1.Clinical Results of Graft Rejection Related to Graft Size after Keratoplasty in Keratoconus.
Yoon Won MYONG ; Myong Chul SONG
Journal of the Korean Ophthalmological Society 1996;37(5):829-834
We compared the incidence of graft rejection and the rejection time after penetrating keratoplasty on the 72 keratoconus patients retrospectively between the range of 5.5 mm to 7.0 mm diameter in graft size(Group 1) and the range of 7.25 mm to 8.0 mm diameter(Group 2). The graft rejection was developed in 25 eyes(28.09%) among 89 penetrating keratoplasty patients with keratoconus. In group 1, there was graft rejection in 6 eyes(23.08%) among 26 eyes and in group 2, 19 eyes(30.16%) among 63 eyes. The rejection time of 21 eyes(84.00%) was within the first postoperative year. In group 1, graft rejections in 5 eyes(83.33%) were noted within the first postoperative year among 6 rejected eyes, and in group 2, rejections in 16 eyes(84.21%) among 19 rejected eyes. The statistical analysis showed no significant differences between the two groups in the incidence of graft rejection and rejection time(p>0.05).
Corneal Transplantation*
;
Graft Rejection*
;
Humans
;
Incidence
;
Keratoconus*
;
Keratoplasty, Penetrating
;
Retrospective Studies
;
Transplants*
2.Broken Suture after Keratoplasty.
Hyun Seung KIM ; Yoon Won MYONG
Journal of the Korean Ophthalmological Society 1996;37(2):219-224
We performed keratoplasty and did not remove suture material in 189 patients (189 eyes) after operation. Among them, 48 eyes which had clear grafts with spontaneous suture breakage had been analyzed retrospectively for the age, the sex distribution, the time and the site of broken suture, the preoperative diagnosis and the relationship between the suture breakage and the presence of vasculized recipient bed or suture method. The time when suture was broken after keratoplasty ranged from 3 months to 80 months(average 30 months). Leukoma cornea, 25 eyes(52.1%) and keratoconus, 13 eyes(27.1%) were the most common cause of keratoplasty and the others were corneal dystrophy, Fuchs dystrophy and re-keratoplasty. The most common site of broken suture was at superior quadrant(30 eyes, 62.5%), The vasculized recipient bed was found in 16 eyes, 13 eyes of leukoma cornea and 3 eyes of fe-keratoplasty in preoperative state. The statistical analysis showed significant relationship between the presence of vasculized recipient bed and the suture breakage(p<0.05). Suture was broken in 28 eyes(26.7%) of 105 eyes with single continuous suture, 6 eyes(21.9%) of 20 eyes with combined interupted suture and 14 eyes(21.9%) of 64 eyes with combined interupted and continuous suture. The statistical analysis showed no significant relationship between the suture method and the suture breakage(p>0.05).
Cornea
;
Corneal Opacity
;
Corneal Transplantation*
;
Diagnosis
;
Fuchs' Endothelial Dystrophy
;
Humans
;
Keratoconus
;
Retrospective Studies
;
Sex Distribution
;
Sutures*
;
Transplants
3.Nd:YAG Laser Effect on Corneal Curvature, Thickness and Endothelium in Rabbits.
Hak Seung KIM ; Yoon Won MYONG ; Sang Wook RHEE
Journal of the Korean Ophthalmological Society 1990;31(6):703-709
In order to evaluate the clinical application of the Nd:YAG laser(Coherent model 9900(R)) to correct the astigmatism, we observed the change in corneal curvature, thickness and endothelium after laser radiation to the rabbit cornea. The experiment composed of 14 rabbit eyes divided into two groups according to the power setting; 7 eyes of 2.5mJ group, and 7 eyes of 5mJ group. Lader pulse was focused at corneal epithelium and an average of 25-30 applications were required to make the single pair of transverse line like conventional lineal corneal transverse incision for one eye. Changes ir keratometry and pachymetry were measured postlaser application for 3 months. Seven days after radiation, two rabbit eyes(2.5mJ and 5mJ) were enucleated for scanning electron microscopy. The results were as follows: 1. The mean flattening induced at 900 meridian was 1.91 diopter in 2.5mJ group and 1.98 diopter in 5mJ group 3 months after laser radiation, and the difference between the two groups was not statistically significant(p>0.5). 2. The steepening at 1800 meridian induced only one week after laser radiation in both groups, thereafter the flattening was shown. 3. The significant mean corneal thickness increase of 30.72pm in 2.5mJ group and 33.47 micrometer in 5mJ group was noted at postlaser 7 days and returned to normal range at postlaser 2 months, but the corneal thickness showed no significant statistical difference between two group(p>0.5). 4. Scanning electron microscopy findings showed changes of the ultrastructure of the endothelial cell: edematous changes of the endothelial cell and cell membrane destruction were much less in 2.5mJ group than 5mJ group.
Astigmatism
;
Cell Membrane
;
Cornea
;
Endothelial Cells
;
Endothelium*
;
Epithelium, Corneal
;
Microscopy, Electron, Scanning
;
Rabbits*
;
Reference Values
4.Nd:YAG Laser Effect on Corneal Curvature, Thickness and Endothelium in Rabbits.
Hak Seung KIM ; Yoon Won MYONG ; Sang Wook RHEE
Journal of the Korean Ophthalmological Society 1990;31(6):703-709
In order to evaluate the clinical application of the Nd:YAG laser(Coherent model 9900(R)) to correct the astigmatism, we observed the change in corneal curvature, thickness and endothelium after laser radiation to the rabbit cornea. The experiment composed of 14 rabbit eyes divided into two groups according to the power setting; 7 eyes of 2.5mJ group, and 7 eyes of 5mJ group. Lader pulse was focused at corneal epithelium and an average of 25-30 applications were required to make the single pair of transverse line like conventional lineal corneal transverse incision for one eye. Changes ir keratometry and pachymetry were measured postlaser application for 3 months. Seven days after radiation, two rabbit eyes(2.5mJ and 5mJ) were enucleated for scanning electron microscopy. The results were as follows: 1. The mean flattening induced at 900 meridian was 1.91 diopter in 2.5mJ group and 1.98 diopter in 5mJ group 3 months after laser radiation, and the difference between the two groups was not statistically significant(p>0.5). 2. The steepening at 1800 meridian induced only one week after laser radiation in both groups, thereafter the flattening was shown. 3. The significant mean corneal thickness increase of 30.72pm in 2.5mJ group and 33.47 micrometer in 5mJ group was noted at postlaser 7 days and returned to normal range at postlaser 2 months, but the corneal thickness showed no significant statistical difference between two group(p>0.5). 4. Scanning electron microscopy findings showed changes of the ultrastructure of the endothelial cell: edematous changes of the endothelial cell and cell membrane destruction were much less in 2.5mJ group than 5mJ group.
Astigmatism
;
Cell Membrane
;
Cornea
;
Endothelial Cells
;
Endothelium*
;
Epithelium, Corneal
;
Microscopy, Electron, Scanning
;
Rabbits*
;
Reference Values
5.A Case of Spontaneous Regression of Schnyder's Crystalline Corneal Dystrophy.
Chun Suk JUNG ; Yoon Won MYONG
Journal of the Korean Ophthalmological Society 2000;41(6):1441-1444
Schnyder's crystalline corneal dystrophy is a hereditary disease of unknown etiology and characterized by bilateral subepithelial corneal opacity with diffuse crystalline deposits of cholesterol or other lipid. The authors experienced a case of Schnyder's crystalline corneal dystrophy whose corneal opacity of left eye regressed gradually without treatment. This 40-year-old man had undergone keratoplasty on the right eye and adiagnosis of Schnyder's crystalline corneal dystrophy was made histopatho-logically. In this report, the authors describe a case of regression of Schnyder's crystalline corneal dystrophy without treatment.
Adult
;
Cholesterol
;
Corneal Opacity
;
Corneal Transplantation
;
Crystallins*
;
Genetic Diseases, Inborn
;
Humans
6.A Case of Posterior Polymorphous Dystrophy.
In Chul PARK ; Sung Kun CHUNG ; Yoon Won MYONG ; Sang Wook RHEE
Journal of the Korean Ophthalmological Society 1991;32(11):1020-1023
Posterior polymorphous dystrophy is a bilateral, dominantly inherited (rarely recessively inherited) disorder of corneal endothelium, characterized by a spectrum of changes in posterior cornea and less commonly in the iris and angle structures. We have experienced a 39-year-old male patient complaining of visual disturbance in the right eye. On examination, we found characteristics of postenor polymorphous dystrophy which were Descemet's membrane thickening. peripheral anterior synechiae, iridocorneal adhesion. abnormal corneal endothelial cells in both eyes, and corneal epithelial and stromal edema in the right eye and after penetrating keratoplasty, the result was good. Therefore, we report a case of posterior polymorphous dystrophy with review of literatures.
Adult
;
Cornea
;
Descemet Membrane
;
Edema
;
Endothelial Cells
;
Endothelium, Corneal
;
Humans
;
Iris
;
Keratoplasty, Penetrating
;
Male
7.A Clinical Evaluation of Ocular Manifestation in Bone Marrow Transplanted Patients.
Kyu Hong PAK ; Yoon Won MYONG ; Sang Wook RHEE
Journal of the Korean Ophthalmological Society 1991;32(4):294-299
During the last decade, allogeneic bone marrow transplantation(BMT) has become the treatment of choice in severe aplastic anemia and many types of leukemia. However, there are several complications such as Graft-vs-Host Disease(GVHD), infection, Host-vs-Graft Reaction(HVGR). One of the most serious late complications of BMT is GVHD. This immunological reaction is reportedly caused by donor T lymphocytes reacting against incompatible minor transplantation antigens in host tissue. The clinical manifestation of GVHD involves the skin, gastrointestinal tract, liver and mucosal membranes in the mouth and eyes. One of the most frequent ocular complication after BMT is the "dry eye syndrome" which involves conjunctiva, cornea and the lacrimal glands. The "dry eye" is characterized by subjective symptoms such as pain, foreign body sensation and decreased vision. The epithelial degeneration, due to reduced tear production and alteration in the tear film, creates dry spots and increased mucus strands and debris. We present an analysis of ocular manifestation of 27 out of 81 bone marrow transplanted patients for hematologic malignancies(HM) and severe aplastic anemia(SAA) from March 1983 to January, 1990 at St. Mary's Hospital. The results were as follows: 1) 16 out of 27(59%) BMT patients developed GVHD and 14 out of 27(52%) BMT patients developed dry eyes; 2) 11 out of 16(68%) patients with GVHD developed dry eyes; whereas, 3 out of 11(27%) patients without GVHD developed dry eyes(P<0.05); 3) Four out of 10(40%) patients with a GVHD developed dry eys, whereas 7 out of 11(64%) patients with cGVHD developed dry eyes.
Anemia, Aplastic
;
Bone Marrow*
;
Conjunctiva
;
Cornea
;
Dry Eye Syndromes
;
Foreign Bodies
;
Gastrointestinal Tract
;
Histocompatibility Antigens
;
Humans
;
Lacrimal Apparatus
;
Leukemia
;
Liver
;
Membranes
;
Mouth
;
Mucus
;
Sensation
;
Skin
;
T-Lymphocytes
;
Tears
;
Tissue Donors
8.The Effect of Indomethacin Pretreatment Before Nd:YAG Laser Anterior Capsulotomy on Intraoular Pressure of Rabbits.
Yoon Won MYONG ; Nam Ho BAEK ; Sang Wook RHEE
Journal of the Korean Ophthalmological Society 1993;34(5):408-417
To evaluate the cause of intraocular pressure elevation and the effect of indomethacin after Nd:YAG laser anterior capsulotomy in rabbit authors measured the intraocular pressure, prostaglandin E2 and thromboxane B2 concentrations of aquous humor, and observed the morphological change of trabecular meshwork using scanning electron microscope in indomethacin pretreatment (group I) and non-treatment (group II) group. The intraocular pressure and the concentrations of prostaglanding E2 and thromboxane B2 in group II were higher than in group I. And the scanning electron microscopy showed inflammatory reaction in group II. These results support that the causes of intraocular pressure elevation are elevation of prostaglandin E2. thromboxane B2 concentrations in aqueous humor and intraocular inflammation secondary to it.
Aqueous Humor
;
Dinoprostone
;
Indomethacin*
;
Inflammation
;
Intraocular Pressure
;
Microscopy, Electron, Scanning
;
Rabbits*
;
Thromboxane B2
;
Trabecular Meshwork
9.The Effect of Indomethacin Pretreatment Before Nd:YAG Laser Anterior Capsulotomy on Intraoular Pressure of Rabbits.
Yoon Won MYONG ; Nam Ho BAEK ; Sang Wook RHEE
Journal of the Korean Ophthalmological Society 1993;34(5):408-417
To evaluate the cause of intraocular pressure elevation and the effect of indomethacin after Nd:YAG laser anterior capsulotomy in rabbit authors measured the intraocular pressure, prostaglandin E2 and thromboxane B2 concentrations of aquous humor, and observed the morphological change of trabecular meshwork using scanning electron microscope in indomethacin pretreatment (group I) and non-treatment (group II) group. The intraocular pressure and the concentrations of prostaglanding E2 and thromboxane B2 in group II were higher than in group I. And the scanning electron microscopy showed inflammatory reaction in group II. These results support that the causes of intraocular pressure elevation are elevation of prostaglandin E2. thromboxane B2 concentrations in aqueous humor and intraocular inflammation secondary to it.
Aqueous Humor
;
Dinoprostone
;
Indomethacin*
;
Inflammation
;
Intraocular Pressure
;
Microscopy, Electron, Scanning
;
Rabbits*
;
Thromboxane B2
;
Trabecular Meshwork
10.Difference of Corneal Thickness in Enucleated Eye.
Seong Hwan KIM ; Sung Kun CHUNG ; Yoon Won MYONG
Journal of the Korean Ophthalmological Society 1998;39(7):1334-1339
The maintenance of corneal endothelial cells is essential for success of corneal transplantation. Endothelial cell count by specular microscope and measurement of donor corneal thickness is useful in measuring the function of cornea. We studied difference of corneal thickness in central and peripheral corneal region in enucleated eye. We measured corneal thickness of 48 eyes(48 persons) with ultrasound pachymetry that were presented to The Eye Bank of Catholic University Medical College. Average age was 61.42+/-16.12 years and average time was 163.02+/-102.52 minutes until measurement of corneal thickness after death. Increased amount of corneal thickness was 136.73+/-101.44micrometer in center and 61.37+/135.46micrometer in periphery compared with normal average corneal thickness. According to these results, corneal edema due to functional loss of endothelial cells after death lead to increased corneal thickness, especially in central region being more statistically significant than peripheral region (p=0.002).
Cornea
;
Corneal Edema
;
Corneal Transplantation
;
Endothelial Cells
;
Eye Banks
;
Humans
;
Tissue Donors
;
Ultrasonography