레이저 각막두께측정계 각막형태검사와 초음파를 이용한 각막두께측정비교

최시환,김정훈,한남수,조영준,이성복,Si Hwan Choi,Jeong Hoon Kim,Nam Su Han,Young Joon Jo,Seong Bok Lee 대한안과학회 2006 대한안과학회지 Vol.47 No.1

Purpose: To investigate the accuracy and reproducibility of Optical Low Coherence Reflectometry (OLCR) corneal thickness measurements compared with the Orbscan system and ultrasound pachymeter (IOPac, Mentor). Methods: Two examiners measured corneal thicknesses of 78 normal eyes and in 36 eyes that had undergone LASIK, and five sequential measurements of corneal thickness with OLCR, Orbscan system, Mentor, and IOPac were performed. Remeasurements of corneal thickness in 24 normal eyes were performed after two days to investigate intra-examiner reproducibility. Results: The average corneal thickness measured in normal subjects was 536.3±23.8 ?m in OLCR, 542.4±25.3 ?m in the Orbscan system, 535.4±23.7 ?m in Mentor, and 534.2±24.1 ?m in IOPac. The average corneal thickness measured in patients who had undergone LASIK was 487.3±30.8 ?m in OLCR, 492.5±36.5 ?m in the Orbscan system, 487.5±30.8 ?m in Mentor, and 485.3±30.8 ?m in IOPac. There was no statistically significant difference between the four pachymeters. The inter-examiner and intra-examiner reproducibilities were shown to be highly reliable. Conclusions: The OLCR showed similar measurments of corneal thickness with the Orbscan system and ultrasound pachymeter, and showed no difference in reproducibility with different examiners.

토안에서 금판 삽입술의 효과

최시환,박영규,박우찬 충남대학교 의과대학 지역사회의학연구소 1993 충남의대잡지 Vol.20 No.1

Lagophthalmos can result in serious keratopathy because of corneal exposure and inadequate lacrimation. Four patients underwent gold plate insertion to rehabilitate paralysis of the eyelid caused by facial nerve palsy. Gold plate insertion resulted in exellent eyelid closure, protection, and cosmesis. There were no infections or extrusions. Lagophthalmos and exposure keratitis were resolved or were significantly improved in these patients. In selected patients this technique reestablishes a voluntary blink and provides corneal protection without the limitation of tarsorrhaphy. Gold plate insertion has become the procedure of choice for eyelid rehabilitation.

초자체 출혈에 있어서 조직형 플라스미노젠 활성제의 효능

최시환 충남대학교 의과대학 지역사회의학연구소 1990 충남의대잡지 Vol.17 No.1

Tissue plasminogen activator(tPA) is a fibrin-specific fibrinolytic agent that has recently been shown to be effective in accelerating the clearance of hyphema. Intravitreal injection of tPA can promote repid lysis of experimental intravitreal fibrin clots. The purpose of this study was to investigate the efficacy of intravitreal tPA injection for the treatment of vitreous hemorrhage in the phakic non-vitrectomized rabbit eyes. Vitreous hemorrhages were produced by intravitreal injections of 0.55ml of autologous whole blood in twenty-five rabbit eyes with intact vitreous. The injection of 25 or 100 microgram of tPA in fifteen eyes resulted in the clearance of vitreous hemorrhage in 99±19 or 34±6.5 days respectively. This was significantly faster than control eyes in which the clearance was not seen until 131±17 days later. No tractional retinal datachment was observed.

단안 안검봉합에 의한 병아리 안구크기의 변화

최시환,김세윤,서병로,민병무 충남대학교 의과대학 지역사회의학연구소 1991 충남의대잡지 Vol.18 No.2

In an attempt to elucidate the eyeball enlargement by eyelid suture, two-day old white Leghorn chickens (n=20) were lightly anesthetized with ether and monocular upper and lower eyelids were sutured together with 6-0 black silk. The other eye was used as control group. Refractive error, corneal curvature, or axial length by ultrasonography were assessed before the study, and 3 weeks and 6 weeks after lid suture. Dimensional changes, intraocular pressure, and weight of enucleated eyeball were measured at 6 weeks. The results of the study were as follows: 1. The eyelid sutured group developed significant axial elongation (11.00±0.36mm vs 10.69±0.24mm, mean±SD, by ultrasonography; 12.57±0.66mm vs 12.02±0.41mm by micrometer), equatorial length (15.48±0.45mm vs 15.32±0.48mm), and weight (1.51± 0.12g vs 1.39±0.09g) in comparison with control group. 2. Corneal sag and diameter, intraocular pressure, and refractive error were not significantly different between both groups. Our results support the hypothesis that form-vision deprivation induces the enlargement of eyeball, especially the posterior segment of the eyeball.

각막공여를 위한 굴절교정수술 여부의 식별

최시환,이연희,윤여민,이재림,Si-Hwan Choi,M,D,Yeon-Hee Lee,M,D,Yie-Min Yun,M,D,Jae-Lim Lee,M,D 대한안과학회 2005 대한안과학회지 Vol.46 No.2

Purpose: To provide fundamental data for screening for prior refractive surgery in donor cornea. Methods: The corneal curvature map and pachymetric measurements were analyzed in 68 eyes that had undergone corneal refractive surgery. Differences in the corneal curvature of the center and periphery, differences in the corneal thickness of the center and periphery, and the shape factor on the curvature map in postoperative eyes were compared with preoperative measurements. Results: Measurement of the central corneal curvature subtracted from the peripheral corneal curvature was -1.64±0.71D in the preoperative eyes and 3.10±1.68D in the postoperative eyes. With a criterion of -0.23D, the sensitivity and specificity were 100% and 98.5%, respectively. The shape factor was 0.24±0.09 in the preoperative eyes and -0.82±0.45 in the postoperative eyes. With a criterion of 0.058, the sensitivity and specificity were both 100%. Measurement of the central corneal thickness subtracted from the peripheral corneal thickness was 97.60±25.42 ?m in the preoperative eyes and 163.47±38.5 ?m in the postoperative eyes. With a criterion of 123.0 ?m, the sensitivity and specificity were 89.7% and 88.4%, respectively. Conclusions: Regional differences in corneal curvature and shape factor may be very useful parameters in screening for prior refractive surgery in donor cornea. The difference in corneal thickness may also be a useful parameter.

각막형태검사법을 이용한 각막양상과 눈의 굴절력과의 관계

최시환,민병무,김용백,김창식,안승일 충남대학교 의과대학 지역사회의학연구소 1998 충남의대잡지 Vol.25 No.1

We evaluated the topography of 200 normal cornea of Korean. The mean age was 37 years and mean refractive astigmatism was 0.82±0.69D. The corneal patterns were classified by Dr. Bogan such as round, oval, symmetric bow tie, asymmetric bow tie, and irregular pattern. Its incidence was 14.0%, 11.0%, 16.0%, 30.0% and 29.0%, respectively. There was no statistically significant difference in the distribution of topographic pattern in male and female and among age groups. The symmetric bow tie type had the greatest spherical equivalent and astigmatism and there was no statistically significant difference in those two values between round and oval group. Two bow-tie groups were not also statistically significantly different from each other in spherical equivalent and astigmatism. However, two bow tie groups were significantly different from round and oval group. So, it was possible to divide corneal topographic pattern into three groups such as round and oval, two bow tie, and irregualr group. We could understand normal corneal status related to corneal pattern and refractive power through this qualitative system for classifying corneal topography.

한국 각막이식의 실태

최시환,이양원,김효명,양선모,홍종욱,윤경철,정의상,차흥원,진경현,조희태,주천기,김응권,신경환,이도형,최태훈,이종수,김완수,허준,위원량,김미금,이상범,김재찬,김형준,이형근,김재덕,박우찬,정성근,윤태중 대한안과학회 2006 대한안과학회지 Vol.47 No.4

Purpose: To report an epidemiologic study of keratoplasty in which we analyze basic data of corneal transplants and corneal donations in Korea. Methods: From June 2004 through October 2004, questionnaires were distributed to 25 hospitals. The questionnaires were about the characteristics of patients registered in eye banks for keratoplasty from May 2001 to April 2003, and about the results of keratoplasties performed from May 2002 to April 2003. Results: The leading corneal diseases in patients registered for keratoplasty were infectious keratitis (22.0%), trauma (21.0%), and pseudophakic and aphakic bullous keratopathy (13.8%), in that order. The leading indications in corneal recipients were: trauma (15.5%), pseudophakic and aphakic bullous keratopathy (13.7%), and infectious keratitis (10.7%), in that order. In 233 cases of keratoplasties, penetrating keratoplasty was performed in 229 cases (98.3%) and lamellar keratoplasty was performed in 4 cases (1.7%). The most common combined surgery was cataract extraction. Common causes of graft failure were rejection of donor cornea and infection. Imported donor corneas were used in sixty-one cases (26.2%) among the 233 total keratoplasties. Conclusions: We constructed an epidemiologic data base of patients registered for keratoplasty, corneal donation, and the results of keratoplasties throughout Korea.

두가지 눈추적장치를 사용한 라식 후 중심이탈의 분석

최시환,이연희,김진하,Si-Hwan Choi,Yeon-Hee Lee,Jin-Ha Kim 대한안과학회 2005 대한안과학회지 Vol.46 No.3

Purpose: To evaluate the efficacy of two excimer laser systems with eye-tracker in the term of decentration amount. Methods: We performed LASIK with LaserScan LSXTM (group 1, 39 eyes) and Allegretto WaveTM (group 2, 94 eyes), both of which were equipped with eye-tracker. The amount of decentration was measured on a difference map that was obtained from preoperative and postoperative corneal topography, and was compared between the two groups. Results: The amount of decentration was significantly higher in group 1 (0.39±0.22 mm) than in group 2 (0.29±0.18 mm) (p=0.018). When these groups were subdivided by preoperative spherical equivalent, in case of under -6.0 D, the amount of decentration between the two groups (0.31±0.16 mm in group 1, 0.28±0.15 mm in group 2, p=0.380), whereas in case of over -6.0 D, the amount of decentration was significantly higher in group 1 (0.48±0.26 mm) than in group 2 (0.30±0.21 mm) (p=0.020). Conclusions: Allegretto WaveTM showed better centration ability than LaserScan LSXTM and this superiority was more profound in highly myopic eyes.

웨이브프론트의 연속 측정방법으로 분석한 눈물막의 불안정성에 따른 고위수차 변화

최시환,신용일 대한안과학회 2012 대한안과학회지 Vol.53 No.8

Purpose: To evaluate the changes of higher order aberration according to tear-film instability measured serially by KR-1W wavefront every second for 10 seconds. The present study also analyzed the relationship between higher order aberration and the tear-film break-up time, Schirmer test, and superficial punctate keratitis. Methods: The 228 eyes of 114 patients randomly selected from patients who visited hospital were measured once every second for 10 seconds after eye blinking by continuous measurement using wavefront. Results: Higher order aberration increased overtime, and the higher order aberration value measured at the tenth second subtracted from the value of the first second was statistically significant (p = 0.004). In addition, the increment in higher order aberration between 9 seconds and 10 seconds was statistically significant (p = 0.01). The group of patients with a tear-film break-up time less than 6 seconds showed the greatest changes when measuring the higher order aberration difference value between the tenth and first seconds, which was statistically significant (p = 0.002). The group of patients where the Schirmer test results were longer than 10 millimeters and who had superficial punctate keratitis showed the greatest statistically significant changes when measuring the difference in higher order aberration values between the tenth and first seconds (p = 0.008, p = 0.005, respectively). Conclusions: Analysis of higher order aberration by wavefront could be useful in cases of decreased optical quality, diagnosis and evaluation of treatment in dry eye syndrome. J Korean Ophthalmol Soc 2012;53(8):1076-1080

안구길이, 수정체전낭-망막길이, 굴절상태 및 각막굴절력간의 상호관계

최시환,박주희,박우찬 충남대학교 의과대학 지역사회의학연구소 1992 충남의대잡지 Vol.19 No.2

Axial length is major determinant of ocular refractive power. The purpose of this study was to establish the interrelationship among axial length, anterior lens capsule to retina length(ACRL), refractive states, and corneal refractive power. We measured above four variables of 364 normal adult eyes. The results were as follows: 1. The mean axial length and ACRL of all 364 eyes were 24.93(±1.25mm) and 21.59(±1.20mm) respectively. 2. The mean axial length and ACRL of 63 eyes within ±1 diopter were 23.64(±0.82mm) and 20.34(±0.79mm) respectively. 3. Refractive states, axial length, and ACRL were closely associated. The coefficient of correlation between refractive states and axial length is r=-0.7542(p<0.001), the one between refractive states and ACRL is r=-0.7526(p<0.001). 4. The coefficient of correlation between corneal refractive power and axial length is r=-0.3589(p<0.001), the one between corneal refractive power and ACRL is r=-0.3727(p<0.001). 5. Axial length/ACRL ratio of 63 eyes within ±1 diopter is 1.16(±0.02).