by a 5-minute interval. Following the same protocol, images were acquired again 30 minutes after the first drop. The central corneal thickness (CCT), anterior chamber depth (ACD ...

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    9. Characterization of Soft Contact Lens Fitting Using Ultra-Long Scan Depth Optical Coherence Tomography

      Characterization of Soft Contact Lens Fitting Using Ultra-Long Scan Depth Optical Coherence Tomography

      Objectives . To evaluate the centration and movement of soft contact lenses and to verify the repeatability of two repeated measurements of the lens centration and movement using ultra-long scan depth optical coherence tomography (UL-OCT). Methods . A 1-day Acuvue® Define™ lens was tested on both eyes of 10 subjects (5 males and 5 females; mean age, 31.6 years). The centration and blink-induced movement of the contact lens were measured using UL-OCT at 5 min and 30 min after insertion. The measurements were repeated once at each checkpoint. Results . Good repeatability was found in the lens centration and movement between the ...

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    10. Role of high resolution optical coherence tomography in diagnosing ocular surface squamous neoplasia with coexisting ocular surface diseases

      Role of high resolution optical coherence tomography in diagnosing ocular surface squamous neoplasia with coexisting ocular surface diseases

      Purpose Coexistence of an ocular surface disease can mask the typical features of ocular surface squamous neoplasia (OSSN). The purpose of this study was to evaluate high resolution optical coherence tomography (HR-OCT) as an adjunct in the detection and differentiation of OSSN within coexisting ocular surface pathologies. Methods Retrospective study of 16 patients with ocular surface disease and lesions suspicious for OSSN that were evaluated with HR-OCT. HR-OCT images of the lesions were taken to look for evidence of OSSN. Biopsies were performed in all cases, and the HR-OCT findings were compared to the histological results. Results Of the 16 ...

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    11. The measurement repeatability using different partition methods of intraretinal tomographic thickness maps in healthy human subjects

      The measurement repeatability using different partition methods of intraretinal tomographic thickness maps in healthy human subjects

      Purpose: To determine the repeatability and profiles with different partition methods in intraretinal thickness layers in healthy human subjects, using optical coherence tomography (OCT). Methods: A custom-built ultrahigh-resolution OCT was used to acquire three-dimensional volume of the macula in 20 healthy subjects. The dataset was acquired twice using the macular cube 512×128 protocol in an area of 6×6 mm 2 centered on the fovea. Commercially available segmentation software (Orion™) was used to segment the dataset into thickness maps of six intraretinal layers. The coefficient of repeatability and intraclass coefficient of correlation (ICC) were analyzed using hemispheric zoning and ...

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    12. In vivo quantification of cochlin in glaucomatous DBA/2J mice using optical coherence tomography

      In vivo quantification of cochlin in glaucomatous DBA/2J mice using optical coherence tomography

      The expression of cochlin in the trabecular meshwork (TM) precedes the clinical glaucoma symptoms in DBA/2J mice. The ability to quantify cochlin in the local tissue (TM) offers potential diagnostic and prognostic values. We present two (spectroscopic and magnetomotive) optical coherence tomography (OCT) approaches for in vivo cochlin quantification in a periodic manner. The cochlin-antibody OCT signal remains stable for up to 24 hours as seen at 3.5 hours after injection allowing for repeated quantification in the living mouse eyes.

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    13. Ultra high resolution optical coherence tomography in Boston type I keratoprosthesis

      Ultra high resolution optical coherence tomography in Boston type I keratoprosthesis

      PURPOSE: To evaluate the anterior keratoprosthesis-cornea interface in eyes with Boston type I keratoprosthesis (Kpro). METHODS: In a prospective non-interventional study, patients with Boston type I Kpro underwent ultra-high resolution optical coherence tomography (UHR-OCT) evaluation. The images were used to measure and describe characteristics of the anterior keratoprosthesis-cornea interface, epithelial interaction at the keratoprosthesis edge and the keratoprosthesis-cornea interface gap. RESULTS: Ten patients including 4 male and 6 female subjects with different preoperative diagnoses, i.e. 8 multiple corneal graft failures and 2 immunological ocular surface diseases, were studied. Mean age was 62.1 ± 20.0 (range, 33.0-83.0 ...

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    14. Automatic Biometry of the Anterior Segment During Accommodation Imaged by Optical Coherence Tomography

      Automatic Biometry of the Anterior Segment During Accommodation Imaged by Optical Coherence Tomography

      Objective: To test accuracy and repeatability of a software algorithm that performs automatic biometry of the anterior segment of the human eye imaged with long scan depth optical coherence tomography (OCT). Methods: The ocular anterior segment imaging was performed with custom-built long scan depth OCT. An automatic software algorithm including boundary segmentation, image registration, and optical correction was developed for fast and reliable biometric measurements based on the OCT images. The boundary segmentation algorithm mainly used the gradient information of images and applied the shortest path search based on the dynamic programming to optimize the edge finding. The automatic algorithm ...

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    15. Vertical and Horizontal Corneal Epithelial Thickness Profile Using Ultra-High Resolution and Long Scan Depth Optical Coherence Tomography

      Vertical and Horizontal Corneal Epithelial Thickness Profile Using Ultra-High Resolution and Long Scan Depth Optical Coherence Tomography

      Purpose To determine the vertical and horizontal thickness profiles of the corneal epithelium in vivo using ultra-long scan depth and ultra-high resolution spectral domain optical coherence tomography (SD-OCT). Methods A SD-OCT was developed with an axial resolution of ~3.3 µm in tissue and an extended scan depth. Forty-two eyes of 21 subjects were imaged twice. The entire horizontal and vertical corneal epithelial thickness profiles were evaluated. The coefficient of repeatability (CoR) and intraclass correlation (ICC) of the tests and interobserver variability were analyzed. Results The full width of the horizontal epithelium was detected, whereas part of the superior epithelium ...

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    16. Measurement of wavefront aberrations and lens deformation in the accommodated eye with optical coherence tomography-equipped wavefront system

      Measurement of wavefront aberrations and lens deformation in the accommodated eye with optical coherence tomography-equipped wavefront system

      To quantitatively approach the relationship between optical changes in an accommodated eye and the geometrical deformation of its crystalline lens, a long scan-depth anterior segment OCT equipped wavefront sensor was developed and integrated with a Badal system. With this system, accommodation was stimulated up to 6.0D in the left eye and also measured in the same eye for three subjects. High correlations between the accommodative responses of refractive power and the radius of the anterior lens surface were found for the three subjects (r>0.98). The change in spherical aberration was also highly correlated with the change in ...

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    17. Agreement of Corneal Epithelial Profiles Produced by Automated Segmentation of SD-OCT Images Having Different Optical Resolutions

      Agreement of Corneal Epithelial Profiles Produced by Automated Segmentation of SD-OCT Images Having Different Optical Resolutions

      Objective: Using a custom-developed segmentation algorithm, agreement of corneal epithelial thickness profile measurements between two spectral domain optical coherence tomography (SD-OCT) systems was assessed. Methods: Eighteen left eyes (18 subjects; mean+/-standard deviation; age, 23.2+/-0.9 years) were imaged twice on nonconsecutive days by a custom-built ultra-high resolution OCT (UHR-OCT) system and a commercial RTVue OCT system. A segmentation algorithm based on axial gradient information and a shortest path search was developed to measure corneal epithelial thickness profiles from the SD-OCT images. Results: There was good correlation between the automated and manual segmentation positions of the epithelium. The ...

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    18. Whole eye axial biometry during accommodation using ultra-long scan depth optical coherence tomography

      Whole eye axial biometry during accommodation using ultra-long scan depth optical coherence tomography

      Purpose To investigate changes of whole eye axial biometry during accommodation using ultra-long scan depth optical coherence tomography (UL-OCT). Design Prospective, observational case series. Methods Twenty-one adult subjects were enrolled. Using UL-OCT, the left eye of each subject was imaged with relaxed (0 D) and accommodative stimuli (+6 D). Full eye biometry included central corneal thickness (CCT), anterior chamber depth (ACD), lens thickness, vitreous length and axial length (AL). Results During accommodation (+6 D), the axial biometry of the whole eye changed significantly. Compared to the rest state, ACD at the accommodative state decreased significantly from 3.128 ± 0.305 ...

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    19. Axial Biometry of the Entire Eye Using Ultra-Long Scan Depth Optical Coherence Tomography

      Axial Biometry of the Entire Eye Using Ultra-Long Scan Depth Optical Coherence Tomography

      Purpose To assess the repeatability of axial biometry of the entire eye using ultra-long scan depth optical coherence tomography (OCT) and to investigate the agreement with IOLMaster measurements (Carl Zeiss Meditec). Design Prospective, observational case series. Methods There were 37 adult subjects enrolled in group 1 and 12 adult subjects enrolled in group 2. Using ultra-long scan depth OCT, the left eyes of these groups were measured in 2 separate sessions. The images were processed by a manual method and custom-developed automatic software. A model eye was imaged for verification. The subjects in group 2 were imaged using ultra-long scan ...

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    20. Fully Automated Biometry of In Situ Intraocular Lenses Using Long Scan Depth Spectral-Domain Optical Coherence Tomography

      Fully Automated Biometry of In Situ Intraocular Lenses Using Long Scan Depth Spectral-Domain Optical Coherence Tomography

      Purpose: Spectral-domain optical coherence tomography (SD-OCT) was used to automatically measure accommodative biometric changes in the anterior segment of eyes implanted with an intraocular lens (IOL). The repeatability and reliability of the automated measurements were also evaluated. Methods: Long scan depth SD-OCT was used to image the anterior segment of eyes implanted with IOLs. A fully automated algorithm was used to detect the boundaries of the cornea and IOL and yielded the measurements. The results included anterior segment dimensions in IOL eyes and the deflection of the IOLs. Automated measurements were validated in vitro and compared with the manual results ...

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    21. Phacoemulsification Induced Transient Swelling of Corneal Descemet’s Endothelium Complex Imaged with Ultra-High Resolution Optical Coherence Tomography

      Phacoemulsification Induced Transient Swelling of Corneal Descemet’s Endothelium Complex Imaged with Ultra-High Resolution Optical Coherence Tomography

      Purpose Thickness changes of corneal sub-layers after phacoemulsification were investigated by spectral domain ultra-high resolution optical coherence tomography (UHR-OCT). Methods The corneas (n = 26) of 26 age-related cataract surgery patients were studied. UHR-OCT was used to evaluate the thickness of Descemet’s Endothelium Complex (DEC), stroma, Bowman’s layer, epithelium, and full cornea at the center (CCT) before, one day after, and one week after surgery. Non-contact specular microscopy measured CCT, endothelial cell density, and morphology. Results The DEC, stroma, Bowman’s layer, and epithelium were visualized by UHR-OCT. Before surgery, the DEC in all cases appeared as a translucent ...

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    22. Ultra High-Resolution Anterior Segment Optical Coherence Tomography in the Diagnosis and Management of Ocular Surface Squamous Neoplasia

      Ultra High-Resolution Anterior Segment Optical Coherence Tomography in the Diagnosis and Management of Ocular Surface Squamous Neoplasia

      The development of optical coherence tomography (OCT) technology has helped to usher in a new era of in vivo diagnostic imaging of the eye. The utilization of OCT for imaging of the anterior segment and ocular surface has evolved from time-domain devices to spectral-domain devices with greater penetrance and resolution, providing novel images of anterior segment pathology to assist in diagnosis and management of disease. Ocular surface squamous neoplasia (OSSN) is one such pathology that has proven demonstrable by certain anterior segment OCT machines, specifically the newer devices capable of performing ultra high-resolution OCT (UHR-OCT). Distinctive features of OSSN on ...

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    23. Ocular anterior segment biometry and high-order wavefront aberrations during accommodation

      Ocular anterior segment biometry and high-order wavefront aberrations during accommodation

      Purpose: To investigate the relationships between the ocular anterior segment biometry and the ocular high-order aberrations (HOAs) during accommodation by combined ultra-long scan depth optical coherence tomography (UL-OCT) and wavefront sensor. Methods: Thirty-five right eyes of young healthy subjects (21 women and 14 men; age: 25.6 ± 3.1 years; spherical equivalent refractive error: -0.41 ± 0.59 D) were enrolled. A custom-built UL-OCT and a wavefront sensor were combined. They were able to image the ocular anterior segment and to measure the HOAs during accommodation. The differences in the biometric dimensions and in the HOAs between the non-accommodative and ...

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    24. High resolution OCT quantitative analysis of the space between the IOL and the posterior capsule during the early cataract post-operative period

      High resolution OCT quantitative analysis of the space between the IOL and the posterior capsule during the early cataract post-operative period

      Purpose: To quantitatively characterize the space between the intraocular lens (IOL) and the posterior capsule (IOL-PC space) during the early post-phacoemulsification period, using high resolution optical coherence tomography (OCT). Methods: Thirty eyes of 30 patients who underwent phacoemulsification were recruited and randomly divided into two groups. Acrysof Natural IQ IOLs were implanted in one group (n = 15), and Adapt-AO IOLs were implanted into the other (n = 15). A custom built OCT instrument was used to image the IOL-PC space at 1 day, 1 week, and 1 month after surgery. Slit-lamp examination and auto refraction were performed at each visit. Results ...

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    1. (72 articles) Jianhua Wang
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    Dual channel dual focus optical coherence tomography for imaging accommodation of the eye SD-OCT with Prolonged Scan Depth for Imaging the Anterior Segment of the Eye Characterization of soft contact lens edge fitting using ultra-high resolution and ultra-long scan depth optical coherence tomography Diagnosis and Management of Conjunctival and Corneal Intraepithelial Neoplasia Using Ultra High-Resolution Optical Coherence Tomography Vitreous Seeding in Retinocytoma: Importance of Optical Coherence Tomography Utility of Spectral-Domain Optical Coherence Tomography in Differentiating Papilledema From Pseudopapilledema: A Prospective Longitudinal Study Visualizing and quantifying cutaneous microvascular reactivity in humans using optical coherence tomography: Impaired dilator function in diabetes Optical Coherence Tomography of Outer Retinal Hyper-Reflectivity, Neovascularization and Pigment in Type 2 Macular Telangiectasia Early Detection of Incipient Retinal Pigment Epithelium Atrophy Overlying Drusen with Fundus Autofluorescence vs. Spectral Domain Optical Coherence Tomography Association of ABO blood groups and non-culprit plaque characteristics in acute coronary syndrome: an optical coherence tomography study Don't be afraid of the dark - OCT angiography through a black intraocular lens Postdoc Opening at The Department of Health Technology at the Technical University of Denmark (DTU)