Showing papers by "Tae Wan Kim published in 2015"

Bilateral sequential optic neuritis in Behçet's syndrome.

Abstract: Dear Editor, Optic neuritis is the most common inflammatory optic neuropathy affecting young adults [1]. Less commonly, optic neuritis may be associated with systemic autoimmune disease, of which Behcet's syndrome is an extremely rare cause, with only 20 identified cases to date [2]. To the best of our knowledge, there have been no reports in Korean patients. Herein, we report a patient presenting with bilateral sequential optic neuritis who was finally diagnosed with Behcet's syndrome. 30-year-old man visited the outpatient clinic for headache, periocular pain, and scotoma in his left eye. The symptom had developed over a period of several hours. He had no remarkable medical history, except experience of similar symptoms in his right eye about one year prior. Brain magnetic resonance imaging, cerebrospinal fluid tapping, and all markers for infectious diseases showed normal results. On ophthalmologic examination, his best corrected visual acuity was 20 / 20 in both eyes, and the anterior segments were normal in both eyes. Small central scotoma was noticed from Goldmann perimetry in both eyes. The left disc was swollen (Fig. 1A), and a small pigment epithelial detachment was found in his left eye on optical coherence tomography. We commenced treatment with intravenous methylprednisolone at a dose of 125 mg four times a day for three days. On the last day of steroid pulse therapy, the papillitis on the left eye had resolved fully. Fig. 1 Fundus photographs showing the clinical course of the patient. (A) Fundus photograph of the left eye showing severe disc swelling. (B) Fundus photograph of the right eye during the second episode showing disc swelling with a granulomatous lesion at the ... Two years later, he revisited our clinic for blurred vision and pain with movement in the right eye. His best corrected visual acuities were 20 / 30 in right eye and 20 / 20 in left eye. Slit lamp examination showed a trace amount of cells in the anterior chamber of both eyes. Fundus examination disclosed a granulomatous lesion on the inferotemporal border of the right disc (Fig. 1B), mild disc swelling of the right eye, and dot opacities in the mid-peripheral retina in the left eye (Fig. 1C). Fluorescein angiography demonstrated mild vessel sheathing with definite venous beadings in both eyes (Fig. 1D and 1E). On more detailed history taking, the patient described several oral ulcers and pustular skin lesions on his legs, which had continued for several months. The pathergy test demonstrated positive results. As he fulfilled more than two of the four hallmark symptoms which are recurrent genital ulcerations, eye involvement, skin lesions, and a positive pathergy test, he was diagnosed with Behcet's disease. We started intravenous methylprednisolone 1 g daily for five days. One week after discharge, the best corrected visual acuity of his right eye recovered to 20 / 20. Both anterior chambers were clear, and no disc edema was detected. He continued taking oral methylprednisolone, which was gradually tapered over six weeks. On the last follow-up visit, his best corrected visual acuities were 20 / 20 in right eye and 20 / 30 in left eye, and all examination results were unremarkable. This case demonstrates recurrent episodes of acute optic neuritis involving both eyes in Behcet's syndrome. Although primary optic neuropathy is exceedingly rare in Behcet's patient, the possibility of Behcet's syndrome as an underlying cause of optic neuritis should be considered. As Behcet's syndrome is a chronic, relapsing, and occlusive vasculitis disease, lifelong immunosuppressive treatment is needed in order to prevent recurrence of neurological and ophthalmic complications [3].

Bilateral macula-involving metastatic infection resulting from septic embolization.

Abstract: Dear Editor, Retinal features associated with septicemia usually do not involve the macula. However, there have been a small number of reports regarding macular hole cases secondary to septic emboli [1,2]. We report a case of bilateral macula-involving metastatic infection rather than macular hole resulting from septic embolization. A 29-year-old man who had initially presented to the emergency room for altered mentality and been diagnosed with gram-positive cocci bacteremia and meningoencephalitis after work-up was referred for decreased bilateral vision, noted about 3 days after admission. Methicillin-sensitive Staphylococcus aureus was observed on blood culture. The patient began a 4-week course of intravenous penicillin G (4 million units every 4 hours). On initial examination, his best-corrected visual acuities (BCVA) were 20 / 40 in right eye and 20 / 100 in left eye. Fundus examination showed small white infiltration with hemorrhage in the juxtafovea of both eyes (Fig. 1A). Fluorescein angiography showed no active leakage (Fig. 1B). Spectral domain-optical coherence tomography images showed disruption at the junction of the photoreceptor inner and outer segments (IS/OS) junction and cone outer segment and hyperreflective intraretinal deposits involving both the inner and outer retinal layers at the fovea (Fig. 1C). The area of IS/OS junction and cone outer segment layer disruption was much wider and more extensive in the left eye, in which there was also a focal area of near total retinal tissue defect close to the shape of an impending macular hole in the juxtafovea of the left eye (Fig. 1D). Fig. 1 Fundus images showing the clinical course of the patient. (A) Small white infiltrations with hemorrhage were present in the juxtafovea of both eyes. (B) Fluorescein angiography showed no active leakage. (C) Spectral domain-optical coherence tomography ... On the second visit 2 weeks after appropriate intravenous antibiotic therapy, his BCVA had improved to 20 / 22 in right eye and 20 / 30 in left eye. Fundus examination showed complete resolution of the hyperreflective intraretinal deposits in both eyes (Fig. 1E). Spectral domain-optical coherence tomography showed near full restoration of the previously disrupted IS/OS junction and cone outer segment lines except for a small focal defect of the IS/OS junction in the left eye. The hyperreflective intraretinal deposits in both eyes were no longer present (Fig. 1F). Three months later, his BCVA were 20 / 20 in right eye and 20 / 40 in left eye; however, the focal defect of the IS/OS junction in the left eye was nearly unchanged, and the continuity of each retinal layer remained incomplete. Although the incidence of macula-involving metastatic infection secondary to bacterial septic embolism is rare, careful observation is required when performing fundus examination for possible metastatic infection in bacteremia patients. Metastatic septic emboli may involve both the outer and inner retinal layers at the bilateral fovea and may cause a near total retinal tissue defect close to that of an impending macular hole. Our case showed that a macula-involving metastatic infection can involve reversible retinal structural change with no functional sequelae and improvement of visual acuity after suitable antibiotic therapy.

An Analysis of the Effects of Walking Guidance System in Subway Stations using Genetic Algorithm

Abstract: The conflict of opposing pedestrian traffic-flow in a subway station(made up of stair, passageway, and escalator) diminishes the convenience and mobility of its users. In addition, the station’s efficiency would be negatively affected by the growth of delay and queue length in pedestrian facilities. As these phenomena have been resulted by the overlapping in pedestrian’s traffic-line, the separation of it would alleviate these problems. For the criteria and methodology of separation, this paper has investigated the bi-directional queue length and delay on the entrance of each facility (stair, passageway and escalator). Since the pedestrian flow exists bidirectionally, we have used the weighted average by inflow rate for the delay value. For the optimization of the separation, the Genetic Algorithm has been utilized in order to minimize the delay.