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author:("Hong, samia")
1.  The Neuroprotective Effect of Maltol against Oxidative Stress on Rat Retinal Neuronal Cells 
Purpose
Maltol (3-hydroxy-2-methyl-4-pyrone), formed by the thermal degradation of starch, is found in coffee, caramelized foods, and Korean ginseng root. This study investigated whether maltol could rescue neuroretinal cells from oxidative injury in vitro.
Methods
R28 cells, which are rat embryonic precursor neuroretinal cells, were exposed to hydrogen peroxide (H2O2, 0.0 to 1.5 mM) as an oxidative stress with or without maltol (0.0 to 1.0 mM). Cell viability was monitored with the lactate dehydrogenase assay and apoptosis was examined by the terminal deoxynucleotide transferase-mediated terminal uridine deoxynucleotidyl transferase nick end-labeling (TUNEL) method. To investigate the neuroprotective mechanism of maltol, the expression and phosphorylation of nuclear factor-kappa B (NF-κB), extracellular signal-regulated kinase (ERK), c-Jun N-terminal kinase (JNK), and p38 were evaluated by Western immunoblot analysis.
Results
R28 cells exposed to H2O2 were found to have decreased viability in a dose- and time-dependent manner. However, H2O2-induced cytotoxicity was decreased with the addition of maltol. When R28 cells were exposed to 1.0 mM H2O2 for 24 hours, the cytotoxicity was 60.69 ± 5.71%. However, the cytotoxicity was reduced in the presence of 1.0 mM maltol. This H2O2-induced cytotoxicity caused apoptosis of R28 cells, characterized by DNA fragmentation. Apoptosis of oxidatively-stressed R28 cells with 1.0 mM H2O2 was decreased with 1.0 mM maltol, as determined by the TUNEL method. Western blot analysis showed that treatment with maltol reduced phosphorylation of NF-κB, ERK, and JNK, but not p38. The neuroprotective effects of maltol seemed to be related to attenuated expression of NF-κB, ERK, and JNK.
Conclusions
Maltol not only increased cell viability but also attenuated DNA fragmentation. The results obtained here show that maltol has neuroprotective effects against hypoxia-induced neuroretinal cell damage in R28 cells, and its effects may act through the NF-κB and mitogen-activated protein kinase signaling pathways.
doi:10.3341/kjo.2015.29.1.58
PMCID: PMC4309870  PMID: 25646062
Maltol; Neuroprotection; Oxidative stress; Rat retinal neuronal cell
2.  Instability of 24-hour intraocular pressure fluctuation in healthy young subjects: a prospective, cross-sectional study 
BMC Ophthalmology  2014;14(1):127.
Background
Elevated intraocular pressure (IOP) is a major risk factor for the development and/or progression of glaucoma, and a large diurnal IOP fluctuation has been identified as an independent risk factor of glaucoma progression. However, most previous studies have not considered the repeatability of 24-hour IOP measurements. The aim of this study was to evaluate the instability of 24-hour IOP fluctuations in healthy young subjects.
Methods
Ten healthy young volunteers participated in this prospective, cross-sectional study. Each subject underwent 24-hour IOP and systolic/diastolic blood pressure (SBP/DBP) assessments both in sitting and supine positions every 3 hours, once a week for 5 consecutive weeks. Mean ocular perfusion pressure (MOPP) was then calculated for both positions. The intraclass correlation coefficients (ICCs) of maximum, minimum, and fluctuation parameters were computed for IOP, SBP/DBP, and MOPP. Fluctuation was defined as the difference between maximum and minimum values during a day.
Results
Among the serial measurements taken over a 24-hour rhythm, the maximum/minimum values of IOP, as well as BP, showed excellent agreement: regardless of position, all ICC values were over 0.800. Most of the BP fluctuation values also showed excellent agreement. IOP fluctuation, however, did not show excellent agreement; the ICC of sitting IOP fluctuation was just 0.212. MOPP fluctuation also showed poor agreement, especially in the sitting position (ICC, 0.003).
Conclusion
On a day to day basis, 24-hour IOP fluctuations were not highly reproducible in healthy young volunteers. Our results imply that a single 24-hour IOP assessment may not be a sufficient or suitable way to characterize circadian IOP fluctuations for individual subjects.
doi:10.1186/1471-2415-14-127
PMCID: PMC4232688  PMID: 25370361
Blood pressure; Fluctuation; Glaucoma; Intraocular pressure
3.  Systemic Hypertension as a Risk Factor for Open-Angle Glaucoma: A Meta-Analysis of Population-Based Studies 
PLoS ONE  2014;9(9):e108226.
Background/Aims
Systemic hypertension is thought to increase the risk for developing open-angle glaucoma (OAG) through several mechanisms. However, previous epidemiological studies have shown conflicting results regarding this potential association. We systematically evaluated this issue by conducting a meta-analysis of population-based studies.
Methods
A comprehensive search for articles published before 31 March 2014 was performed using PubMed, Embase, and reference lists. The pooled odds ratio (OR) was calculated using the fixed- and random-effects models, and meta-regression was performed according to age. Subgroup analyses were also conducted, and publication bias was assessed using a funnel plot and Egger’s regression test.
Results
This meta-analysis included 16 studies involving 60,084 individuals, with substantial homogeneity among the studies. The pooled OR for OAG was 1.22 (95% confidence interval, CI: 1.09–1.36) using the fixed-effects model and 1.22 (95% CI: 1.08–1.37) using the random-effects model in all included studies. For subgroup analyses, the pooled OR for high-tension glaucoma (HTG) was higher than that for normal-tension glaucoma (NTG) (OR = 1.92 and 0.94, respectively). No significant difference was detected between Asian and Western populations, and no publication bias was detected in either analysis.
Conclusions
Systemic hypertension increases the risk for developing OAG, especially in those with HTG.
doi:10.1371/journal.pone.0108226
PMCID: PMC4177901  PMID: 25254373
4.  Retroviral expression of human arginine decarboxylase reduces oxidative stress injury in mouse cortical astrocytes 
BMC Neuroscience  2014;15(1):99.
Background
In physiologic and pathologic conditions of the central nervous system (CNS), astrocytes are a double-edged sword. They not only support neuronal homeostasis but also contribute to increases in neuronal demise. A large body of experimental evidence has shown that impaired astrocytes play crucial roles in the pathologic process of cerebral ischemia; therefore, astrocytes may represent a breakthrough target for neuroprotective therapeutic strategies. Agmatine, an endogenous polyamine catalyzed from L-arginine by arginine decarboxylase (ADC), is a neuromodulator and it protects neurons/glia against various injuries.
Results
In this investigation, agmatine-producing mouse cortical astrocytes were developed through transduction of the human ADC gene. Cells were exposed to oxygen-glucose deprivation (OGD) and restored to a normoxic glucose-supplied condition. Intracellular levels of agmatine were measured by high performance liquid chromatography. Cell viability was evaluated by Hoechest/propidium iodide nuclear staining and lactate dehydrogenase assay. Expression of inducible nitric oxide synthase (iNOS) and matrix metalloproteinase s (MMPs) were assessed by a reverse transcription polymerase chain reaction, Western immunoblots, and immunofluorescence. We confirmed that ADC gene-expressed astrocytes produce a great amount of agmatine. These cells were highly resistant to not only OGD but also restoration, which mimicked ischemia-reperfusion injury in vivo. The neuroprotective effects of ADC seemed to be related to its ability to attenuate expression of iNOS and MMPs.
Conclusion
Our findings imply that astrocytes can be reinforced against oxidative stress by endogenous agmatine production through ADC gene transduction. The results of this study provide new insights that may lead to novel therapeutic approaches to reduce cerebral ischemic injuries.
Electronic supplementary material
The online version of this article (doi:10.1186/1471-2202-15-99) contains supplementary material, which is available to authorized users.
doi:10.1186/1471-2202-15-99
PMCID: PMC4150973  PMID: 25156824
Agmatine; Arginine decarboxylase; Astrocyte; Neuroprotection; Oxidative stress
5.  Effect of Korean Red Ginseng supplementation on dry eye syndrome in glaucoma patients – A randomized, double-blind, placebo-controlled study 
Journal of Ginseng Research  2014;39(1):7-13.
Background
Many patients with glaucoma have difficulty using antiglaucoma eye drops because of dry eye symptom. In this prospective, randomized, double-blind, placebo-controlled study, we evaluated the effect of Korean Red Ginseng on dry eye syndrome in patients with glaucoma treated with antiglaucoma eye drops.
Methods
Forty-nine participants were allocated to the Korean Red Ginseng (3 g/day; n = 24) or placebo (n = 25) groups for 8 weeks. Tear film stability, fluorescein corneal staining, conjunctival hyperemia, tear production, grade of meibomian gland dysfunction, and dry eye questionnaire (Ocular Surface Disease Index) were evaluated at baseline and on completion of the treatment.
Results
Almost all patients displayed dry eye symptoms and signs at baseline. After the 8-week intervention, Korean Red Ginseng supplementation significantly improved the tear film stability and total Ocular Surface Disease Index score, as compared to placebo (p < 0.01).
Conclusion
Korean Red Ginseng supplementation may provide an additional treatment option for dry eye and patients with glaucoma using antiglaucoma eye drops.
doi:10.1016/j.jgr.2014.07.002
PMCID: PMC4268561  PMID: 25535471
dry eye syndrome; glaucoma; Korean Red Ginseng; Panax ginseng
6.  Adjusted color probability codes for peripapillary retinal nerve fiber layer thickness in healthy Koreans 
BMC Ophthalmology  2014;14:38.
Background
Though a newly developed spectral domain optical coherence tomography (OCT) is at the center of interests for many ophthalmologic researchers and clinicians, its own characteristics are not fully evaluated yet. The main purpose of this study was to establish the adjusted color probability codes for peripapillary retinal nerve fiber layer (RNFL) thickness in healthy Koreans and to compare them with original color codes provided by spectral domain OCT.
Methods
Two hundred ninety-five healthy Korean eyes were enrolled and their peripapillary RNFL thickness was measured by Cirrus OCT. For each decade of age, the normal thickness reference was determined on the basis of z-scores and the adjusted color probability codes were established. Then the agreements between adjusted and original color codes were calculated using weighted Kappa (Kw) coefficient.
Results
On the basis of Kw coefficient, the overall agreement between the adjusted and original probability color codes was not excellent (Kw range of 0.500 to 0.806). If the adjusted probability codes were assumed as a standard of comparison, the original color codes showed the false-negative in 11% of eyes and the false-positive in 0.3% of eyes for average RNFL thickness.
Conclusions
Adjusted color probability codes judged by the Korean normative data showed a discrepancy with original codes. It implies that normal reference and adjusted probability codes for each ethnicity might be needed to determine whether a certain RNFL thickness is within normal range or not.
doi:10.1186/1471-2415-14-38
PMCID: PMC3995502  PMID: 24678925
Glaucoma; Optical coherence tomography; Probability code; Retinal nerve fiber layer
7.  Neuroprotective and neurite outgrowth effects of maltol on retinal ganglion cells under oxidative stress 
Molecular Vision  2014;20:1456-1462.
Purpose
To evaluate the neuroprotective and neurite outgrowth effects of maltol, a natural aroma compound, on retinal ganglion cells (RGCs) under oxidative stress in vitro.
Methods
Mouse primary RGCs were isolated using immunopanning–magnetic separation and exposed to H2O2 in the presence of maltol. The cell viability and apoptosis were determined by using adenosine 5′-triphosphate (ATP) assay and terminal deoxynucleotidyl transferase (TdT)-mediated deoxyuridine triphosphate (dUTP) nick end labeling (TUNEL), respectively. Neurite outgrowth was assessed by immunofluorescence for α-tubulin. The activation of nuclear factor-κB (NF-κB) was also evaluated using immunofluorescence.
Results
When the RGCs were exposed to 20 μM of H2O2 for 16 h, their viability dropped to 40.3±3.4%. However, the maltol treatment restored the cells in a dose-dependent manner. The viability recovered to 73.9±5.1% with 10 μM of maltol and even reached 175.1±11.3% with 2 mM of maltol, as measured by ATP assay. This oxidative stress significantly increased the number of TUNEL-positive RGCs, but the maltol drastically reduced the proportion of those apoptotic cells. The oxidative stress hampered the neurite outgrowth of the RGCs, whereas maltol restored their ability to sprout neurites. Regarding NF-κB, the active form of phosphorylated NF-κB (pNF-κB) increased the oxidative stress level but the maltol treatment again reduced it to an unstressful level.
Conclusions
Our data revealed that maltol attenuated the oxidative stress–induced injury in the primary mouse RGCs. Its neuroprotective and neurite outgrowth effects seemed to be related to NF-κB signaling. Maltol has potential as a new neuroprotective therapeutic agent for oxidative stress–related ocular diseases, including glaucoma.
PMCID: PMC4203576  PMID: 25352751
8.  Serodiagnosis of Echinococcosis by ELISA Using Cystic Fluid from Uzbekistan Sheep 
According to increase of travel, the cases of imported echinococcosis have been increasing in Korea. The present study was undertaken to develop a serodiagnostic system for echinococcosis in Korea. For diagnosis of echinococcosis, the fluid of Echinococcus granulosus hydatid cysts was collected from naturally infected sheep in Uzbekistan. Also serum samples of infected patients who were surgically confirmed were collected in a hospital in Tashkent, Uzbekistan. According to the absorbance of 59 echinococcosis positive and 39 negative control serum samples, the cut-off value was determined as 0.27. The sensitivity and specificity of ELISA with hydatid fluid antigen were 91.5% and 96%, respectively. The antigen cross-reacted with the serum of some cysticercosis or clonorchiasis patients. However, immunoblot analysis on the cystic fluid recognized antigenic proteins of 7-, 16-, and 24-kDa bands in their dominant protein quantity and strong blotting reactivity. In conclusion, the present ELISA system using hydatid cyst fluid antigen from Uzbekistan sheep is sensitive and specific for diagnosis of echinococcosis cases.
doi:10.3347/kjp.2013.51.3.313
PMCID: PMC3712105  PMID: 23864742
Echinococcus granulosus; echinococcosis; serodiagnosis; ELISA; cystic fluid antigen
9.  Infection Status of Hydatid Cysts in Humans and Sheep in Uzbekistan 
Uzbekistan is endemic of cystic echinococcosis (CE). In order to estimate endemicity of CE, we collected data from emergency surgery due to CE in 2002-2010 and also investigated the prevalence of hydatid cysts in the liver and lungs of sheep at an abattoir in Uzbekistan from July 2009 to June 2010. In 14 emergency hospitals, 8,014 patients received surgical removal or drainage of CE during 2002-2010, and 2,966 patients were found in 2010. A total of 22,959 sheep were grossly examined of their liver and lungs, and 479 (2.1%) and 340 (1.5%) of them were positive for the cyst in the liver and lungs, respectively. Echinococcus granulosus is actively transmitted both to humans and sheep, and CE is a zoonotic disease of public health priority in Uzbekistan.
doi:10.3347/kjp.2013.51.3.383
PMCID: PMC3712117  PMID: 23864754
Echinococcus granulosus; emergency surgery; sheep; Uzbekistan
10.  Long-term Results of Deep Sclerectomy with Small Collagen Implant in Korean 
Purpose
To describe the long-term results of deep sclerectomy with collagen implant (DSCI) with or without adjuvant mitomycin C in Korean patients with primary or secondary open-angle glaucoma (OAG).
Methods
This retrospective review was comprised of 65 Korean patients who received DSCI with or without adjuvant mitomycin C due to primary or secondary OAG. Patients were followed for 72 months after surgery. Complete success was defined as intraocular pressure (IOP) <21 mmHg without medication and qualified success was defined as IOP <21 mmHg with or without medication.
Results
Mean postoperative follow-up period was 53.0 ± 16.2 months. Mean IOP was 30.5 ± 11.7 mmHg preoperatively, 8.4 ± 4.3 mmHg at postoperative day one and 13.4 ± 3.8 mmHg 60 months after surgery. The mean number of glaucoma medications was decreased from 3.6 ± 1.1 to 1.6 ± 1.3 at 60 months after the operation. Complete and qualified success rates were 36.7% and 79.6% at postoperative 60 months, respectively (Kaplan-Meier survival curve). No shallow or flat anterior chamber, endophthalmitis, or surgery-induced significant cataract was observed.
Conclusions
The results of DSCI in Korean patients presented here seem reasonably excellent with qualified success rates of over 70% at six years with negligible complications.
doi:10.3341/kjo.2013.27.1.34
PMCID: PMC3550309  PMID: 23372377
Deep sclerectomy; Koreans; Open-angle glaucoma; Small collagen implant
11.  Role of Heat Shock Protein 47 in Transdifferentiation of Human Tenon's Fibroblasts to Myofibroblasts 
BMC Ophthalmology  2012;12:49.
Background
Heat shock protein 47 (Hsp47) is a well-known molecular chaperone in collagen synthesis and maturation. The aim of this study is to investigate its putative role in the transdifferentiation of Tenon’s fibroblasts to myofibroblasts.
Methods
Primary cultured human Tenon’s fibroblasts were exposed to transforming growth factor-β1 (TGF-β1) for up to 48 hours. The mRNA levels of Hsp47 and α smooth muscle actin (αSMA) were determined by quantitative real time RT-PCR. After delivery of small interfering RNA (siRNA) molecules targeting Hsp47 into the cells, the expression of Hsp47 and αSMA proteins was determined by western immunoblotting.
Results
TGF-β1 increased the mRNA expressions of both Hsp47 and αSMA in human Tenon’s fibroblasts, as determined by quantitative real time RT-PCR. However, it induced the protein expression of only αSMA but not Hsp47, as determined by western immunoblots. When siRNAs specific for Hsp47 were introduced into those cells, the TGF-β1-induced expression of αSMA was significantly attenuated on western immunoblots; after 48 hours of exposure to TGF-β1, the relative densities of immunobands were 11.58 for the TGF-β1 only group and 2.75 for the siRNA treatment group, compared with the no treatment control group (p < 0.001).
Conclusions
Our data suggest that Hsp47 may be related to the TGF-β1-induced transdifferentiation of human Tenon’s fibroblasts to myofibroblasts.
doi:10.1186/1471-2415-12-49
PMCID: PMC3490793  PMID: 22967132
Fibroblast; Fibrosis; Heat shock protein; Myofibroblast; Transforming growth factor-β
12.  The Role of Focal Adhesion Kinase in the TGF-β-Induced Myofibroblast Transdifferentiation of Human Tenon's Fibroblasts 
Purpose
To investigate the role of focal adhesion kinase (FAK) in transforming growth factor (TGF)-β-induced myofibroblast transdifferentiation of human Tenon's fibroblasts.
Methods
Primary cultured human Tenon's fibroblasts were exposed to TGF-β1 for up to 48 hours. The mRNA levels of FAK, α smooth muscle actin (αSMA), and β-actin were determined by quantitative real time reverse transcription polymerase chain reaction. The protein levels of collagen type I, FAK, phospho-FAK, αSMA, and β-actin were determined by Western immunoblots. After the small interfering RNA targeting FAK (siRNAFAK) molecules were delivered into the cells, the expressions of αSMA proteins were determined by Western immunoblots.
Results
In human Tenon's fibroblasts, TGF-β1 significantly increased the mRNA and protein expressions of αSMA. However, when the action of FAK was inhibited using siRNAFAK, the TGF-β1-induced expression of αSMA was attenuated.
Conclusions
Our data suggest that FAK may be associated with the TGF-β1-induced transdifferentiation of human Tenon's fibroblasts to myofibroblasts, which is the essential step of subconjunctival fibrosis.
doi:10.3341/kjo.2012.26.1.45
PMCID: PMC3268168  PMID: 22323885
Fibroblast; Focal adhesion protein-tyrosine kinases; Myofibroblast; Transforming growth factors
13.  Recession-Resection Surgery Augmented with Botulinum Toxin A Chemodenervation for Paralytic Horizontal Strabismus 
In this case series study, we assessed the effects of recession-resection surgery augmented with botulinum toxin A chemodenervation for patients with chronic paralytic horizontal strabismus. In addition, we compared these effects with those of full tendon transposition (FTT) augmented with posterior intermuscular suture (PIMS). Ten patients who underwent strabismus surgery due to paralytic horizontal strabismus were retrospectively reviewed. They received a recession-resection surgery augmented with botulinum toxin A chemodenervation (type I surgery) or a FTT augmented with PIMS (type II surgery). The preoperative angle of deviation (AOD) and postoperative improvement in AOD were compared according to the type of procedure. The preoperative AOD was 60.00 ± 28.50 prism diopters (PD) for type I surgery and 68.00 ± 27.06 PD for type II (p = 0.421). Improvement in AOD was 53.20 ± 25.01 PD for type I surgery and 44.20 ± 18.74 PD for type II (p = 0.548). Recession-resection surgery augmented with botulinum toxin A chemodenervation is a concise and effective procedure for treating paralytic horizontal strabismus.
doi:10.3341/kjo.2012.26.1.69
PMCID: PMC3268175  PMID: 22323891
Botulinum toxins type A; Paralytic strabismus; Recession-resection surgery
14.  Attenuated Age-Related Thinning of Peripapillary Retinal Nerve Fiber Layer in Long Eyes 
Purpose
To assess the impact of axial length on the age-related peripapillary retinal nerve fiber layer (RNFL) thinning.
Methods
This cross-sectional observational comparative case series included 172 eyes from 172 healthy Korean subjects. Peripapillary RNFL thickness was measured using an Optic Disc Cube 200 × 200 scan of spectral domain Cirrus HD OCT and the axial length was measured using IOL Master Advanced Technology. In age groups based on decade, the normal ranges of peripapillary RNFL thickness for average, quadrant, and clock-hour sectors were determined with 95% confidence intervals. After dividing the eyes into two groups according to axial length (cut-off, 24.50 mm), the degrees of age-related RNFL thinning were compared.
Results
Among the eyes included in the study, 53 (30.81%) were considered to be long eyes (axial length, 25.04 ± 0.48 µm) and 119 (69.19%) were short-to-normal length eyes (axial length, 23.57 ± 0.60 µm). The decrease in average RNFL thickness with age was less in long eyes (negative slope, -0.12 µm/yr) than in short-to-normal length eyes (negative slope, -0.32 µm/yr) (p < 0.001).
Conclusions
Age-related thinning of peripapillary RNFL thickness is attenuated in long eyes compared to short-to-normal length eyes.
doi:10.3341/kjo.2011.25.4.248
PMCID: PMC3149135  PMID: 21860571
Axial length; Glaucoma; Optical coherence tomography; Retinal ganglion cell
15.  Transient Increase of Higher-Order Aberrations after Lateral Rectus Recession in Children 
Yonsei Medical Journal  2011;52(3):527-529.
The changes of higher-order aberrations (HOAs) after bilateral lateral rectus muscle recession were evaluated. Forty eyes of 20 children were enrolled and their wavefront information was assessed until postoperative 3 months. Even though the root mean square (RMS) of total aberration was not changed, the RMS of HOA was transiently increased at postoperative 1 week and returned to baseline level after 1 month. Among individual Zernike coefficient, secondary astigmatism, quadrafoil, secondary coma, secondary trefoil, and pentafoil showed similar tendency with the RMS of HOA. However, coma, trefoil, and spherical aberration were not changed. Regarding recession amount, it did not correlate with any Zernike coefficient. In summary, our data imply that the HOAs are transiently increased after lateral rectus recession surgery. These results are in collusion with previous reports that strabismus surgery induced transient corneal astigmatism.
doi:10.3349/ymj.2011.52.3.527
PMCID: PMC3101054  PMID: 21488198
Astigmatism; higher-order aberrations; lateral rectus muscle recession
16.  Inter-Device Agreement of Retinal Nerve Fiber Layer Thickness Measurements Using Spectral Domain Cirrus HD OCT 
Purpose
To assess the inter-device agreement of peripapillary retinal nerve fiber layer (RNFL) thickness measurements by 2 spectral domain Cirrus HD optical coherence tomography (OCT) devices in healthy Korean subjects.
Methods
Eleven eyes of 11 healthy volunteers were enrolled in the present study. Each eye was scanned with the Optic Disc Cube 200 × 200 scan of 2 Cirrus HD OCT devices for peripapillary RNFL thickness calculation. The inter-device agreements of the 2 Cirrus HD OCTs for average, quadrant, and clock-hour RNFL thickness values were determined with Wilcoxon signed rank test, Friedman test, Cronbach's alpha (α), intraclass correlation coefficient (ICC), coefficient of variation (COV), and Bland-Altman plot.
Results
The mean age of the participants was 25.82 ± 3.28 years and all had a 0.00 logarithm of the minimum angle of resolution of best-corrected visual acuity. The signal strengths of scans from the 2 Cirrus HD OCT were not significantly different (p = 0.317). The inter-device agreement of average RNFL thickness was excellent (α, 0.940; ICC, 0.945; COV, 2.45 ± 1.52%). However, the agreement of nasal quadrant RNFL thickness was not very good (α, 0.715; ICC, 0.716; COV, 5.72 ± 4.64%). Additionally, on the Bland-Atman plot, the extent of agreement of the 2 Cirrus HD OCTs for RNFL thickness was variable according to scanned sectors.
Conclusions
The inter-device agreement of 2 spectral domain Cirrus HD OCT devices for peripapillary RNFL thickness measurements was generally excellent but variable according to the scanned area. Thus, physicians should consider this fact before judging a change of RNFL thicknesses if they were measured by different OCT devices.
doi:10.3341/kjo.2011.25.2.105
PMCID: PMC3060386  PMID: 21461222
Inter-device agreement; Optical coherence tomography; Retinal nerve fiber layer thickness
17.  Prevalence and Characteristics of Glaucoma among Korean Adults 
Purpose
The purpose of this study was to investigate the prevalence and characteristics of glaucoma in the population of the rural Korean town, Sangju.
Methods
Residents of Sangju aged greater than 50 years old were included in this study. Participants completed an interview examining their medical and ophthalmic history Information was collected on the participants' uncorrected and best corrected vision scores, slit lamp examination results, angle width measurements using the Van Herick technique, gonioscopy if the angle width was less than 1 / 4 angle, intraocular pressure (IOP) assessed with the Goldmann applanation tonometry, optic disc examination results, and a visual field test results using frequency-doubling perimetry in cases in which glaucoma was suspected. Glaucoma was diagnosed according to the criteria described by the International Society for Geographic and Epidemiological Ophthalmology.
Results
1,118 residents aged greater than 50 years were examined initially from a population of 2,984 people. Of these, 671 subjects (60%) participated in this study. The prevalence of glaucoma was determined to be 3.4% (95% confidence interval [CI], 2.1-4.8). Open-angle glaucoma with low IOP was determined to be the most common form with a prevalence rate as high as 2.5% (95% CI, 1.8-3.7). Additionally, primary angle closure glaucoma was determined to have a prevalence rate of 0.3% (95% CI, 0.1-0.9). Open-angle glaucoma with low IOP accounted for 94.4% of the open-angle glaucoma cases.
Conclusions
The prevalence of glaucoma among the population of rural Sangju was 3.4%, and open-angle glaucoma with low IOP was the most common form accounting for 94.4% of the total number of cases.
doi:10.3341/kjo.2011.25.2.110
PMCID: PMC3060387  PMID: 21461223
Epidemiology; Glaucoma; Open angle glaucoma; Prevalence
18.  Phacoemulsification Alone versus Phacoemulsification Combined with Trabeculectomy for Primary Angle-Closure Glaucoma 
Yonsei Medical Journal  2010;51(5):781-783.
Surgical outcomes of phacoemulsification only and phacoemulsification combined with trabeculectomy were compared in patients with primary angle-closure glaucoma (PACG). Clinical records of 41 consecutive patients were retrospectively reviewed, and there was no difference in best-corrected visual acuity and intraocular pressure preoperatively and at the final follow-up in both study groups. Regarding the number of anti-glaucoma medications, it was higher in the phacoemulsification combined with trabeculectomy group preoperatively than the phacoemulsification only group (p = 0.045), but both groups were taking similar quantities of medication at the final follow-up (p = 0.6). In addition, postoperative hypotony (two cases) occurred only after phacoemulsification combined with trabeculectomy, but not after phacoemulsification only. In one case after phacoemulsification only, a second operation was needed. There were no additional postoperative complications. In conclusion, both phacoemulsification only and phacoemulsification combined with trabeculectomy showed good surgical outcomes in PACG patients. Both procedures might be equally effective in treating patients with PACG.
doi:10.3349/ymj.2010.51.5.781
PMCID: PMC2908889  PMID: 20635456
Phacoemulsification; phacoemulsification combined with trabeculectomy; primary angle-closure glaucoma
19.  Unilateral Recession-Resection Surgery with Inferior Displacement Combined with Augmented Anterior Transposition of Inferior Oblique Muscle 
We report the effects of unilateral recession-resection surgery of the horizontal recti muscles with inferior displacement and augmented anterior transposition of the inferior oblique muscle with a posterior intermuscular suture in a patient with large exotropia and considerable hypertropia.
doi:10.3341/kjo.2010.24.3.189
PMCID: PMC2882087  PMID: 20532150
Strabismus
20.  Drug Attitude and Adherence to Anti-Glaucoma Medication 
Yonsei Medical Journal  2010;51(2):261-269.
Purpose
The purpose of this study is to assess patient attitudes towards anti-glaucoma medication and their association with adherence, visual quality of life, and personality traits.
Materials and Methods
One hundred and forty-seven glaucoma patients were enrolled this study. The participants were divided into 'pharmacophobic' and 'pharmacophilic' groups according to their scores on the Modified Glaucoma Drug Attitude Inventory (MG-DAI). To establish a correlation with patient drug attitude, each group had their subjective drug adherence, visual quality of life, and personality traits examined. For personality traits, the Myers-Briggs Type Indicator (MBTI) was used to sub-classify each group.
Results
Among the patients analyzed, 91 (72.80%) patients showed a 'pharmacophobic' attitude and 34 (27.20%) patients showed a 'pharmacophilic' attitude. The pharmacophobic group tended to have worse adherence than the pharmacophilic group. Personality dichotomies from the MBTI also showed different patterns for each group.
Conclusion
In glaucoma patients, pharmacological adherence was influenced by their attitude towards drugs; an association might exist between drug attitude and underlying personality traits.
doi:10.3349/ymj.2010.51.2.261
PMCID: PMC2827921  PMID: 20191020
Adherence; drug attitude; glaucoma; personality
21.  Detection of Occludable Angles with the Pentacam and the Anterior Segment Optical Coherence Tomography 
Yonsei Medical Journal  2009;50(4):525-528.
Purpose
To assess efficacy of the Pentacam (PTC) and the anterior segment optical coherence tomography (AOCT) for detection of occludable angles.
Materials and Methods
Fourty-one eyes with gonioscopically diagnosed occludable angles and 32 normal open-angle eyes were included. Anterior chamber angle (ACA) and anterior chamber depth (ACD) were measured with PTC and AOCT. Receiver operating characteristic (ROC) curve was constructed for each parameter and the area under the ROC curve (AUC) was calculated.
Results
Values of ACA and ACD measured by PTC and AOCT were similar not only in normal open angle eyes but also in occludable angle eyes. For detection of occludable angle, the AUCs of PTC with ACA and ACD were 0.935 and 0.969, respectively. The AUCs of AOCT with ACA and ACD were 0.904 and 0.947, respectively.
Conclusion
Both PTC and AOCT allow accurate discrimination between open and occludable angle eyes, so that they may aid to screening the occludable angles.
doi:10.3349/ymj.2009.50.4.525
PMCID: PMC2730615  PMID: 19718401
Pentacam; anterior segment optical coherence tomography; occludable angle; anterior chamber angle; anterior chamber depth
22.  Inaccuracy of Intraocular Lens Power Prediction for Cataract Surgery in Angle-Closure Glaucoma 
Yonsei Medical Journal  2009;50(2):206-210.
Purpose
To assess the accuracy of intraocular lens (IOL) power predictions for cataract surgery in eyes with primary angle-closure glaucoma (ACG). Because of shifting of the capsular bag apparatus and shortening of the axial length, preoperative calculation of IOL power may be inaccurate for eyes with ACG.
Materials and Methods
This retrospective comparative case series comprised of 42 eyes from 42 patients with primary ACG and 45 eyes from 45 subjects with normal open-angles undergoing uneventful cataract surgery. Anterior segment biometry including anterior chamber depth, lens thickness, and axial length were compared. Using the SRK-II formula, the powers of the implanted IOL and the actual postoperative spherical equivalent (SE) refractive errors were compared between the two groups. Also, the absolute values of differences between predicted and residual SE refractive errors were also analyzed for each group.
Results
In ACG patients, anterior chamber depth and axial length were shorter and the lens was thicker than normal controls (all p < 0.001). Even though residual SE refractive error was not significantly different (p = 0.290), the absolute value of the difference between predicted and residual SE refractive error was 0.64 ± 0.50 diopters in AGC patients and 0.39 ± 0.36 diopters in control subjects (p = 0.012). The number of eyes that resulted in inaccurate IOL power predictions of more than 0.5 diopters were 21 (50.00%) in the ACG group, but only 12 (26.67%) in the control group (p = 0.043).
Conclusion
IOL power predictions for cataract surgery in ACG patients can be inaccurate, and it may be associated with their unique anterior segment anatomy.
doi:10.3349/ymj.2009.50.2.206
PMCID: PMC2678694  PMID: 19430552
Angle-closure; cataract; glaucoma; intraocular lens
23.  TGF-β-induced interleukin-6 participates in transdifferentiation of human Tenon’s fibroblasts to myofibroblasts 
Molecular Vision  2009;15:2123-2128.
Purpose
To gain a better understanding of the roles of interleukins (ILs) in subconjunctival fibrosis, we investigated their expression in transforming growth factor-β1 (TGF-β1)-stimulated Tenon’s fibroblasts and examined their association with the transdifferentiation of fibroblasts to myofibroblasts.
Methods
After primary culture, fibroblasts derived from human Tenon’s capsule were exposed to TGF-β1. The expression of α-smooth muscle actin (α-SMA) protein was assessed by western immunoblots and immunofluorescence. The mRNA levels of various ILs were also evaluated by multiplex reverse transcription (RT)-PCR. Using the small interfering RNAs (siRNAs) specific for IL-6 and IL-11 and the promoter deletion assay, the contributions of IL-6 and IL-11 to TGF-β1-induced induction of α-SMA were determined.
Results
In human Tenon’s fibroblasts, TGF-β1 stimulated the expression of α-SMA protein determined by western blot analysis and also increased the mRNA levels of IL-6 and IL-11 determined by multiplex RT-PCR. On the western immunoblots and immunofluorescence, the increased expression of α-SMA was attenuated only by the siRNAs specific for IL-6 but not by the siRNAs specific for IL-11. When the activator protein-1 binding sites of the IL-6 promoter region were deleted, the stimulation effects of TGF-β1 decreased.
Conclusions
Our data show that autocrine IL-6 may participate in the TGF-β1-induced transdifferentiation of human Tenon’s fibroblasts to myofibroblasts, which is known to be an essential step for subconjunctival fibrosis.
PMCID: PMC2765236  PMID: 19862334
25.  Pattern Visual Evoked Potential as a Predictor of Occlusion Therapy for Amblyopia 
Purpose
This study was conducted to investigate the role of the pattern visual evoked potential (pVEP) as a predictor of occlusion therapy for patients with strabismic, anisometropic, and isometropic amblyopia. The secondary aim was to compare the characteristics of pVEP between strabismic and anisometropic amblyopia.
Methods
This retrospective comparative case series included 120 patients who had received occlusion therapy or a glasses prescription for correction of strabismic, anisometropic, and isometropic amblyopia (20 patients had strabismic amblyopia, 41 patients had anisometropic amblyopia, and 59 patients had isometropic amblyopia). For each patient, the value of the P100 latency on pVEP at the time of the initial diagnosis of amblyopia was collected. Subsequently, the P100 latency was compared according to types of amblyopia. Fifty of 120 patients (7 patients with strabismic amblyopia, 21 patients with anisometropic amblyopia, and 22 patients with isometropic amblyopia) who were followed-up for longer than 6 months were divided into two groups based on the value of their P100 latency (Group 1, P100 latency 120 msec or less; Group 2, P100 latency longer than 120 msec.) The amount of visual improvement after occlusion therapy or glasses was compared between two study groups.
Results
The mean P100 latency was 119.7±25.2 msec in eyes with strabismic amblyopia and 111.9±17.8 msec in eyes with non-strabismic (anisometropic or isometropic) amblyopia (p=0.213). In Group 1, the mean visual improvement after occlusion therapy or glasses was 3.69±2.14 lines on Dr. Hahn's standard test chart; in Group 2, the mean improvement was 2.27±2.21 lines (p=0.023).
Conclusions
The P100 latency on pVEP at the time of initial diagnosis was significantly related to the visual improvement after occlusion therapy or glasses in patients with strabismic, anisometropic, and isometropic amblyopia. Therefore, it was presumed that patients with a delayed P100 latency might have less visual improvement after occlusion therapy or glasses. In addition, there was no apparent difference in P100 latency between patients with strabismic and non-strabismic (anisometropic or isometropic) amblyopia.
doi:10.3341/kjo.2008.22.4.251
PMCID: PMC2629911  PMID: 19096243
Amblyopia; P100 latency; Visual evoked potential

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