1. Articles from Chan Kee Park

    1-17 of 17
    1. Microvasculature Recovery Detected Using Optical Coherence Tomography Angiography and the Rate of Visual Field Progression After Glaucoma Surgery

      Microvasculature Recovery Detected Using Optical Coherence Tomography Angiography and the Rate of Visual Field Progression After Glaucoma Surgery

      Purpose: We evaluated microvascular changes using optical coherence tomography angiography (OCT-A) in glaucoma patients who underwent glaucoma surgery. Methods: The macula and optic nerve head were imaged using an OCT-A device at one day before surgery and at one week, one month, three months, and six months after surgery. Measurements of vessel density (VD) were made in the intradisc region and macula, and the area of the foveal avascular zone (FAZ) was measured in both superficial and deep vascular layers. A mean deviation (MD) slope value of < -1.0 decibel/y was considered to be indicative of VF progression. Results ...

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    2. Determinants of vessel defects in superficial and deep vascular layers in normal-tension glaucoma using optical coherence tomography angiography

      Determinants of vessel defects in superficial and deep vascular layers in normal-tension glaucoma using optical coherence tomography angiography

      We investigated the characteristics of localized vessel density defects (VD) either in the deep or superficial vascular layer of normal-tension glaucoma patients using optical coherence tomography angiography (OCTA). In this retrospective, cross-sectional study, 74 eyes with localized retinal nerve fiber layer (RNFL) defect were included. The relationships between the widths of the VD in the superficial and deep layer and ocular factors were evaluated. Eyes with greater deep VD were significantly older (P = 0.023). The IOP measured at OCTA exam was significantly related to the width of the deep VD (P = 0.009). By contrast, average ganglion cell inner ...

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    3. Impact of Posterior Sclera on Glaucoma Progression in Treated Myopic Normal-Tension Glaucoma Using Reconstructed Optical Coherence Tomographic Images

      Impact of Posterior Sclera on Glaucoma Progression in Treated Myopic Normal-Tension Glaucoma Using Reconstructed Optical Coherence Tomographic Images

      Purpose : To investigate factors associated with visual field (VF) progression in treated myopic normal-tension glaucoma (NTG) using a novel posterior sclera reconstruction method involving swept-source optical coherence tomography (OCT). Methods : Fifty-six myopic patients on ocular hypotensive therapy with the diagnose NTG had five or more VF tests during a period of 72.63 ± 20.46 months in clinical follow-up. Glaucomatous VF progression was decided by the standards of Early Manifest Glaucoma Trial criteria. Coronally reconstructed OCT images were used to obtain the position of the deepest point of the eye (DPE), and parameterized the distance (Disc-DPE distance), depth (Disc–DPE ...

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    4. Association Between Parapapillary Choroidal Vessel Density Measured With Optical Coherence Tomography Angiography and Future Visual Field Progression in Patients With Glaucoma

      Association Between Parapapillary Choroidal Vessel Density Measured With Optical Coherence Tomography Angiography and Future Visual Field Progression in Patients With Glaucoma

      Importance Investigating the vascular risk factors of glaucoma progression is important to individualize treatment; however, few studies have investigated these factors because the available methods have proven insufficient to evaluate the vascular features of patients with glaucoma. Recently, the advent of optical coherence tomography angiography (OCT-A) allowed both qualitative and quantitative microvascular data to be obtained, to in turn evaluate the perfusion status of different retinal layers. Objective To determine whether baseline parapapillary choroidal vessel density (VD) as measured by OCT-A was associated with future glaucoma progression. Design, Setting, and Participants A prospective, observational, comparative study was conducted at Seoul ...

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    5. Detecting the Progression of Normal Tension Glaucoma: A Comparison of Perimetry, Optic Coherence Tomography, and Heidelberg Retinal Tomography

      Detecting the Progression of Normal Tension Glaucoma: A Comparison of Perimetry, Optic Coherence Tomography, and Heidelberg Retinal Tomography

      Purpose We compared the abilities of Stratus optical coherence tomography (OCT), Heidelberg retinal tomography (HRT) and standard automated perimetry (SAP) to detect the progression of normal tension glaucoma (NTG) in patients whose eyes displayed localized retinal nerve fiber layer (RNFL) defect enlargements. Methods One hundred four NTG patients were selected who met the selection criteria: a localized RNFL defect visible on red-free fundus photography, a minimum of five years of follow-up, and a minimum of five reliable SAP, Stratus OCT and HRT tests. Tests which detected progression at any visit during the 5-year follow-up were identified, and patients were further ...

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    6. Intereye Comparison of Cirrus OCT in Early Glaucoma Diagnosis and Detecting Photographic Retinal Nerve Fiber Layer Abnormalities

      Intereye Comparison of Cirrus OCT in Early Glaucoma Diagnosis and Detecting Photographic Retinal Nerve Fiber Layer Abnormalities

      Purpose: To compare the ability of various maps constructed using Cirrus optical coherence tomography (OCT), including the "intereye comparison" derived from the temporal-superior-inferior-nasal-temporal (TSNIT) map, in terms of glaucoma diagnosis and detection of RNFL defects identified in red-free fundus photographs. Methods: This cross-sectional study was conducted on a total of 131 open-angle glaucoma patients with early-stage visual field defects (mean deviation ≤ -6.0 dB) and 56 normal controls. Intereye differences were identified on TSNIT maps constructed by comparing the RNFL thickness curves of both eyes of individual patients and a separation of the RNFL thickness curves of either eye (by ...

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    7. The effect of myopic optic disc tilt on measurement of spectral-domain optical coherence tomography parameters

      The effect of myopic optic disc tilt on measurement of spectral-domain optical coherence tomography parameters

      Background To compare the spectral-domain optical coherence tomography (SD-OCT) parameters, including ganglion cell-inner plexiform layer (GCIPL) thickness, retinal nerve fibre layer (RNFL) thickness and optic nerve head (ONH) parameters between glaucomatous eyes with myopic tilted optic disc and non-tilted optic disc, and to investigate the effect of optic disc tilt on the diagnostic performance of these parameters. Methods The study included 82 patients with glaucoma and 41 refraction-matched normal subjects. The OCT parameters and their diagnostic abilities were compared between the non-tilted disc group (N=41) and tilted disc group (N=41). Results The ONH parameters in the tilted disc ...

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    8. Glaucoma Diagnostic Accuracy of Optical Coherence Tomography Parameters in Early Glaucoma with Different Types of Optic Disc Damage

      Glaucoma Diagnostic Accuracy of Optical Coherence Tomography Parameters in Early Glaucoma with Different Types of Optic Disc Damage

      Purpose To compare the initial visual field (VF) defect pattern and the spectral-domain optical coherence tomography (OCT) parameters and investigate the effects of distinct types of optic disc damage on the diagnostic performance of these OCT parameters in early glaucoma. Design Retrospective, observational study. Participants A total of 138 control eyes and 160 eyes with early glaucoma were enrolled. The glaucomatous eyes were subdivided into 4 groups according to the type of optic disc damage: focal ischemic (FI) group, myopic (MY) group, senile sclerotic (SS) group, and generalized enlargement (GE) group. Methods The values of total deviation (TD) maps were ...

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    9. Analysis of Macular and Peripapillary Choroidal Thickness in Glaucoma Patients by Enhanced Depth Imaging Optical Coherence Tomography

      Analysis of Macular and Peripapillary Choroidal Thickness in Glaucoma Patients by Enhanced Depth Imaging Optical Coherence Tomography

      Background/Aim: To compare the macular and peripapillary choroidal thickness between normal and glaucoma eyes and find out factors related to choroidal thickness using enhanced depth imaging (EDI) of Heidelberg Spectralis SD-OCT. Study Design: Cross-sectional transverse study. Methods: A total of 108 glaucoma patients and 48 healthy controls were included in the analysis. Choroidal thickness was measured from 6 mm length radial B-scans at the macular and the optic nerve head by EDI OCT. Choroidal thickness was compared between normal controls, normal tension glaucoma (NTG) patients, and primary open-angle glaucoma (POAG) patients. Factors related to choroidal thickness were analyzed by ...

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    10. Measurement of Scleral Thickness using Swept-Source Optical Coherence Tomography in Open-Angle Glaucoma Patients with Myopia

      Measurement of Scleral Thickness using Swept-Source Optical Coherence Tomography in Open-Angle Glaucoma Patients with Myopia

      Purpose To use swept-source optical coherence tomography (OCT) to image the posterior sclera at the posterior pole and around the optic nerve head (ONH), and measure the subfoveal scleral thickness and laminar thickness to evaluate the relationship between the measured thicknesses and ocular parameters. Design Prospective, cross-sectional design. Methods One hundred and twelve glaucoma patients and 46 controls with axial length more than 26 mm were enrolled. Swept-source OCT images were obtained to capture the subfoveal and ONH region. Subfoveal scleral thickness and laminar thickness were measured from obtained B-scan images. To verify the reproducibility of the measurement, intraclass correlation ...

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    11. Imaging the Posterior Segment of the Eye using Swept-Source Optical Coherence Tomography in Myopic Glaucoma Eyes: Comparison with Enhanced-Depth Imaging

      Imaging the Posterior Segment of the Eye using Swept-Source Optical Coherence Tomography in Myopic Glaucoma Eyes: Comparison with Enhanced-Depth Imaging

      Purpose To compare the detection rates of identifying the posterior border of the sclera and lamina cribrosa and measurement reproducibility of scleral and laminar thicknesses using enhanced depth imaging (EDI) of Heidelberg Spectralis optical coherence tomography (OCT) and swept-source OCT. Design Cross-sectional design. Methods Both EDI-OCT and swept-source OCT images were obtained in 32 myopic glaucoma patients. Subfoveal choroidal, subfoveal scleral, and central laminar thicknesses were measured from obtained B-scan images. Each measurement was performed at three locations by two masked observers. The detection rates and measurement reproducibility were evaluated from selected B-scans. Results The posterior border of the sclera ...

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    12. Visualization of Blebs Using Anterior-Segment Optical Coherence Tomography after Glaucoma Drainage Implant Surgery

      Visualization of Blebs Using Anterior-Segment Optical Coherence Tomography after Glaucoma Drainage Implant Surgery

      Objective The current study investigated the internal structure of blebs using anterior-segment optical coherence tomography (AS-OCT) in patients who had undergone Ahmed glaucoma valve (AGV) (New World Medical Inc, Rancho Cucamonga, CA) implantation and compared the differences between successful and failed surgeries. Design Cross-sectional, observational study. Participants A total of 76 patients who had undergone AGV implantation. Methods The blebs after AGV implantation were examined using AS-OCT. The relationship between intraocular pressure (IOP) or the number of glaucoma medications and intrableb parameters was evaluated. Success was defined as IOP ≤21 mmHg with a maximum of 2 glaucoma medications, and the ...

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    13. Diagnostic Capability of Lamina Cribrosa Thickness by Enhanced Depth Imaging and Factors Affecting Thickness in Patients with Glaucoma

      Diagnostic Capability of Lamina Cribrosa Thickness by Enhanced Depth Imaging and Factors Affecting Thickness in Patients with Glaucoma

      Objective To determine the diagnostic ability of laminar thickness obtained using enhanced depth imaging (EDI) of the Heidelberg Spectralis optical coherence tomography (OCT) system (Heidelberg Engineering, Heidelberg, Germany) and the factors related to laminar thickness in patients with glaucoma. Design Evaluation of a diagnostic test. Participants A total of 144 patients with glaucoma (68 with primary open-angle glaucoma [POAG], 76 with normal-tension glaucoma [NTG]), and 65 healthy controls. Methods All patients underwent retinal nerve fiber layer (RNFL) thickness and optic nerve head (ONH) scanning with the Spectralis OCT system. Mean laminar thickness was defined at the center of the mid-superior ...

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    14. Glaucoma diagnosis optic disc analysis comparing Cirrus spectral domain optical coherence tomography and Heidelberg retina tomograph II

      Glaucoma diagnosis optic disc analysis comparing Cirrus spectral domain optical coherence tomography and Heidelberg retina tomograph II

      Purpose To evaluate the diagnostic ability of optic nerve head parameters, measured by Cirrus spectral domain optical coherence tomography (SD OCT) and Heidelberg retina tomograph II (HRT II) to detect concomitant glaucoma. Methods Cirrus OCT and HRT examinations of 62 eyes of 62 patients (32 with no perimetric glaucoma and 30 with concomitant perimetric glaucoma) evaluated between August 2010 and December 2010 were retrospectively analyzed and compared with regard to the optic disc morphometric parameter, disc area, rim area, cup-to-disc ratio (CDR), and cup volume. Receiver operating characteristic curves were constructed for the parameters and areas under the curves (AUCs ...

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    15. The Effects of Peripapillary Atrophy on the Diagnostic Ability of Stratus and Cirrus OCT in the Analysis of Optic Nerve Head Parameters and the Disc Size

      The Effects of Peripapillary Atrophy on the Diagnostic Ability of Stratus and Cirrus OCT in the Analysis of Optic Nerve Head Parameters and the Disc Size

      Purpose: We compared the diagnostic ability of Stratus and Cirrus optical coherence tomography (OCT) in optic nerve head (ONH) analysis, and examined the effects of optic disc size and peripapillary atrophy (PPA) on their diagnostic capacity. Methods: Stratus and Cirrus OCT were performed in 28 control and 78 glaucomatous eyes. ONH parameters and diagnostic capacity calculated from the area under the receiver operating characteristics curve (AUC) were compared between the two modalities. Glaucomatous eyes were classified by optic disc size and the presence/absence of PPA, and their AUCs were compared. Results: Rim area (AUC, 0.936) and rim volume ...

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    16. Enhanced Depth Imaging Detects Lamina Cribrosa Thickness Differences in Normal Tension Glaucoma and Primary Open-Angle Glaucoma

      Enhanced Depth Imaging Detects Lamina Cribrosa Thickness Differences in Normal Tension Glaucoma and Primary Open-Angle Glaucoma
      Objective: To confirm the advantages of the enhanced depth imaging (EDI) mode over the standard mode of the Heidelberg Spectralis spectral domain optical coherence tomography (SD-OCT) for imaging of the lamina cribrosa, and to compare laminar thicknesses of various glaucoma types with or without disc hemorrhage in a similar state of visual field loss. Design Cross-sectional, case-control design. Participants We included 137 glaucoma patients and 49 healthy controls. Methods Optic nerve head B-scans were obtained by both the standard and EDI modes of the Spectralis OCT. Laminar thickness was measured at the center of mid-superior, central, and mid-inferior horizontal B-scans ...
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    17. Early diabetic changes in the nerve fibre layer at the macula detected by spectral domain optical coherence tomography

      Early diabetic changes in the nerve fibre layer at the macula detected by spectral domain optical coherence tomography
      Aim To detect early nerve fibre layer (NFL) changes around the optic disc and macula in diabetic patients using Cirrus HD-optical coherence tomography (OCT). Methods Forty normal patients without any optic nerve or retinal disease, 37 patients with diabetes with no diabetic retinopathy (NDR) and 89 patients with diabetic retinopathy (DR) of differing severity were enrolled. The NFL thickness around the optic disc was measured using Cirrus HD-OCT. The NFL thickness at the macula was also determined by scanning the macula with the optic disc scanning technique. Results The NFL thickness around the optic disc differed statistically among all groups ...
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    1-17 of 17
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    Early diabetic changes in the nerve fibre layer at the macula detected by spectral domain optical coherence tomography Enhanced Depth Imaging Detects Lamina Cribrosa Thickness Differences in Normal Tension Glaucoma and Primary Open-Angle Glaucoma The Effects of Peripapillary Atrophy on the Diagnostic Ability of Stratus and Cirrus OCT in the Analysis of Optic Nerve Head Parameters and the Disc Size Glaucoma diagnosis optic disc analysis comparing Cirrus spectral domain optical coherence tomography and Heidelberg retina tomograph II Visualization of Blebs Using Anterior-Segment Optical Coherence Tomography after Glaucoma Drainage Implant Surgery Diagnostic Capability of Lamina Cribrosa Thickness by Enhanced Depth Imaging and Factors Affecting Thickness in Patients with Glaucoma Imaging the Posterior Segment of the Eye using Swept-Source Optical Coherence Tomography in Myopic Glaucoma Eyes: Comparison with Enhanced-Depth Imaging Measurement of Scleral Thickness using Swept-Source Optical Coherence Tomography in Open-Angle Glaucoma Patients with Myopia Analysis of Macular and Peripapillary Choroidal Thickness in Glaucoma Patients by Enhanced Depth Imaging Optical Coherence Tomography The effect of myopic optic disc tilt on measurement of spectral-domain optical coherence tomography parameters Comparison of Anterior Segment Measurements with a New Multifunctional Unit and Five Other Devices Efficacy of Notal Vision Home OCT demonstrated by a series of scientific and clinical work