고유함수전개법을 이용한 비대칭 유전체 원주공진기의 공진특성해석

류원열,민경호,장중호,전오곤,이창화,최현철 경북대학교 센서기술연구소 1998 센서技術學術大會論文集 Vol.9 No.1

The resonant frequency of the dielectric rod resonator which is surrounded by cylindrical cavity can be calculated very exactly by using eigenfunction expansion method in the concept of electric and magnetic wall from the symmetry. But if the supporter is put in the cavity, the symmetry disappears. Thus this method has some errors. In this paper, the resonant frequency of the asymmetric dielectric rod resonator was calculated by using the eigenfunction expansion method. Also, the effect of the supporter was discussed. Then we found that the resonant frequency was more affected in the case of TM mode than TE or Hybrid modes as the length of the supporter was longer.

전산화단층촬영을 이용한 아래 눈꺼풀 및 눈꺼풀 내 구조의 연령별 위치 변화에 대한 분석

류원열,고병욱,정우진,안희배,Won Yeol Ryu,Byung Uk Ko,Woo Jin Jeung,Hee Bae Ahn 대한안과학회 2010 대한안과학회지 Vol.51 No.11

Purpose: The anatomic relationships of the lower lid and soft tissue between younger and older groups were compared using CT scans for confirming the negative vector relationship in the Korean population. Methods: The study sample was composed of 100 patients with no history of previous surgery and no ocular disease. Two groups of 100 patients, younger (less than 30 years of age) versus older (above 50 years of age), were studied using CT scans. The distances from the anterior cornea to the lower lid fat, inferior orbital rim and anterior cheek mass were measured at the midpupillary plane. Results: The mean age of the younger group was 22.0 years (ages 14 through 29), compared with 60.6 years (ages 53 thru 73) for the older group. Comparison of mean linear measurements revealed an anterior movement of the lower lid fat between younger and older groups (-5.09 mm vs. -3.50 mm, respectively, P < 0.01). A regression of the inferior orbital rim (-6.93 mm vs. -8.98 mm, P < 0.01) and anterior cheek mass (3.07 mm vs. 0.43 mm, P < 0.01) was observed with age in the sagittal cross section view. Conclusions: The present study demonstrates the orbital remodeling according to age in the Korean population. Because the negative vector is more common in the elderly and portends a greater risk for lower lid complications after surgery, surgeons need to consider the orbital remodeling according to age before surgery. J Korean Ophthalmol Soc 2010;51(11):1427-1430

눈물길 협착이 없는 눈물흘림 환자에서 가쪽눈꺼풀판띠고정술과 실리콘관삽입술의 효과

류원열,서지영,안희배,Won Yeol Ryu,Ji Young Suh,Hee Bae Ahn 대한안과학회 2010 대한안과학회지 Vol.51 No.9

Purpose: To compare the effects of the lateral tarsal strip procedure alone and the lateral tarsal strip procedure combined with silicone tube intubation in the treatment of functional lacrimal duct obstruction. Methods: The present study investigated 27 eyes of 20 patients underwent lateral tarsal strip procedure (LTS) alone and 29 eyes of 18 patients underwent combined lateral tarsal strip procedure and silicone tube intubation and who were diagnosed with functional lacrimal duct obstruction. The authors retrospectively reviewed patients’ medical records for information including age, gender, history, follow‐up period, tear meniscus height (TMH), and symptoms. Results: The average age of the LTS alone group was 60.3 years, and that of the combined groups was 65.9 years. The TMHs in the LTS only and combined operation groups were 0.62 ± 0.23 mm and 0.62 ± 0.19 mm before the operation and 0.43 ± 0.20 mm and 0.26 ± 0.09 mm after the operation, respectively. The postoperative improvement in epiphora was 74.1% after the LTS alone and 86.2% after combined LTS with silicone tube intubation. The postoperative improvement in epiphora and the operative technique of the lateral tarsal strip‐canthus sparing or cantholysis were not relevant. Conclusions: Lateral tarsal strip combined with silicone tube intubation appeared useful in the treatment of epiphora patients without anatomic lacrimal duct obstruction. Determining which operative technique of lateral tarsal strip procedure should be chosen is difficult, and the preoperative syringing and snap back test may be helpful. J Korean Ophthalmol Soc 2010;51(9):1174-1178

Pattern of Extraocular Muscle Involvements in Miller Fisher Syndrome

류원열,김유환,윤별아,박환태,배종석,김종국 대한신경과학회 2019 Journal of Clinical Neurology Vol.15 No.3

syndrome (MFS) is diplopia due to acute ophthalmoplegia. However, few studies have focused on ocular motility findings in MFS. This study aimed to determine the pattern of extraocular muscle (EOM) paresis in MFS patients. Methods We consecutively recruited MFS patients who presented with ophthalmoplegia between 2010 and 2015. The involved EOMs and the strabismus pattern in the primary position were analyzed. Antecedent infections, other involved cranial nerves, and laboratory findings were also reviewed. We compared the characteristics of the patients according to the severity of ophthalmoplegia between complete ophthalmoplegia (CO) and incomplete ophthalmoplegia (IO). Results Twenty-five patients (15 males and 10 females) with bilateral ophthalmoplegia were included in the study. The most-involved and last-to-recover EOM was the lateral rectus muscle. CO and IO were observed in 11 and 14 patients, respectively. The patients were aged 59.0± 18.4 years (mean±SD) in the CO group and 24.9±7.4 years in the IO group (p<0.01), and comprised 63.6% and 21.4% females, respectively (p=0.049). Elevated cerebrospinal fluid protein was identified in 60.0% of patients with CO and 7.7% of patients with IO (p=0.019) for a mean follow-up time from the initial symptom onset of 3.7 days. Conclusions The lateral rectus muscle is the most-involved and last-to-recover EOM in ophthalmoplegia. The CO patients were much older and were more likely to be female and have an elevation of cerebrospinal fluid protein than the IO patients.

가토에서 이옥틸시아노아크릴레이트접착제와 8-0 폴리글락틴봉합사를 이용한 결막봉합법의 비교

류원열,유경원.Won-Yeol Ryu. M.D.. Kyung-Won Yoo. M.D. 대한안과학회 2005 대한안과학회지 Vol.46 No.5

Purpose: To evaluate the clinical efficacy and the histopathologic tolerance of 2-octylcyanoacrylate versus 8-0 polyglactin sutures for conjunctival wound closure in rabbits. Methods: We performed an experimental study on 16 eyes of eight New Zealand albino rabbits. Conjunctival peritomy of 8 mm was done in the superior limbus followed by extensive subconjunctival dissection in both eyes. The eyes of the rabbits were divided into two groups. The conjunctiva was then attached to the limbus again by the proposed 2-octylcyanoacrylate adhesive (left eye, Group A) or 8-0 polyglactin suture (right eye, Group B). The clinical efficacy of the closure of the conjunctival wound, either with sutures or adhesives, and the clinical and histopathologic tolerances such as hyperemia, discharge, residual adhesive or suture, inflammatory change and fibrosis were observed at 1 day and at 1, 2, 4 and 6 weeks after surgery. Two rabbits were sacrificed at each of 1, 2, 4 and 6 weeks, and specimens of their conjunctiva were examined histologically. Results: Both conjunctival surgical closure methods were found to be equally efficacious in fixing the conjunctiva to the limbus. There were no significant clinical or histopathologic tolerance differences between the two groups. The conjunctiva at 6 weeks of Group A showed nearly normalized morphology with disappeared inflammatory cells and fibroblasts, whereas those of Group B showed foreign body inflammatory reaction around the absorbing suture materials. Conclusions: 2-Octylcyanoacrylate adhesive was an efficient conjunctival closure method and was very well tolerated by the ocular surface. 2-Octylcyanoacrylate may be a possible tissue adhesive for conjunctival wound closure.

추적장치를 이용한 맞춤 라식과 굴절교정 레이저 각막 절제술의 임상 결과

류원열,이동원,박우찬,Won-Yeol Ryu,Dong-Won Lee,Woo-Chan Park 대한안과학회 2005 대한안과학회지 Vol.46 No.10

Purpose: To evaluate the safety, stability and effectiveness of the LADARVision active tracking narrow beam excimer laser system using laser in situ keratomileusis (LASIK) and photorefractive keratectomy (PRK) for the correction of spherical myopia and astigmatism. Methods: We reviewed 233 eyes that underwent LASIK (Group A: ≤-6D, Group B:> -6D) and PRK (Group C) from August 2002 to March 2003. We investigated uncorrected visual acuity (UCVA), manifest refraction, spherical equivalent, cyclotorsion, and astigmatic change before undergoing refractive surgery. The evaluation was repeated at 1 week, 1 month, 3 months, and 6 months after surgery. Results: AT one week following surgery, the mean UCVA was 1.39±0.30 in Group A, 1.25±0.34 in Group B, and 1.06±0.25 in Group C. At postoperative 6 months, the mean UCVA was 1.32±0.30, 1.09±0.16, and 1.32±0.24 in Groups A, B, and C, respectively. In all 215 eyes, cyclotorsion was 74.4%: counterclockwise, 48.4% (4.01±3.01); and clockwise, 26.0% (-4.42±3.18). The astigmatism correction rate was 79.16% in Groups A and B (LASIK groups), and 70.10% in Group C. Conclusions: The LADARVision 4000 laser yielded excellent results in myopia, with or without astigmatism and showed early refractive stability, good UCVA outcomes, and effective correction of astigmatism at 6 months postoperatively. Further studies are needed to compare custom LASIK and conventional LASIK using LADARVision.

부지법 후 발생한 안와 연조직염 환자에서 스테로이드 추가요법의 효과

류원열,박재관,안희배,Won Yeol Ryu,Jae Kwan Park,Hee Bae Ahn 대한안과학회 2011 대한안과학회지 Vol.52 No.6

Purpose: To investigate the effects of additional prednisolone treatments in orbital cellulitis after bougination. Methods: The medical records of five patients treated for orbital cellulitis after bougination were reviewed. The number of times bouginated, clinical symptoms, biopsy findings, treatment course, recurrence, and prognosis were reviewed. Results: A diffuse, erythematous mass on the lower lid around the medial canthal area was found in all patients. Bougination was performed more than twice in three patients. Chronic inflammation was checked via pathologic tissue biopsy examination in four patients. No patients receiving antibiotic treatments improved, thus additional prednisolone was used and showed satisfactory results, although recurrence was observed in two patients. The recurred two patients improved with repetitive prednisolone treatments. Conclusions: Although antibiotics are administered for the treatment of orbital cellulitis after bougination, the use of additional corticosteroids may be beneficial when inflammation is sustained. J Korean Ophthalmol Soc 2011;52(6):647-652

보험자료 빅데이터를 이용한 사시소아안과 영역에서의 연구

류원열(Won Yeol Ryu) 대한검안학회 2020 Annals of optometry and contact lens Vol.19 No.4

The exponential increasing data are generated from health care including the ophthalmology and the big data has been analyzing for being used in a variety of researches. The national health insurance covers all citizens in South Korea and claims that the data from the National Health Insurance Sharing Service (NHIS) could be useful for the research of big data. The NHIS is a data created from providing health care services that gives all of the information related to the diagnosis, treatment, cost, and personal information. Therefore, it is possible to embark on projects that was difficult to perform previously, such as researches about rare diseases targeted towards a large group of people, or the incidence and prevalence of a certain disorder, a prognosis of the treatment and complications of the epidemiological research, and its relationship with the potential risk. Even though there are some limitations of surgical and coding problems within the field of pediatric ophthalmology and strabismus, it will be possible to make it very useful. In addition, it would be able to apply it to other ophthalmological fields.

한국인의 연령 및 조도에 따른 동공크기에 대한 연구

고병욱,류원열,박우찬,Byung Uk Ko,MD,Won Yeol Ryu,MD,Woo Chan Park,MD,PhD 대한안과학회 2011 대한안과학회지 Vol.52 No.4

Purpose: To report the change of pupil sizes according to age and illuminance in the normal Korean population. Methods: Normal Koreans outpatients who never had a history of ophthalmic disease were examined. The patients consisted of 320 eyes of 160 patients, which were classified into 8 age decades (teenage to 80’s) with 40 eyes in each age group. The vertical and horizontal pupil size and area under 4 different illuminances (3,500, 1,200, 500, 5 lux) were measured using the Colvard pupillometer<sup>Ⓡ (OASIS Medical, Glendora, CA, USA). Results: The pupil size was significantly decreased as the age increased under each illuminance. The pupil area measured after dark adaptation was 47.30 mm in the teenage group, 43.32 mm in the 20’s group, 41.94 mm in the 30’s group, 40.98 mm in the 40’s group, 40.61 mm in the 50’s group, 38.60 mm in the 60’s group, 37.78 mm in the 70’s group and 35.45 mm in the 80’s group. The decrease in pupil area was statistically significant. Conclusions: In the normal Korean population, a significant decrease in pupil size and area was observed with aging. The present study results provide good basic data for cataract and presbyopia refractive surgery. J Korean Ophthalmol Soc 2011;52(4):401-406

야간혈압하강이 녹내장의 진행에 미치는 영향

서홍융,류원열,노세현,Hong Ryung Seo,Won Yeol Ryu,Sae Heun Rho 대한안과학회 2010 대한안과학회지 Vol.51 No.11

Purpose: To investigate the effect of nocturnal dip influence on the progression of glaucomatous visual field defect. Methods: We performed 24hr ABPM and V/F tests on patients diagnosed with NTG (140 patients, 280 eyes) and POAG (84 patients, 168 eyes). Nocturnal dips below 10% were classified as non-dippers, and those above 10% were noted as dippers. The correlations among nocturnal dip, progression of glaucomatous visual field defect, and hypertension treatment were examined. Results: In NTG, dippers in both systolic and diastolic blood pressure furthered glaucomatous visual field defects, with a relative risk of approximately three times that of non-dippers. Hypertension treatment was not influenced by the progression of glaucomatous visual field defect but was influenced by dips in the systolic and diastolic pressures in NTG and in diastolic pressure in POAG. Nocturnal dips were more frequent in the group with progression of the visual field compared to those in the group with non-progression of the visual field in NTG. Conclusions: Dipper caused a progression of glaucomatous visual field defects in NTG and was influenced by hypertension treatment in NTG and POAG. Performing 24hr ABPM should be helpful for glaucoma patients with progression of a glaucomatous visual field defect even when the IOP is less than the target pressure. In addition, hypertension treatment should be considered an important factor in the treatment of glaucoma. J Korean Ophthalmol Soc 2010;51(11):1471-1478