1. Articles from Chan Yun Kim

    1-24 of 40 1 2 »
    1. Relationship between N95 Amplitude of Pattern Electroretinogram and Optical Coherence Tomography Angiography in Open-Angle Glaucoma

      Relationship between N95 Amplitude of Pattern Electroretinogram and Optical Coherence Tomography Angiography in Open-Angle Glaucoma

      Purpose: The pattern electroretinogram (PERG) is useful to detect retinal ganglion cell (RGC) damage in patients with glaucoma. Optical coherence tomography angiography (OCTA) measures retinal vessel density (VD), which is known to be reduced in glaucoma. There may be correlations between parameters of the PERG and OCTA in open-angle glaucoma (OAG). Methods: In total, 95 eyes of 95 OAG patients and 102 eyes of 102 normal controls were included in this study. N35, P50, and N95 latency along with P50 and N95 amplitude were obtained using the PERG. Retinal VD was measured around the peripapillary and macular area according to ...

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    2. Evaluating anterior segment structure using anterior segment optical coherence tomography in malignant glaucoma after Ahmed valve implantation

      Evaluating anterior segment structure using anterior segment optical coherence tomography in malignant glaucoma after Ahmed valve implantation

      Rationale: Malignant glaucoma is a rare condition that can be associated with surgery for glaucoma. In the present case report, we describe a case of malignant glaucoma occurring a week after Ahmed valve implantation. The change in anterior segment structure was identified using anterior segment optical coherence tomography (AS-OCT). Patient concerns: The 86-year-old woman with pseudoexfoliation glaucoma underwent Ahmed valve implantation. A week later, the intraocular pressure (IOP) increased to 74 mm Hg. Diagnosis: The anterior chamber was totally collapsed with conjunctival injection and edematous cornea. Finally, the patient was diagnosed with malignant glaucoma. The structure of anterior chamber was ...

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    3. Effect of systemic blood pressure on optical coherence tomography angiography in glaucoma patients

      Effect of systemic blood pressure on optical coherence tomography angiography in glaucoma patients

      Background The association between retinal microvascular structure and glaucoma has been revealed in multiple studies using optical tomography angiography (OCTA), but limited information on the macular vessel density (mVD) in patients with glaucoma is available. In this study, we tried to identity the factors that affected macular VD (mVD) in glaucomatous eyes. Methods This retrospective cross-sectional study evaluated OCT and OCTA images from 92 eyes from 58 healthy subjects and 179 eyes from 103 glaucoma patients using the SD-OCT database from July 2017 to July 2018. Glaucomatous eyes were further divided into two groups according to history of disc haemorrhage ...

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    4. Effect of image quality fluctuations on the repeatability of thickness measurements in swept-source optical coherence tomography

      Effect of image quality fluctuations on the repeatability of thickness measurements in swept-source optical coherence tomography

      This study investigated the effect of image quality fluctuations on the repeatability of thickness measurements of the peripapillary retinal nerve fibre (PP-RNFL) and ganglion cell-inner plexiform (GC-IPL) layers using swept-source optical coherence tomography (SS-OCT). Three consecutive OCT scans each were performed on 56 healthy subject. Finally, 168 SS-OCT results were analysed. Based on the tertile values of the mean absolute difference of image quality score, all subjects were divided into the following three groups—low-(LIQD), moderate-(MIQD), and high-(HIQD) image quality score difference groups. A linear mixed model and intraclass correlation coefficients (ICCs) were used for analyses. Despite ...

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    5. Factors associated with macular vessel density measured by optical coherence tomography angiography in healthy and glaucomatous eyes

      Factors associated with macular vessel density measured by optical coherence tomography angiography in healthy and glaucomatous eyes

      Purpose To investigate factors associated with macular vessel density and to analyze their effects according to glaucoma stage. Study design Retrospective cross-sectional study. Methods A total of 72 healthy eyes and 147 open-angle glaucomatous eyes were studied. All eyes underwent optical coherence tomography and visual field examinations. Clinical variables were compared according to the glaucoma stage. Relationships between macular vessel density (mVD) and other variables were analyzed using linear regression and segmented analyses. Results Age ( P = 0.010) and signal strength ( P < 0.001) were associated with macular vessel density in healthy eyes. In glaucomatous eyes, age, signal strength, ganglion ...

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    6. Diagnostic ability of vessel density measured by spectral-domain optical coherence tomography angiography for glaucoma in patients with high myopia

      Diagnostic ability of vessel density measured by spectral-domain optical coherence tomography angiography for glaucoma in patients with high myopia

      Although early glaucoma detection is important to prevent visual loss due to disease progression, its clinical diagnosis in highly myopic eyes is still difficult. Many studies using optical coherence tomography (OCT) angiography (OCTA) reported decreased vessel density (VD) in glaucomatous eyes compared to normal eyes. We evaluated the diagnostic ability of peripapillary VD and macular VD measured by OCTA, comparing them with conventional valuables such as peripapillary retinal nerve fibre layer (RNFL) thickness and macular ganglion cell-inner plexiform layer (GCIPL) thickness measured by OCT. We also calculated the average VD ratio (VDR) (average outer macular VD/average inner macular VD ...

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    7. Nomogram Using Optical Coherence Tomography and Visual Field Parameters to Predict Brain Lesions in Patients with Bitemporal Hemianopia

      Nomogram Using Optical Coherence Tomography and Visual Field Parameters to Predict Brain Lesions in Patients with Bitemporal Hemianopia

      Purpose : This study aims to develop a nomogram to predict brain lesions in patients with complete or incomplete bitemporal hemianopia by combining results from optical coherence tomography (OCT) and visual field (VF) testing. Material and Methods : We reviewed the medical records of patients who underwent magnetic resonance imaging (MRI) to identify brain lesions due to bitemporal hemianopia between January 2010 and March 2017, retrospectively. The patients were divided into two groups based on MRI findings: brain-lesion (+) group that had brain lesions on MRI ( n = 63), and brain-lesion (-) group without brain lesions on MRI ( n = 16). We compared OCT and VF ...

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    8. Diagnostic Ability of Swept-Source and Spectral-Domain Optical Coherence Tomography for Glaucoma

      Diagnostic Ability of Swept-Source and Spectral-Domain Optical Coherence Tomography for Glaucoma

      Purpose To compare the diagnostic abilities of swept-source optical coherence tomography (OCT) [Deep Range Imaging OCT-1 (DRI-OCT)] and spectral-domain OCT (Cirrus HD-OCT) for glaucoma in Korean adults. Materials and Methods This retrospective study involved measuring peripapillary retinal nerve fiber layer (PP-RNFL) thickness, full macular thickness, and ganglion cell-inner plexiform layer (GC-IPL) thickness on two different OCT systems. We used three-dimensional optic disc scanning of DRI-OCT and included 12 clock-hour sectors for measurement of the PP-RNFL. Areas under receiver operating characteristic curves (AUCs) were calculated and compared to determine how well each system could distinguish control and glaucomatous patients. Results Ninety-one ...

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    9. Comparison of Central Corneal Thickness Measured by Swept-source Optical Coherence Tomography and Ultrasound Pachymetry

      Comparison of Central Corneal Thickness Measured by Swept-source Optical Coherence Tomography and Ultrasound Pachymetry

      Purpose To analyze and compare ultrasound pachymetry (USP) with a more recently adopted device, the intra ocular lens (IOL) master 700, which are both used to measure central corneal thickness. Methods The central corneal thickness was measured in 24 eyes of 12 glaucoma patients and in 83 eyes of 42 normal patients. First, the IOL master 700 was used to measure the central corneal thickness, followed by measurements taken using USP later. The results were analyzed using a paired t -test. We analyzed the agreement and the correlations between the two test devices by using Bland-Altman plots and the Pearson ...

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    10. Thickness in Ganglion Cell-Inner Plexiform Layer on Spectral-Domain Optical Coherence Tomography after Cataract Surgery

      Thickness in Ganglion Cell-Inner Plexiform Layer on Spectral-Domain Optical Coherence Tomography after Cataract Surgery

      Purpose To assess changes in ganglion cell-inner plexiform layer (GCIPL) thickness after cataract surgery using spectral-domain optical coherence tomography (OCT). Methods Forty-three eyes of 33 patients, who underwent cataract surgery were imaged with spectral-domain OCT before and after surgery to measure peripapillary retinal nerve fiber layer (RNFL) and GCIPL thickness, signal strength (SS), quadrant, 12 clock-hour RNFL thickness and sectoral GCIPL thickness. Results The postoperative SS, RNFL and GCIPL thickness were higher than before surgery ( p < 0.05). Multivariate analysis showed that endothelial cell count and preoperative SS were significantly correlated with SS changes in RNFL parameters and preoperative SS ...

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    11. Influence of epiretinal membrane on the measurement of peripapillary retinal nerve fibre layer thickness using spectral-domain coherence tomography

      Influence of epiretinal membrane on the measurement of peripapillary retinal nerve fibre layer thickness using spectral-domain coherence tomography

      Background/aims To investigate the effect of epiretinal membrane (ERM) on peripapillary retinal nerve fibre layer (RNFL) thickness measurements using spectral-domain optical coherence tomography (Spectralis; Heidelberg Engineering). Methods A total of 134 patients with idiopathic ERM and 63 healthy controls were included in this observational comparative study. We categorised ERMs into three severity grades, based on retinal appearance in macular scans. All eyes with ERM were classified into two groups; those involving the peripapillary scan area (ERM+pp, n=68 eyes) and not involving the peripapillary scan area (ERM−pp, n=66 eyes) using the macular disc scan. Peripapillary RNFL ...

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    12. Relationship between Peripapillary Retinal Nerve Fiber Layer Thickness Measured by Optical Coherence Tomography and Visual Field Severity Indices

      Relationship between Peripapillary Retinal Nerve Fiber Layer Thickness Measured by Optical Coherence Tomography and Visual Field Severity Indices

      Purpose Though there are many reports regarding the structure-function relationship in glaucoma, they are too complicated to apply to the routine clinical setting. The aim of this study was to investigate the direct relationship between peripapillary retinal nerve fiber layer (RNFL) thickness measured by optical coherence tomography (OCT) and visual field (VF) severity indices computed by standard automated perimetry. Methods This cross-sectional comparative study included 104 glaucomatous patients and 59 healthy subjects. Peripapillary RNFL thickness was measured by spectral domain (SD) and time domain (TD) OCTs. Four glaucoma VF severity indices, including mean deviation (MD), pattern standard deviation (PSD), Collaborative ...

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    13. Use of optical coherence tomography to predict visual outcome in parachiasmal meningioma

      Use of optical coherence tomography to predict visual outcome in parachiasmal meningioma

      OBJECT The authors investigated the value of retinal nerve fiber layer (RNFL) thickness in predicting visual outcome after surgery for parachiasmal meningioma. METHODS Forty-nine eyes of 25 patients who underwent craniotomy and resection of a parachiasmal meningioma were analyzed retrospectively. Visual parameters including visual field (VF) (recorded as the mean deviation [MD]), visual acuity (VA), and RNFL thickness (via optical coherence tomography) were measured before and 1 week, 6 months, and 1 year after surgery. Postoperative visual outcome was compared among the patients with a thin or normal RNFL. A separate analysis of data pertaining to 22 eyes of 13 ...

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    14. Pattern of Macular Ganglion Cell-Inner Plexiform Layer Defect Generated by Spectral-Domain OCT in Glaucoma Patients and Normal Subjects

      Pattern of Macular Ganglion Cell-Inner Plexiform Layer Defect Generated by Spectral-Domain OCT in Glaucoma Patients and Normal Subjects

      Purpose: To elucidate patterns of macular ganglion cell-inner plexiform layer (GCIPL) defects by Cirrus optical coherence tomography (OCT) and examine the spatial relationship between GCIPL defect and visual field (VF) defect patterns. Methods: A total of 116 eyes of 116 normal subjects and 111 eyes of 111 glaucoma patients were included. The 227 study subjects underwent Cirrus OCT imaging in macular cube mode and reliable standard VF testing. Two ophthalmologists blindly classified GCIPL defect patterns and VF defects. The frequency distribution of GCIPL defect patterns and spatial relationships between GCIPL defects and VF defects were investigated. Results: GCIPL defect patterns ...

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    15. Frequency, Type and Cause of Artifacts in Swept-Source and Cirrus HD Optical Coherence Tomography in Cases of Glaucoma and Suspected Glaucoma

      Frequency, Type and Cause of Artifacts in Swept-Source and Cirrus HD Optical Coherence Tomography in Cases of Glaucoma and Suspected Glaucoma

      Purpose : To evaluate and compare the frequency , type and cause of imaging artifacts incurred when using swept - source optical coherence tomography (SS OCT) and Cirrus HD OCT in the same patients on the same day. Materials and methods : From left eye OCT results of 72 patients, disc area and macular area data could be compared between the two types of OCT. For each scan, the final printout report and source data were examined. For comparison between the two types of OCT, only source image data were used because of differences in the final printout report format. Results : There were no ...

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    16. Visual Fields and OCT Role in Diagnosis of Glaucoma

      Visual Fields and OCT Role in Diagnosis of Glaucoma

      Purpose: To evaluate the clinical performance of visual field (VF) tests and optical coherence tomography (OCT) in diagnosing glaucoma. Methods: One hundred sets of disc photographs, red-free fundus photographs, VF tests, and OCT images were presented progressively to seven ophthalmologists. Each set was provided in three steps: (1) the disc and red-free fundus photographs were shown first; (2) then, VF tests were also provided; and (3) finally, the OCT results were provided. The same process was repeated on another day. Kappa statistics were used to assess the intraobserver and interobserver agreement, as well as the agreement with the reference standard ...

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    17. A Hierarchical Cluster Analysis of Normal-Tension Glaucoma Using Spectral-Domain Optical Coherence Tomography Parameters

      A Hierarchical Cluster Analysis of Normal-Tension Glaucoma Using Spectral-Domain Optical Coherence Tomography Parameters

      Purpose: Normal-tension glaucoma (NTG) is a heterogenous disease, and there is still controversy about subclassifications of this disorder. On the basis of spectral-domain optical coherence tomography (SD-OCT), we subdivided NTG with hierarchical cluster analysis using optic nerve head (ONH) parameters and retinal nerve fiber layer (RNFL) thicknesses. Patients and Methods: A total of 200 eyes of 200 NTG patients between March 2011 and June 2012 underwent SD-OCT scans to measure ONH parameters and RNFL thicknesses. We classified NTG into homogenous subgroups based on these variables using a hierarchical cluster analysis, and compared clusters to evaluate diverse NTG characteristics. Results: Three ...

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    18. Relationship between Visual Acuity and Retinal Structures Measured by Spectral Domain Optical Coherence Tomography in Patients with Open Angle Glaucoma

      Relationship between Visual Acuity and Retinal Structures Measured by Spectral Domain Optical Coherence Tomography in Patients with Open Angle Glaucoma

      Purpose: To assess the relationship between retinal structures measured by spectral-domain optical coherence tomography (OCT) and visual acuity in open-angle glaucoma (OAG) patients. Methods: In this cross-sectional observational study, 186 eyes from 186 OAG patients were included. The participants underwent RTVue OCT for measurement of circumpapillary retinal nerve fiber layer (cpRNFL) thickness and macular ganglion cell complex (mGCC) thickness. The correlations between best-corrected visual acuity (BCVA) and OCT parameters were evaluated using Pearson's partial correlation test and regression analysis. Receiver operating characteristic (ROC) curve analysis was performed to obtain a cutoff value for OCT parameters in detecting decreased visual ...

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    19. A hierarchical cluster analysis of primary angle closure classification using anterior segment optical coherence tomography parameters

      A hierarchical cluster analysis of primary angle closure classification using anterior segment optical coherence tomography parameters

      Purpose: To investigate the possibility of classifying angle closure eyes in terms of features provided by anterior segment optical coherence tomography (AS OCT). Methods: Angle closure (Primary angle closure (PAC) or PAC glaucoma (PACG)) eyes diagnosed by gonioscopy were imaged using AS OCT under the same lighting conditions. Anterior chamber depth (ACD), anterior chamber width (ACW), iris cross-sectional area (IA), iris thickness at 750 µm from the scleral spur (IT750), iris curvature (IC), lens vault (LV), and anterior chamber area (ACA) were determined using Image J software (ver. 1.44, National Institutes of Health). A hierarchical cluster analysis using Ward ...

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    20. A Formula to Predict Spectral Domain Optical Coherence Tomography (OCT) Retinal Nerve Fiber Layer Measurements Based on Time Domain OCT Measurements

      A Formula to Predict Spectral Domain Optical Coherence Tomography (OCT) Retinal Nerve Fiber Layer Measurements Based on Time Domain OCT Measurements
      Purpose To establish and validate a formula to predict spectral domain (SD)-optical coherence tomography (OCT) retinal nerve fiber layer (RNFL) thickness from time domain (TD)-OCT RNFL measurements and other factors. Methods SD-OCT and TD-OCT scans were obtained on the same day from healthy participants and patients with glaucoma. Univariate and multivariate linear regression relationships were analyzed to convert average Stratus TD-OCT measurements to average Cirrus SD-OCT measurements. Additional baseline characteristics included age, sex, intraocular pressure, central corneal thickness, spherical equivalent, anterior chamber depth, optic disc area, visual field (VF) mean deviation, and pattern standard deviation. The formula was ...
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    21. Macula assessment using optical coherence tomography for glaucoma diagnosis

      Macula assessment using optical coherence tomography for glaucoma diagnosis
      Optical coherence tomography (OCT) is an interferometry-based imaging modality that generates high-resolution cross-sectional images of the retina. Circumpapillary retinal nerve fibre layer (cpRNFL) and optic disc assessments are the mainstay of glaucomatous structural measurements. However, because these measurements are not always available or precise, it would be useful to have another reliable indicator. The macula has been suggested as an alternative scanning location for glaucoma diagnosis. Using time-domain (TD) OCT, macular measurements have been shown to provide good glaucoma diagnostic capabilities. Performance of cpRNFL measurement was generally superior to macular assessment. However, macular measurement showed better glaucoma diagnostic performance and ...
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    22. Agreement of retinal nerve fiber layer color codes between Stratus and Cirrus OCT according to glaucoma severity

      Agreement of retinal nerve fiber layer color codes between Stratus and Cirrus OCT according to glaucoma severity

      Purpose: To assess the agreement of retinal nerve fiber layer (RNFL) color codes between Stratus and Cirrus optical coherence tomography (OCT) according to the glaucoma severity. Methods: A total of 184 eyes from 144 subjects with glaucoma and 40 normal subjects were analyzed. Glaucoma was categorized into three subgroups according to mean deviation of visual field. The agreement of RNFL color code according to the glaucoma severity was assessed using Cohen's kappa value. Red or yellow color codes were defined as abnormal results while green or white were defined as normal. Disagreement frequency of abnormal color code displayed by ...

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    23. Influence of Blue Light-filtering Intraocular Lenses on Retinal Nerve Fiber Layer Measurements by Spectral-domain Optical Coherence Tomography

      Influence of Blue Light-filtering Intraocular Lenses on Retinal Nerve Fiber Layer Measurements by Spectral-domain Optical Coherence Tomography
      Purpose: The purpose of this study was to assess the influence of blue light-filtering intraocular lenses (IOL) on peripapillary retinal nerve fiber layer (RNFL) thickness measurements by spectral-domain (SD) optical coherence tomography (OCT). Methods: This prospective study included 50 eyes of 50 patients. Patients were randomly assigned to receive either a blue light-filtering IOL (acrysof IQ (SN60WF) [Alcon]) or a clear IOL (Tecnis (Z9003) [AMO]). The peripapillary RNFL thickness was measured using a Cirrus SD OCT before and 8 weeks after cataract surgery. Perioperative differences in RNFL thickness measurements and signal strengths (SS) were evaluated and compared in both IOL ...
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    24. Comparison of the Optic Nerve Imaging by Time-Domain Optical Coherence Tomography and Fourier-Domain Optical Coherence Tomography in Distinguishing Normal Eyes From Those With Glaucoma

      Comparison of the Optic Nerve Imaging by Time-Domain Optical Coherence Tomography and Fourier-Domain Optical Coherence Tomography in Distinguishing Normal Eyes From Those With Glaucoma
      Purpose: To assess agreement in cup-to-disc ratio (CDR) estimation between stereoscopic optic disc photography, time-domain optical coherence tomography (OCT), and Fourier-domain OCT, and to compare the discriminating ability of optic nerve head (ONH) parameters by time-domain OCT and Fourier-domain OCT for glaucoma detection. Methods: Participants underwent stereoscopic photography, Stratus OCT (fast optic disc scan), and RTVue-100 (nerve head mapping), at the same visit. Vertical and horizontal CDRs (VCDR and HCDR) from stereoscopic photography were determined by averaging the results from 2 independent glaucoma specialists. VCDR, HCDR, disc area, cup area, rim area, and cup-to-disc area ratio were acquired from the ...
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    1. (38 articles) Chan Yun Kim
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