Gong Je Seong

Comparison of laser epithelial keratomileusis and photorefractive keratectomy for low to moderate myopia

Purpose: To compare the effectiveness, safety, and stability of laser epithelial keratomileusis (LASEK), a modified photorefractive keratectomy (PRK) technique, with those of conventional PRK for low to moderate myopia. Setting: Department of Ophthalmology, Yonsei University School of Medicine, Seoul, Korea. Methods: In this prospective study, 27 patients with a manifest refraction of –3.00 to –6.50 diopters were treated and followed for 3 months. In each case, PRK was performed in 1 eye and LASEK in the other eye. The first eye treated and the surgical method used in the first eye were randomized. Postoperative pain, epithelial healing time, uncorrected visual acuity (UCVA), manifest refraction, corneal haze, and surgical preference were examined in PRK‐ and LASEK‐treated eyes. Results: During the 3 month follow‐up, there were no significant between‐eye differences in epithelial healing time, UCVA, or refractive error. However, LASEK‐treated eyes had lower postoperative pain scores (P = .047) and corneal haze scores (1 month; P = .02) than PRK‐treated eyes. Seventeen patients (63%) preferred the LASEK procedure. Conclusions: Laser epithelial keratomileusis safely and effectively treated eyes with low to moderate myopia. It reduced the incidence of significant postoperative pain and corneal haze and may prevent the flap‐ and interface‐related problems of laser in situ keratomileusis.

Prevalence of Primary Open-Angle Glaucoma in Central South Korea: The Namil Study

PURPOSE To assess the prevalence of primary open-angle glaucoma (POAG) in the Namil-myon area in central South Korea. DESIGN A cross-sectional, epidemiologic study in a defined population. PARTICIPANTS Residents aged ≥ 40 years in Namil-myon, a rural agricultural area in central South Korea. METHODS Each subject underwent a screening that consisted of an interview and ophthalmic examinations, including visual acuity measurement, autorefraction, anterior segment evaluation by optical biometry, slit-lamp examination, Goldmann applanation tonometry, binocular optic disc evaluation, fundus photography, pachymetry, gonioscopy, and screening visual field test using frequency doubling technology. Subjects with suspected glaucoma were referred for definitive examinations. Standard automated field tests and retinal nerve fiber layer analysis using optical coherence tomography (Stratus OCT) or scanning laser polarimetry (GDx VCC) were performed. A diagnosis of glaucoma was made based on the optic disc shape, retinal nerve fiber layer appearance, perimetric results, and other ocular findings. MAIN OUTCOME MEASURES Prevalence of POAG, mean intraocular pressure (IOP), and mean central corneal thickness (CCT). RESULTS Of 1928 eligible residents in the area, 1532 (79.5%) participated in this study. The estimated prevalence of POAG in the population aged ≥ 40 years was 3.5% (95% confidence interval [CI], 2.7%-4.3%). The prevalence of POAG with an IOP of ≤ 21 mmHg was 2.7% (95% CI, 2.1%-3.3%), and the prevalence of POAG with an IOP of ≥ 22 mmHg was 0.8% (95% CI, 0.4%-1.2%). The mean IOP for POAG eyes (16.3 ± 4.6 mmHg) was significantly higher than nonglaucomatous eyes (13.3 ± 2.7 mmHg; P = .001). The mean CCT of POAG eyes with an IOP of ≤ 21 mmHg was 528 ± 26 μm, and that of POAG eyes with an IOP ≥ 22 mmHg was 531 ± 37 μm; these values were not significantly different from that of nonglaucomatous eyes (530 ± 31 μm; P = .943 and .996, respectively). CONCLUSIONS The prevalences of POAG and POAG with an IOP ≤ 21 mmHg in the Namil-myon region of central South Korea were higher than that in most previous reports worldwide, but were similar to the reported rates in black and Japanese populations. The mean IOP of POAG eyes was higher than nonglaucomatous eyes, but the mean CCTs were not different. FINANCIAL DISCLOSURE(S) The authors have no proprietary or commercial interest in any of the materials discussed in this article.

Structure–Function Relationship and Diagnostic Value of Macular Ganglion Cell Complex Measurement Using Fourier-Domain OCT in Glaucoma

PURPOSE To assess the relationship between visual function and macular ganglion cell complex (GCC) thickness measured by Fourier-domain optical coherence tomography (OCT) and to evaluate the diagnostic value of GCC thickness for detecting early, moderate, and severe glaucoma. METHODS Participants underwent reliable standard automated perimetry testing and OCT imaging with optic nerve head (ONH) mode and GCC mode within a single day. The relationship between structure and function was evaluated by comparing GCC thickness with mean deviation (MD) and visual field index (VFI), by regression analysis. The results were compared with those obtained for retinal nerve fiber layer (RNFL) thickness. The area under the receiver operating characteristic curve (AUC) was used to determine the relationship between disease severity and glaucomatous changes in RNFL and GCC parameters. RESULTS One hundred three normal control subjects and 138 patients with glaucoma were included in the present study. Compared with linear models, second-order polynomial models better described the relationships between GCC thickness and MD (P<0.001), and between GCC thickness and VFI (P<0.001). A GCC pattern parameter, global loss volume (GLV), had the highest AUC for detecting early glaucoma. The AUC of mean GCC thickness for early glaucoma was higher than that of mean RNFL; however, the difference was not significant (P=0.330). CONCLUSIONS A curvilinear function best described the relationship between VF sensitivity and GCC thickness. Macular GCC thickness and RNFL thickness showed similar diagnostic performance for detecting early, moderate, and severe glaucoma.

Agmatine: clinical applications after 100 years in translation.

Agmatine (decarboxylated arginine) has been known as a natural product for over 100 years, but its biosynthesis in humans was left unexplored owing to long-standing controversy. Only recently has the demonstration of agmatine biosynthesis in mammals revived research, indicating its exceptional modulatory action at multiple molecular targets, including neurotransmitter systems, nitric oxide (NO) synthesis and polyamine metabolism, thus providing bases for broad therapeutic applications. This timely review, a concerted effort by 16 independent research groups, draws attention to the substantial preclinical and initial clinical evidence, and highlights challenges and opportunities, for the use of agmatine in treating a spectrum of complex diseases with unmet therapeutic needs, including diabetes mellitus, neurotrauma and neurodegenerative diseases, opioid addiction, mood disorders, cognitive disorders and cancer.

Comparing the ganglion cell complex and retinal nerve fibre layer measurements by Fourier domain OCT to detect glaucoma in high myopia

Aim To compare the diagnostic ability to detect glaucomatous changes between peripapillary retinal nerve fibre layer (RNFL) thickness and the macular ganglion cell complex (GCC) in highly myopic patients using Fourier domain optical coherence tomography. Methods Participants, consecutively enrolled from January 2009 to June 2009, were imaged with RTVue-100 (NHM4 and MM7 scan). The sensitivity and specificity of a colour code less than 5% (red or yellow) for glaucoma diagnosis were calculated. Area under the receiver operator characteristic (AUROC) curves were generated to assess the ability of each parameter to detect glaucomatous changes. Results 73 normal controls and 77 glaucoma patients were included. Participants were categorised as 105 non-high myopes (spherical equivalent >−6.0 dioptres) and 45 high myopes (Spherical equivalent ≤−6.0 dioptres). The GCC thickness showed a strong correlation with RNFL thickness (correlation coefficient=0.763, p<0.001) in all participants. The sensitivity from superior GCC colour code was significantly higher than that from superior RNFL (p=0.019). The ability to detect glaucomatous changes in the highly myopic group by examining the average GCC thickness (AUROC, GCC; 0.889) was higher than when examining RNFL thickness (AUROC, RNFL; 0.825); however, there was no statistical significance (p=0.442). Conclusions The ability to diagnose glaucoma with macular GCC thickness was comparable with that with peripapillary RNFL thickness in high-myopia patients. Macular GCC thickness measurements may be a good alternative or a complementary measurement to RNFL thickness assessment in the clinical evaluation of glaucoma in patients with high myopia.

Spectral-Domain Optical Coherence Tomography for Detection of Localized Retinal Nerve Fiber Layer Defects in Patients With Open-Angle Glaucoma

OBJECTIVE To evaluate and compare time-domain (Stratus) and spectral-domain (Cirrus; both Carl Zeiss Meditec, Dublin, California) optical coherence tomography (OCT) for the detection of localized retinal nerve fiber layer (RNFL) defects in patients with open-angle glaucoma. METHODS Patients with localized RNFL defects and age-matched normal control participants were consecutively enrolled from July 1 to December 31, 2008. Sixty-six eyes from 66 patients and 66 eyes from 66 normal controls were imaged with Stratus OCT (fast RNFL scan mode) and Cirrus OCT (optic disc cube mode). The ability to detect the RNFL defect by using quadrant clock-hour maps from both OCTs and a Cirrus OCT deviation map were compared with red-free RNFL photography, which is the criterion standard for visualizing RNFL defects. RESULTS The Cirrus OCT deviation map exhibited significantly higher overall sensitivity (92.42%) in detecting the RNFL defects compared with the other maps, which were derived from a 3.46-mm-diameter peripapillary cross-sectional RNFL scan of both OCTs (P < .001). The Cirrus OCT quadrant map had a higher specificity; however, it was not statistically significant (P = .07). Compared with the other maps, the Cirrus OCT derivation map had the lowest cutoff angle for the width (10.69°) of the RNFL defect. CONCLUSIONS The deviation map from Cirrus OCT was more sensitive in detecting RNFL defects than the clock-hour and quadrant maps derived from cross-sectional peripapillary RNFL measurements by Stratus and Cirrus OCTs. The ability to detect localized RNFL defects on clock-hour or quadrant RNFL maps did not significantly differ between Stratus OCT and Cirrus OCT.

Comparison of TGF-β1 in Tears Following Laser Subepithelial Keratomileusis and Photorefractive Keratectomy

PURPOSE To compare the release of tear fluid transforming growth factor-beta1 (TGF-beta1) of 15 patients who underwent photorefractive keratectomy (PRK) in one eye and laser subepithelial keratomileusis (LASEK) in the other eye. METHODS Tear fluid samples were collected with scaled microcapillary tubes preoperatively (day 0) and on the first, second, and seventh postoperative days. We calculated the release of TGF-beta1 (tear fluid flow-corrected concentrations of TGF-beta1) by multiplying the concentration by capillary tear fluid flow and also evaluated corneal haze at 1, 3, and 6 months after PRK or LASEK. RESULTS The median TGF-beta1 release values were: Day 0: 50.6 pg/min (range 0 to 101.6 pg/min) for PRK and 56.7 pg/min (range 0 to 121.8 pg/min) for LASEK (P=.496); Day 1: 240.6 pg/min (range 56.6 to 1120.2 pg/min) for PRK and 155.2 pg/min (range 45.1 to 480.4 pg/min) for LASEK, which showed a significant difference between the two procedures (P=.041); Day 2: 395.7 pg/min (range 92.3 to 1150.7 pg/min) for PRK and 185.2 pg/min (range 41.4 to 872.5 pg/min) for LASEK (P=.004); and Day 7: 91.3 pg/min (range 0 to 225.4 pg/min) for PRK and 74.3 pg/min (range 0 to 187.1 pg/min) for LASEK, (P=.244). The mean corneal haze score at 1 month after PRK was 0.88 +/- 0.50 and 0.53 +/- 0.29 after LASEK, and a statistically significant difference was noted between the two groups (P=.005). At 3 months (P=.083) and 6 months (P=.157) after the procedures, there were no statistically significant differences. CONCLUSIONS A lower amount of tear fluid transforming growth factor-beta1 was released in the early postoperative days following LASEK than in PRK. The lower grade of corneal haze seen in LASEK than PRK in the early postoperative period may come from a decreased release of TGF-beta1, which may have a role in wound healing.

Factors Associated with False Positives in Retinal Nerve Fiber Layer Color Codes from Spectral-Domain Optical Coherence Tomography

PURPOSE To determine the factors that contribute to false-positive retinal nerve fiber layer (RNFL) color code results from spectral-domain optical coherence tomography (OCT). DESIGN A prospective, cross-sectional study. PARTICIPANTS This study included 149 eyes from 77 healthy participants. METHODS Participants, who were consecutively enrolled from June 2009 to December 2009, underwent Cirrus OCT. Recorded demographic and clinical factors included age, gender, eye side, intraocular pressure, central corneal thickness, spherical equivalent, axial length, anterior chamber depth, disc area, and the extent of retinal vasculature. MAIN OUTCOME MEASURES An abnormal finding in RNFL color codes was defined as ≥1 yellow or red sectors by quadrant and clock-hour maps and a wedge-shaped color pattern represented by yellow or red in the deviation map. The incidence of false-positive color codes was determined. The influence of clinical and demographic factors on the incidence of false-positive RNFL color codes was assessed using generalized linear mixed model analysis. RESULTS The false-positive rate for ≥1 of the quadrant, clock-hour, and deviation maps was 26.2%. Longer axial length and smaller disc area were significantly associated with an increased incidence of false-positives when other factors were controlled (odds ratios, 2.422 and 0.165; P = 0.008 and 0.035, respectively). CONCLUSIONS The factors that significantly affected the false-positive RNFL color code results using spectral-domain OCT were axial length and disc area, which may significantly affect the specificity of spectral-domain OCT. Therefore, axial length and disc area should be considered during RNFL thickness profile analysis.

Agmatine protects retinal ganglion cells from hypoxia-induced apoptosis in transformed rat retinal ganglion cell line

BackgroundAgmatine is an endogenous polyamine formed by the decarboxylation of L-arginine. We investigated the protective effects of agmatine against hypoxia-induced apoptosis of immortalized rat retinal ganglion cells (RGC-5). RGC-5 cells were cultured in a closed hypoxic chamber (5% O2) with or without agmatine. Cell viability was determined by lactate dehydrogenase (LDH) assay and apoptosis was examined by annexin V and caspase-3 assays. Expression and phosphorylation of mitogen-activated protein kinases (MAPKs; JNK, ERK p44/42, and p38) and nuclear factor-kappa B (NF-κB) were investigated by Western immunoblot analysis. The effects of agmatine were compared to those of brain-derived neurotrophic factor (BDNF), a well-known protective neurotrophin for retinal ganglion cells.ResultsAfter 48 hours of hypoxic culture, the LDH assay showed 52.3% cell loss, which was reduced to 25.6% and 30.1% when agmatine and BDNF were administered, respectively. This observed cell loss was due to apoptotic cell death, as established by annexin V and caspase-3 assays. Although total expression of MAPKs and NF-κB was not influenced by hypoxic injury, phosphorylation of these two proteins was increased. Agmatine reduced phosphorylation of JNK and NF-κB, while BDNF suppressed phosphorylation of ERK and p38.ConclusionOur results show that agmatine has neuroprotective effects against hypoxia-induced retinal ganglion cell damage in RGC-5 cells and that its effects may act through the JNK and NF-κB signaling pathways. Our data suggest that agmatine may lead to a novel therapeutic strategy to reduce retinal ganglion cell injury related to hypoxia.

Agmatine protects cultured retinal ganglion cells from tumor necrosis factor-alpha-induced apoptosis

AIMS We investigated the protective effects of agmatine against tumor necrosis factor (TNF)-alpha-induced apoptosis in transformed rat retinal ganglion cells (RGC-5 cell line). MAIN METHODS The RGC-5 cells were exposed to 50 ng/mL TNF-alpha for 48 h with or without presence of 100 microM agmatine as indicated. Cell viability was determined by lactate dehydrogenase (LDH) assay. Double staining with Hoechst 33342 and propidium iodide for morphological analysis was performed. Subsequently, using annexin V assay, the proportion of cells actively undergoing apoptosis was determined. KEY FINDINGS After 48 h of exposure to 50 ng/mL TNF-alpha, 17.00% of RGC-5 cells were lost, as evident by LDH assay. TNF-alpha-induced RGC-5 cell death was reduced to 8.14% with 100 microM agmatine treatment. This observed cell loss was due to apoptotic cell death, as established by annexin V assay. SIGNIFICANCE Our results reveal that agmatine has neuroprotective effects against TNF-alpha-induced apoptosis in retinal ganglion cells in vitro.