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Dive into the research topics where Hongseok Yang is active.

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Featured researches published by Hongseok Yang.


Retina-the Journal of Retinal and Vitreous Diseases | 2009

A prospective study of blood pressure and intraocular pressure changes in hypertensive and nonhypertensive patients after intravitreal bevacizumab injection.

Kihwang Lee; Hongseok Yang; Hunsub Lim; Ho Min Lew

Purpose: To evaluate the changes in blood pressure and intraocular pressure (IOP) in patients with and without hypertension after intravitreal bevacizumab (Avastin) injection. Methods: This study examined 135 (74 nonhypertensive vs. 61 hypertensive) consecutive patients treated with an intravitreal injection of 1.25 mg bevacizumab for retinal vascular diseases prospectively over a 6-month period. All the hypertensive patients were on medication, and only patients with controlled hypertension after consultation with cardiology specialists were included. Intraocular pressure and blood pressure were measured before and 30 minutes, 1 day, 1 week, 3 weeks, and then every month after the bevacizumab injection. Results: The mean baseline systolic and diastolic pressures were significantly higher in the hypertensive group (systolic P = 0.001, diastolic P = 0.023). None of the systolic and diastolic values after injection differed significantly from the baseline values in the hypertensive group. By contrast, the 30-minute systolic values were significantly higher than baseline (P < 0.05), and the 1-day diastolic values were lower than before injection in the nonhypertensive group (P < 0.05). The mean baseline IOP of the nonhypertensive and hypertensive groups was similar (P = 0.08). The mean IOP 30 minutes after injection was significantly higher than the baseline mean IOP (P < 0.05), and the mean IOPs at 1 day and 1 week were significantly lower than before injection in both groups (P < 0.05). Conclusion: Intravitreal bevacizumab injection is safe in terms of blood pressure and IOP in both hypertensive and nonhypertensive patients after 6 months of follow-up.


Current Eye Research | 2012

Protective Effect of Grape Seed Extract against Oxidative Stress-Induced Cell Death in a Staurosporine-Differentiated Retinal Ganglion Cell Line

Hongseok Yang; Bo Kyung Lee; Koung Hoon Kook; Yi-Sook Jung; Jaehong Ahn

Objective: Grape seed extract (GSE) is a potent antioxidant. We examined the effect of GSE on oxidative stress-induced cell death in a transformed retinal ganglion cell line, RGC-5. Methods: Staurosporine-differentiated RGC-5 (ssdRGC-5) cells obtained by treating RGC-5 cells with 1 µM staurosporine were incubated with GSE for 2 h and then exposed to buthionine sulfoximine plus glutamate (B/G) for 24 h. Cell death was detected using the LIVE/DEAD viability assay and the type of cell death was evaluated using fluorescein isothiocyanate-conjugated Annexin–V/propidium iodide staining. To investigate the mechanism underlying cell death, we determined the caspase-3 activity and level of reactive oxygen species (ROS) formation. Results: Treatment of ssdRGC-5 cells with B/G increased intracellular ROS and induced apoptosis (not necrosis) with increasing caspase-3 activity. GSE rescued the ssdRGC-5 cells from oxidative stress-induced cell death by inhibiting both intracellular ROS production and caspase-3 activation. Conclusion: GSE had a neuroprotective effect against oxidative stress-induced apoptotic death in ssdRGC-5 cells.


Current Eye Research | 2014

Antifibrotic Effect of Pirfenidone on Human Pterygium Fibroblasts

Kihwang Lee; Sun Young Lee; So Yean Park; Hongseok Yang

Abstract Objective: The effects of pirfenidone were investigated on cultured human pterygium fibroblasts (HPFs). Methods: HPFs were obtained from pterygium surgery and subjected to primary culture. After treatment with 0.5, 1.0 or 1.5 mg/mL pirfenidone, MTT and cell migration assays were performed, and procollagen secretion and TGF-β expression were measured by Western blotting and immunofluorescence analysis. Results: Pirfenidone had a significant inhibitory effect on HPF proliferation, migration and collagen synthesis. There were no differences between the cells treated with 0.5, 1.0 and 1.5 mg/mL pirfenidone and the controls in the MTT assay. After 48 h of treatment with 1.0 or 1.5 mg/mL pirfenidone, TGF-β expression was significantly decreased. Conclusions: These findings demonstrate that pirfenidone inhibits the proliferation, migration and procollagen secretion of HPFs at nontoxic concentrations by decreasing TGF-β expression. Thus, pirfenidone may be considered as a safe adjuvant for pterygium surgery to prevent recurrence.


Journal of Cataract and Refractive Surgery | 2006

Burst-shot infrared digital photography to determine scotopic pupil diameter

Hongseok Yang; Marvin Lee; Jun Bum Kim; Jaehong Ahn

PURPOSE: To evaluate the usefulness of infrared digital photography for determining scotopic pupil size by comparing infrared digital photography with a Colvard pupillometer (Oasis Medical). SETTING: Department of Ophthalmology, Ajou University School of Medicine, Suwon, Korea. METHODS: Scotopic pupil size in 50 eyes of 25 healthy individuals was measured with a Colvard pupillometer and a digital camera (DSC‐F828) using infrared burst shots after 5 minutes of dark adaptation. Measurements were performed by 2 independent examiners (E1 and E2). The digital photograph images were read using the ruler function of Adobe Photoshop 7.0 by 2 independent readers (R1 and R2). Agreement and repeatability were analyzed using the comparison method described by Bland and Altman. RESULTS: The mean scotopic pupil diameter measured using the Colvard pupillometer was 6.69 mm ± 0.78 (SD) (E1) and 6.70 ± 0.71 mm (E2). The mean scotopic pupil diameter measured from the digital photograph images was 6.67 ± 0.75 mm (E1) and 6.66 ± 0.78 mm (E2). The mean difference between E1 and E2 with both devices was small; however, the result with the infrared digital camera was marginally smaller than with the Colvard pupillometer. The limits of agreement were –0.01 ± 0.70 mm with the Colvard pupillometer and 0.01 ± 0.20 mm with the digital photograph image. The digital photograph image showed better agreement. The coefficient of interrater repeatability was smaller for the digital photograph image (0.39) than for the Colvard pupillometer (0.70). CONCLUSIONS: Scotopic pupil measurement using an infrared digital camera with a burst shot had good agreement with the Colvard pupillometer and better repeatability. The infrared digital camera is less expensive, and pupil unrest can be overcome by taking serial images.


Canadian Journal of Ophthalmology-journal Canadien D Ophtalmologie | 2016

Hypertension as a risk factor for recurrent subretinal hemorrhage in polypoidal choroidal vasculopathy

Yoo-Ri Chung; Eoi Jong Seo; Yong Hyun Kim; Hongseok Yang; Kihwang Lee

OBJECTIVE To investigate the relationship between hypertension and recurrent subretinal hemorrhage (SRH) in eyes with polypoidal choroidal vasculopathy (PCV). DESIGN Retrospective, comparative case series. PARTICIPANTS Thirty-eight eyes of 38 patients with PCV. METHODS Ocular findings and clinical features were analyzed retrospectively in patients with PCV enrolled from January 2011 to December 2013. The patients were divided into 2 groups according to the presence of recurrent SRH after successful initial treatment (rebleeding vs nonrebleeding) and were subdivided into those with and without hypertension, based on history of hypertension, systolic blood pressure (SBP) >150 mm Hg. The relationship between hypertension and recurrent SRH was analyzed. RESULTS Thirty-eight patients (38 eyes) were included in this analysis. High SBP or history of hypertension was significantly more frequent in the rebleeding group than in the nonrebleeding group (p = 0.014). Subgroup analysis showed that mean time until recurrent SRH was significantly shorter in the hypertensive group than in the nonhypertensive group (p = 0.025). The cumulative incidence of recurrent SRH at 2 years was 43% in the hypertensive group and 20% in the nonhypertensive group. Cox regression after adjustment for age showed that hypertension was associated with a 3.9-fold greater risk of recurrent SRH (p = 0.039). CONCLUSIONS Recurrent SRH in patients with PCV was more common in hypertensive subjects. Undiagnosed hypertension should be considered when assessing the prognosis of patients with PCV.


Ophthalmologica | 2013

Comparison of Event-Based Methods Using Optical Coherence Tomography and Automated Perimetry to Detect the Progression of Glaucoma in Patients with Open-Angle Glaucoma

Marvin Lee; Hongseok Yang; Jongwan Kim; Jaehong Ahn

Background/Aims: To compare event-based methods for estimating the incidence of glaucoma progression using optical coherence tomography (OCT) and automated perimetry and to assess agreement between structural and functional tests for detecting glaucoma progression. Methods: Functional progression of glaucoma was estimated by guided progression analysis (GPA) using a Humphrey field analyzer (HFA), and structural progression was assessed by OCT and defined as the decrease in retinal nerve fiber layer thickness based on test-retest variability data of previous reports on clock-hour and quadrant maps. The level of agreement between structural and functional progression was evaluated using kappa statistics. Results: Fifty eyes of 50 patients with open-angle glaucoma were enrolled in this retrospective study. The incidence of visual field progression estimated by GPA was 18%. The occurrence of structural progression assessed by OCT ranged from 18 to 68%. The more stringent OCT progression criterion using a quadrant map showed the best agreement with HFA GPA (ĸ = 0.423) and detected perimetric progression with high specificity, while the less stringent OCT criterion considering any clock hour showed the lowest agreement with functional progression (ĸ = 0.098). Conclusion: OCT progression criteria based on test-retest variability showed moderate agreement with perimetric progression, and more stringent criteria showed better agreement with functional progression than less stringent ones.


Journal of The Korean Ophthalmological Society | 2008

The Assessment of Stereoacuity in Patients with Strabismus

Yoo-Ri Chung; Hongseok Yang; Ho Min Lew; Jong Bok Lee; Yoon-Hee Chang


Journal of The Korean Ophthalmological Society | 2007

The Effect on Outcome of Amblyopia Treatment in Children with Anisometropic Amblyopia

Seungsoo Rho; Hongseok Yang; Young-Ju Lew; Jong Bok Lee; Yoon-Hee Chang


Journal of The Korean Ophthalmological Society | 2006

Factor Influencing Anatomical Failure of Simple Rhegmatogenous Retinal Detachment

Marvin Lee; Chan-Shik Moon; Hongseok Yang; Ho Min Lew


Journal of The Korean Ophthalmological Society | 2011

Recurrence Rates of Conjunctival Autograft Transplantation With Aminiotic Membrane Transplantation in Primary Pterygium Surgery

Jong Wan Kim; Jaehong Ahn; Koung Hoon Kook; Hongseok Yang

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