Publications (27)73.72 Total impact
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Article: Intraocular pressure reduction with topical medications and progression of normal-tension glaucoma: a 12-year mean follow-up study.
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ABSTRACT: Purpose: To investigate whether the amount of intraocular pressure (IOP) reduction with topical medications is associated with the progression of normal-tension glaucoma (NTG) and to identify risk factors for NTG progression. Methods: The medical records of 121 eyes of 121 NTG patients, who were treated with topical medications for more than 7 years, were reviewed. NTG progression was defined by either structural (optic disc or retinal nerve fibre layer) or functional (visual field) deterioration. Patients were divided into tertile groups according to the percentage IOP reduction from baseline, and the cumulative probability of NTG progression between upper and lower tertile group was compared using Kaplan-Meier survival analysis. Multivariate analysis with Cox's proportional hazard model was performed to identify the hazard ratio (HR) of clinical factors for NTG progression. Results: The average follow-up period was 12.2 years, and 56 of 121 eyes (46.3%) showed the NTG progression. Kaplan-Meier analysis revealed that upper tertile group (percentage IOP reduction >22.1%) showed a greater cumulative probability of non-progression than lower tertile group (percentage IOP reduction < 13.3%; p = 0.012). Multivariate Cox's proportional hazard model indicated that percentage reduction of IOP (HR = 0.964; p = 0.007) and the occurrence of disc haemorrhage (HR = 2.410; p = 0.008) were significantly associated with NTG progression. Conclusions: The amount of IOP reduction using topical medications was related to NTG progression, and lower percentage reduction in IOP was a consistent risk factor for progression.Acta ophthalmologica 02/2013; · 2.44 Impact Factor -
Article: Diagnostic Ability of Spectral-domain Versus Time-domain Optical Coherence Tomography in Preperimetric Glaucoma.
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ABSTRACT: PURPOSE:: To evaluate and compare the diagnostic abilities of the speckle noise-reduced spectral-domain optical coherence tomography (SD-OCT; Spectralis OCT) and time-domain optical coherence tomography (TD-OCT; Stratus OCT) to detect localized retinal nerve fiber layer (RNFL) defects in patients with preperimetric open-angle glaucoma. METHODS:: Thirty-five eyes of 35 preperimetric glaucoma patients with localized RNFL defects and 72 normal control eyes were scanned using SD-OCT and TD-OCT. Areas under the receiver-operating characteristic curves (AUROCs), and the sensitivity and specificity for detecting localized RNFL defects based on the internal normative database of each device were calculated and compared. RESULTS:: The AUROC for the best parameter from SD-OCT (inferotemporal sector, AUROC=0.940) was significantly higher than that of TD-OCT (7 o'clock sector, AUROC=0.881; P=0.009). The sensitivity of the SD-OCT parameters ranged from 18.9% to 83.8% and that of the TD-OCT parameters ranged from 5.4% to 54.1%, with the criterion of abnormal at the 5% level. The highest sensitivity of the SD-OCT was found with the temporal-superior-nasal-inferior-temporal thickness graph abnormal at the 5% level, which had a specificity of 90.3%. On the basis of temporal-superior-nasal-inferior-temporal thickness graphs, SD-OCT was more sensitive (P=0.001) for detection of preperimetric RNFL defects than TD-OCT at a comparable specificity (P=0.227). CONCLUSIONS:: Speckle noise-reduced SD-OCT is better able to detect preperimetric localized RNFL defect(s) than TD-OCT.Journal of glaucoma 01/2013; · 1.74 Impact Factor -
Article: Optic disc rim area to retinal nerve fiber layer thickness correlation: comparison of diabetic and normal tension glaucoma eyes.
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ABSTRACT: PURPOSE: To compare the correlation between optic disc rim area and retinal nerve fiber layer thickness (rim-RNFL correlation) in diabetic eyes with non-progressive RNFL defects and normal tension glaucoma (NTG) eyes. METHODS: Seventy-three eyes of 73 patients with preperimetric or early NTG and 25 eyes of 25 type II diabetes patients with a non-progressive RNFL defect for ≥5 years were enrolled in this retrospective cohort study. Rim areas and RNFL thicknesses were measured by Heidelberg retina tomography (HRT II) and by optical coherence tomography (Cirrus OCT), in global and 12 clock-hour parameters. Diabetic eyes were evaluated whether they were above the 95 % prediction interval (PI) for the rim-RNFL correlation of NTG. RESULTS: A significant linear rim-RNFL correlation was observed in NTG eyes globally and at all clock-hours, except in the 4 and 9 o'clock areas, (0.08 < r (2) < 0.56, P < 0.05). Eighty-four percent of the diabetic eyes were above the 95 % PI of the rim-RNFL correlation of NTG in ≥2 clock-hours, as compared with 36 % of the eyes in the global parameter. CONCLUSIONS: The eyes of diabetic patients with non-progressive RNFL were well-differentiated from NTG eyes by the rim-RNFL correlation.Japanese Journal of Ophthalmology 11/2012; · 0.92 Impact Factor -
Article: Correlation between retinal nerve fiber layer thickness and visual field sensitivity: diffuse atrophy imaging study.
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ABSTRACT: To identify the correlation between retinal nerve fiber layer (RNFL) thickness and visual field sensitivity in healthy eyes with preperimetric and perimetric glaucoma and to estimate the functional RNFL loss in eyes with pre-perimetric glaucoma. One hundred and two eyes with glaucoma and diffuse RNFL atrophy and 102 healthy eyes were enrolled. The correlation between optical coherence tomography (OCT)-measured RNFL thickness of the superior (clock-hour segments 10, 11, 12, 1, 2, and 3) and inferior (clock-hour segments 5, 6, 7, and 8) area and the average total deviations of the inferior and superior hemifields in standard automated perimetry (SAP) were evaluated using the simple linear model, respectively. The OCT-measured RNFL thickness was assumed to comprise functional and residual thicknesses; the residual thickness was calculated from the simple linear model and the eyes with severe diffuse RNFL atrophy. Functional RNFL thickness was compared between groups. Twenty-seven eyes had preperimetric and 75 eyes had perimetric glaucoma. The coefficient of determination (R(2)) of the simple linear model was 0.71 to 0.77 for the correlation between RNFL thickness and total deviation of SAP. The estimated residual thickness was 50.4 to 56.5 μm. On comparison with normal eyes, eyes with preperimetric glaucoma were estimated to have 37% to 41% functional RNFL loss. The correlation between RNFL thickness and SAP sensitivity was well explained by the simple linear model. Approximately 40% loss of the functional RNFL was found in preperimetric glaucoma.Ophthalmic Surgery Lasers and Imaging 11/2012; 43(6):S75-82. · 0.62 Impact Factor -
Article: Hong's grading for evaluating anterior chamber angle width.
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ABSTRACT: PURPOSE: To compare Hong's grading method with anterior segment optical coherence tomography (AS-OCT), gonioscopy, and the dark-room prone-position test (DRPT) for evaluating anterior chamber width. METHODS: The anterior chamber angle was graded using Hong's grading method, and Hong's angle width was calculated from the arctangent of Hong's grades. The correlation between Hong's angle width and AS-OCT parameters was analyzed. The area under the receiver operating characteristic curve (AUC) for Hong's grading method when discriminating between narrow and open angles as determined by gonioscopy was calculated. Correlation analysis was performed between Hong's angle width and intraocular pressure (IOP) changes determined by DRPT. RESULTS: A total of 60 subjects were enrolled. Of these subjects, 53.5 % had a narrow angle. Hong's angle width correlated significantly with the AS-OCT parameters (r = 0.562-0.719, P < 0.01). A Bland-Altman plot showed relatively good agreement between Hong's angle width and the angle width obtained by AS-OCT. The ability of Hong's grading method to discriminate between open and narrow angles was good (AUC = 0.868, 95 % CI 0.756-0.942). A significant linear correlation was found between Hong's angle width and IOP change determined by DRPT (r = -0.761, P < 0.01). CONCLUSIONS: Hong's grading method is useful for detecting narrow angles. Hong's grading correlated well with AS-OCT parameters and DRPT.Japanese Journal of Ophthalmology 09/2012; · 0.92 Impact Factor -
Article: Detection of localized retinal nerve fiber layer defects with posterior pole asymmetry analysis of spectral domain optical coherence tomography.
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ABSTRACT: To investigate the diagnostic ability of posterior pole asymmetry analysis (PPAA) with spectral domain optical coherence tomography (SD-OCT) for detecting localized retinal nerve fiber layer defects (RNFLD). Eighty-four open-angle glaucoma subjects (84 eyes) with localized, wedge-shape RNFLDs by red-free RNFL photography and 122 eyes of healthy subjects were enrolled. The subjects were examined by SD-OCT to obtain circumpapillary RNFL (cpRNFL) thickness as well as PPAA. The PPAA provides a corresponding cell to cell comparison between hemispheres within the central 20° and presents the difference using gray scale. Area under the receiver operating characteristic curve (AUROC) was calculated. The sensitivity and specificity of PPAA to detect glaucoma with the localized defects were also examined using various criteria; two consecutive black cells (criterion A), three consecutive black cells (criterion B), and four consecutive black cells (criterion C). An AUROC of PPAA based on the number of black cells was 0.958 ± 0.013. The sensitivity and specificity of PPAA were 95.2% and 81.1% for criterion A, 83.3% and 92.6% for criterion B, and 69.0% and 98.4% for criterion C, respectively. The sensitivity and specificity of the cpRNFL thickness were 85.7% and 95.1%, respectively. SD-OCT PPAA detects localized RNFLDs with high sensitivity and specificity, which are comparable to the cpRNFL thickness profile of OCT. These findings suggest that the PPAA can be complementary to other tests for diagnosing glaucoma in patients with localized RNFLDs.Investigative ophthalmology & visual science 05/2012; 53(8):4347-53. · 3.43 Impact Factor -
Article: Unilateral pulmonary edema: a rare initial presentation of cardiogenic shock due to acute myocardial infarction.
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ABSTRACT: Cardiogenic unilateral pulmonary edema (UPE) is a rare clinical entity that is often misdiagnosed at first. Most cases of cardiogenic UPE occur in the right upper lobe and are caused by severe mitral regurgitation (MR). We present an unusual case of right-sided UPE in a patient with cardiogenic shock due to acute myocardial infarction (AMI) without severe MR. The patient was successfully treated by percutaneous coronary intervention and medical therapy for heart failure. Follow-up chest Radiography showed complete resolution of the UPE. This case reminds us that AMI can present as UPE even in patients without severe MR or any preexisting pulmonary disease affecting the vasculature or parenchyma of the lung.Journal of Korean medical science 02/2012; 27(2):211-4. · 0.84 Impact Factor -
Article: Three-dimensional evaluation of the lamina cribrosa using spectral-domain optical coherence tomography in glaucoma.
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ABSTRACT: To introduce a novel, digital, three-dimensional (3D) reconstruction of the optic nerve head (ONH) and to use this method to evaluate the 3D configuration of the lamina cribrosa (LC) in patients with primary open-angle glaucoma. Optic discs of 137 eyes of 137 patients with open-angle glaucoma were scanned with enhanced depth-imaging spectral domain-optical coherence tomography (SD-OCT). 3D images of the ONH were then reconstructed from B-scan images using maximum intensity projection (MIP) and texture-based volume rendering (VRT). The performance of the threshold segmentation by MIP and VRT was assessed by comparing the distance of the anterior LC surface from the reference line set at the Bruch's membrane opening level (LC depth) measured within both of the 3D images and the B-scan images. The LC configuration could be evaluated three dimensionally in ∼95% of patients scanned with enhanced depth-imaging SD-OCT. The mean LC depth was 559.50 ± 151.98, 558.97 ± 152.39, and 560.22 ± 152.26 μm in B-scan, MIP, and VRT images, respectively. There were excellent agreements between the values (intraclass correlation coefficient = 1.000 between MIP and B-scan, and 0.999 between VRT and B-scan). The configuration of the LC varied considerably among individual glaucoma patients. This method provides measurable 3D images of the LC that enable comprehensive evaluation of the LC configuration. This technique should facilitate the investigation of the LC in glaucomatous eyes.Investigative ophthalmology & visual science 12/2011; 53(1):198-204. · 3.43 Impact Factor -
Article: Diagnostic accuracy of OCT with a normative database to detect diffuse retinal nerve fiber layer atrophy: Diffuse Atrophy Imaging Study.
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ABSTRACT: To investigate the diagnostic accuracy of Stratus optical coherence tomography (OCT) with its internal normative database to detect diffuse retinal nerve fiber layer (RNFL) atrophy in glaucoma subjects. One hundred two eyes of 102 glaucoma patients with diffuse RNFL atrophy and 102 healthy eyes of 102 age-matched subjects were enrolled in the Diffuse Atrophy Imaging Study. Two experienced observers graded RNFL photographs of diffuse RNFL atrophy eyes using a four-level grading system. The diagnostic performances for detecting diffuse RNFL atrophy were examined according to visual field results and RNFL photograph grading. Using a criterion of abnormal at the <5% level, the overall sensitivity of the Stratus OCT parameters ranged from 61.5% to 84.5%, and the overall specificity ranged from 90.2% to 99.0%. For mild, moderate, and severe diffuse RNFL atrophy, the superior quadrant had a sensitivity of 41.0%, 83.3%, and 100.0%, respectively, and the inferior quadrant had a sensitivity of 35.0%, 88.5%, and 100.0%, respectively. The highest likelihood ratios were obtained at the 11 and 12 o'clock sectors for superior RNFL and the 6 and 7 o'clock sectors for inferior RNFL. OCT with a normative database can detect diffuse RNFL atrophy with moderate sensitivity and high specificity. Because the sensitivity of Stratus OCT is closely related to the degree of diffuse RNFL atrophy and the visual field results, OCT with an internal normative database should be evaluated with prudence, especially in the early stage of glaucoma with diffuse RNFL atrophy.Investigative ophthalmology & visual science 06/2011; 52(9):6074-80. · 3.43 Impact Factor -
Article: Visualization of the lamina cribrosa using enhanced depth imaging spectral-domain optical coherence tomography.
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ABSTRACT: To investigate whether the enhanced depth imaging technique (EDI) may improve the visualization of the lamina cribrosa using spectral-domain optical coherence tomography (SD-OCT). Prospective observational case series. Images of the optic nerve were obtained in 10 normal subjects, 7 glaucoma suspects, and 18 glaucoma patients by positioning an SD-OCT in the usual fashion, as well as close enough to the eye to obtain an inverted representation of the fundus (EDI). In addition to these single line scans, approximately 65 sections were obtained within a 10 × 15-degree rectangle covering the optic nerve head using EDI. The "depth of signal" was measured as the distance from the optic cup surface and the point where the signal ended in both single line scan images. Compared to the image obtained with the SD-OCT used in the usual fashion, images obtained with EDI provided larger depth of signal (728.04 ± 124.20 vs 368.79 ± 75.15 μm, P < .001) below the optic cup surface and better image contrast from the deep optic nerve; this facilitated the discrimination of the lamina cribrosa. In the en face image, the lamina cribrosa was visualized as a highly reflective plate containing multiple pores that corresponded with the color fundus photographs. Using EDI SD-OCT, the full-thickness lamina cribrosa was clearly visualized in all eyes examined. This technique should facilitate the investigation on the lamina cribrosa in glaucoma, and may provide additional insight into the pathogenesis of glaucomatous optic neuropathy.American journal of ophthalmology 05/2011; 152(1):87-95.e1. · 3.83 Impact Factor -
Article: Clock hour-based analysis of the correlation between optic disc rim area and retinal nerve fiber layer thickness.
American journal of ophthalmology 05/2011; 151(5):915-6. · 3.83 Impact Factor -
Article: Comparison of the correlations between optic disc rim area and retinal nerve fiber layer thickness in glaucoma and nonarteritic anterior ischemic optic neuropathy.
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ABSTRACT: To test whether comparison of the correlation between optic disc rim area and retinal nerve fiber layer thickness (rim-RNFL correlation) can differentiate eyes with nonarteritic anterior ischemic optic neuropathy (NAION) from eyes with open-angle glaucoma (OAG). Prospective cross-sectional study. One hundred and thirteen eyes with OAG and 22 with NAION were included in this study. The rim-RNFL correlation in OAG eyes was analyzed in global and 12-clock-hour parameters using rim areas determined by Heidelberg retina tomography (HRT II) and RNFL thicknesses determined by optical coherence tomography (Cirrus OCT). The eyes with NAION were determined whether to be out of the 95% prediction interval (PI) for the rim-RNFL correlation of OAG in global and clock-hour parameters. A significant linear rim-RNFL correlation was observed in global and all clock-hour sectors, except the 3-, 4-, and 9-o'clock sectors, in OAG (0.045 < r(2) < 0.64, P < .05, respectively). All eyes with NAION were outside the 95% PI of the rim-RNFL correlation of OAG in at least 1 clock-hour sector in terms of clock-hour parameters, as compared with 63.6% of eyes in terms of global parameter. All NAION eyes (n = 21) with 7- or 11-o'clock involvement had a rim-RNFL correlation outside the 95% PI of OAG for corresponding clock-hour sectors. By comparison of the rim-RNFL correlation, eyes with NAION were found to be well differentiated from OAG eyes, especially in clock-hour sectors. It might be an objective approach to discriminate NAION from OAG.American journal of ophthalmology 02/2011; 151(2):277-86.e1. · 3.83 Impact Factor -
Article: Investigation of the association between Helicobacter pylori infection and normal tension glaucoma.
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ABSTRACT: To investigate whether Helicobacter pylori infection is associated with normal tension glaucoma (NTG). One hundred consecutive NTG patients (group 1) from an outpatient glaucoma clinic were enrolled. Medical records of the 88 control participants (control 1) of the outpatient clinic, and 104 NTG patients (group 2) and 1116 healthy controls (control 2) (1220 subjects in total) from a primary health care center were reviewed retrospectively to compare the results. Serum samples from all subjects were analyzed for the presence of H. pylori-specific immunoglobulin G antibodies using ELISA. The distributions of serologic H. pylori test results of the NTG patients and control subjects were compared, and possible associations between clinical phenotypes and positive serologic results were assessed. Bilaterality of NTG patients was also analyzed. NTG patients had significantly more positive serologic results than did the healthy controls. There were significant differences between group 1 and control 1 patients (P = 0.020; odds ratio [OR], 2.05), group 1 and control 2 patients (P = 0.016; OR, 1.73), and group 2 and control 2 patients (P = 0.008; OR, 1.83). However, no significant association was found between clinical characteristics and a positive serologic result for H. pylori in NTG patients. This study suggests that H. pylori infection may be associated with an increased risk for NTG. H. pylori may play a role in the development or progression of NTG as a secondary aggravating factor because of the coexistence of other main causes or it may be the primary cause.Investigative ophthalmology & visual science 02/2011; 52(2):665-8. · 3.43 Impact Factor -
Article: A case of cytomegalovirus colitis in an immunocompetent hemodialysis patient.
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ABSTRACT: Symptomatic cytomegalovirus (CMV) infection in immunocompetent patients has traditionally been considered to have a benign and self-limited course. Moreover, current concept is that CMV infection in immunocompetent patients does not require treatment. However, recent studies reveal that CMV infection in immunocompetent patient with clinical manifestation is not a rare condition as thought previously. Here, we report a case of CMV colitis, which occurred in an immunocompetent hemodialysis patient who neither had HIV infection nor had medication that could cause immunosuppression. Our case revealed that the conservative treatment was not enough, and the administration of ganciclovir was essential for improving the disease course.Hemodialysis International 01/2011; 15(2):297-300. · 1.54 Impact Factor -
Article: β-Zone parapapillary atrophy and the rate of retinal nerve fiber layer thinning in glaucoma.
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ABSTRACT: To evaluate whether β-zone parapapillary atrophy (PPA) is associated with the rate of retinal nerve fiber layer (RNFL) thickness change as assessed by trend-based analysis using time-domain optical coherence tomography (OCT). This retrospective cohort study included 202 glaucomatous eyes that were observed for ≥3 years with serial OCTs and stereo disc photographs. Subjects were divided into two groups according to the presence (n = 144) or absence of β-zone PPA (n = 58). The rates of progressive thinning in global, quadrant, and clock-hour OCT RNFL thicknesses were determined using linear regression and compared between groups. Logistic regression analysis was used to determine the factors associated with the rate of global RNFL thinning. The mean rate for global RNFL thinning over time was -1.03 ± 1.50 μm/year. Eyes with β-zone PPA showed a significantly faster rate of RNFL thinning than did eyes without β-zone PPA in the inferior quadrant and 7 o'clock sector (values of P < 0.0029). Multivariate analysis showed significant influence of the presence of β-zone PPA and the percentage increase in the PPA to disc area ratio during the follow-up on the rate of OCT RNFL thinning (odds ratio [OR], 3.314, P = 0.007; OR, 2.894, P = 0.003, respectively). Glaucomatous eyes with β-zone PPA are at increased risk for progressive RNFL thinning.Investigative ophthalmology & visual science 01/2011; 52(7):4422-7. · 3.43 Impact Factor -
Article: Trend-based analysis of retinal nerve fiber layer thickness measured by optical coherence tomography in eyes with localized nerve fiber layer defects.
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ABSTRACT: To evaluate the rate of change in retinal nerve fiber layer (RNFL) thickness measured by optical coherence tomography (OCT) in eyes with stable and progressive localized RNFL defects and to investigate, in a trend-based approach, the diagnostic capability of OCT in the detection of progressive RNFL thinning. The study included 153 glaucomatous eyes with localized RNFL defects. The patients were divided into nonprogressors (n = 77) and progressors (n = 76) on the basis of an evaluation of serial red-free photographs. The rates of progressive thinning in global, quadrant, and clock-hour OCT RNFL thicknesses were determined, by linear regression, and were compared between groups. Areas under receiver operating characteristic curves and sensitivities at fixed specificities were calculated for each parameter. The rate of progressive RNFL thinning was significantly faster in progressors than in nonprogressors globally; in the inferior quadrant; in the 10, 11, 6, and 7 o'clock sectors; and in the affected quadrant and clock-hour sector thicknesses (all P ≤ 0.001). The rate of RNFL thinning in affected clock-hour sectors had the highest ability to discriminate between stable and progressive RNFL thinning with a sensitivity of 62% (95% confidence interval, 50%-73%) at a specificity ≥80%. Agreement between OCT and red-free photography was strongest when the criterion of -3.6 μm/year with P < 0.1 was used for each clock hour. The rate of OCT RNFL thinning was significantly greater in patients with progressive localized RNFL defects than in those with stable localized defects. The data suggest that trend-based analysis of OCT RNFL thickness may be useful in glaucoma progression analysis and may complement other diagnostic tests.Investigative ophthalmology & visual science 11/2010; 52(2):1138-44. · 3.43 Impact Factor -
Article: Quantitative assessment of diffuse retinal nerve fiber layer atrophy using optical coherence tomography: diffuse atrophy imaging study.
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ABSTRACT: To evaluate quantitatively the degree of diffuse retinal nerve fiber layer (RNFL) atrophy using Stratus optical coherence tomography (OCT). Prospective, cross-sectional study. One hundred two eyes of 102 patients with diffuse RNFL atrophy and 102 healthy eyes of 102 age-matched subjects were enrolled in the Diffuse Atrophy Imaging Study. Two experienced observers graded RNFL photographs of diffuse RNFL atrophy eyes using a previously reported standardized protocol with a 4-level grading system. Readings were taken from the superior and inferior RNFL areas. The OCT-measured RNFL thickness parameters were compared among normal eyes and diffuse atrophy subgroups. Area under the receiver operating characteristic curves (AROCs) was calculated for various OCT RNFL parameters. Average and segmental (4 quadrants and 12 clock-hours) OCT-measured RNFL thicknesses and AROCs for various OCT parameters. For superior and inferior RNFL areas, diffuse atrophy grading by 2 observers agreed in 82.5% and 83.3% of cases, respectively, with a substantial agreement (kappa value = 0.760 [P < 0.001] and 0.777 [P < 0.001]). Significant differences were observed in RNFL thickness among normal and all diffuse atrophy subgroups, especially in the 7 and 11 o'clock sectors (P < 0.0001). The OCT RNFL thickness measurements decreased with increasing severity of RNFL damage. The 7 and 11 o'clock sectors showed the highest AROCs for discrimination of mild RNFL atrophy from normal eyes (0.972 and 0.979, respectively). The OCT RNFL thickness parameters showed excellent quantitative correlation with the degree of diffuse RNFL atrophy. Our results suggest that Stratus OCT may serve as a useful adjunct in accurately and objectively assessing the degree of diffuse RNFL atrophy.Ophthalmology 10/2010; 117(10):1946-52. · 5.45 Impact Factor -
Article: Reproducibility of retinal nerve fiber thickness measurements using the test-retest function of spectral OCT/SLO in normal and glaucomatous eyes.
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ABSTRACT: To evaluate the reproducibility of retinal nerve fiber layer (RNFL) thickness measurements in normal and glaucoma patients using the spectral optical coherence tomography (OCT)/scanning laser ophthalmosope (SLO). One experienced operator measured peripapillary RNFL thickness 3 times in succession in 98 normal participants and 79 glaucoma patients by using the test-retest function of the spectral OCT/SLO. The intraclass correlation coefficient (ICC), coefficient of variation, and test-retest variability (TRV) were analyzed for the mean RNFL thickness, and the RNFL thickness in each quadrant and at each clock-hour, in randomly selected eyes. The correlation coefficient was calculated between the TRV and the mean RNFL thickness, and between the TRV and the mean deviation of the Humphrey visual field. The ICC for mean RNFL thickness was 0.988 in the normal group and 0.993 in the glaucoma group. The ICC for RNFL thickness in all quadrants and clock-hours in both normal and glaucoma patients ranged from 0.951 to 0.992. The coefficient of variation was between 1.9% and 5.0% in the normal group and between 2.0% and 5.3% in the glaucoma group. The TRV was between 4.3 and 11.5 μm in the normal group and between 3.8 and 10.0 μm in the glaucoma group. The TRV showed no correlation with the mean RNFL thickness or the mean deviation (Pearson r>0.15, P>0.2). Spectral OCT/SLO equipped with a test-retest function showed excellent reproducibility with regard to RNFL thickness measurements. The severity of glaucoma did not affect the reproducibility. These findings suggest that spectral OCT/SLO fulfills one of the basic premises for the diagnosis and progression analysis of glaucoma.Journal of glaucoma 02/2010; 19(9):637-42. · 1.74 Impact Factor -
Article: Shifting pH optimum of Bacillus circulans xylanase based on molecular modeling.
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ABSTRACT: Although hydrolases are used in several industrial processes, its industrial applications have some limitations in specific cases since some industrial processes are carried out at pH value which is different from optimum pH of the enzyme. Alkaline side optimum pH of hydrolases is always desirable, and it is proved difficult to achieve that by mutation only. Hence, molecular modeling was applied to select the promising mutants. The changes in electrostatic potential, which was calculated using Delphi, were compared to the changes in pH optimum of four hydolases and their mutants. The results showed that the change in electrostatic potential can be used as an indicator for selecting relevant candidates of mutation. Bacillus circulans xylanase was selected as a model system, and the promising mutants were picked up by the molecular modeling. Q167M and R73V, had a higher pH optimum than the wild type, while K175Q had a similar pH-activity profile of the wild type.Journal of Biotechnology 03/2008; 133(3):294-300. · 3.05 Impact Factor -
Article: Mutation of non-conserved amino acids surrounding catalytic site to shift pH optimum of Bacillus circulans xylanase
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ABSTRACT: Improvement of enzyme function by engineering pH dependence of enzymatic activity is of importance for industrial application of Bacillus circulans xylanases. Target mutation sites were selected by structural alignment between B. circulans xylanase and other xylanases having different pH optima. We selected non-conserved mutant sites within 8 ˚A from the catalytic residues, to see whether these residues have some role in modulating pKas of the catalytic residues.We hypothesized that the non-conserved residues which may not have any role in enzyme catalysis might perturb pKas of the catalytic residues. Change in pKa of a titratable group due to change in electrostatic potential of a mutation was calculated and the change in pH optimum was predicted from the change in pKa of the catalytic residues. Our strategy is proved to be useful in selection of promising mutants to shift the pH optimum of the xylanases towards desired side.Journal of Molecular Catalysis B Enzymatic 01/2008; 55:130-136. · 2.73 Impact Factor
Top co-authors
Top Journals
Institutions
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2013
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Seoul National University Bundang Hospital
- Department of Ophthalmology
Seoul, Seoul, South Korea
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2004–2012
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Seoul National University Hospital
Seoul, Seoul, South Korea
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2011
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Kwandong University
Seoul, Seoul, South Korea -
Catholic University of Korea
- Department of Internal Medicine
Seoul, Seoul, South Korea
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