Relationship between Ocular Fatigue and Use of a Virtual Reality Device

PURPOSE: To investigate ocular fatigue after the use of a head-mounted display (HMD)-type virtual reality device.METHODS: Healthy adult volunteers were examined for ocular fatigue before and after watching videos for 10 min with an HMD-type virtual reality device. Subjective ocular fatigue was measured using a questionnaire. Objective fatigue was measured using the critical flicker fusion frequency (CFF), high frequency component of accommodative microfluctuation, and accommodation amplitude. The accommodation amplitude was measured using the push-up method and the dynamic measurement mode of the autorefractometer. Changes in the spherical equivalent were also measured.RESULTS: The questionnaire-based subjective ocular fatigue increased (p = 0.020) after use of the HMD device. In the dominant eye, the high frequency component of accommodative microfluctuation increased (p < 0.05). The accommodation amplitude using the push-up method was decreased in the nondominant eye (p = 0.007), and temporary myopia was observed (p < 0.05). However, there was no increase in ocular fatigue in the CFF or the accommodation amplitude using the dynamic measurement mode, which showed no significant difference before and after using the HMD device (p > 0.05).CONCLUSIONS: A subjective test and some objective tests suggested that use of the HMD-type virtual reality display increased ocular fatigue. However, no increase in ocular fatigue was measured using CFF nor in the accommodation amplitude using the dynamic measurement mode which was a limitation of the study. More studies with the aim to alleviate ocular fatigue after using HMD-type virtual reality devices are therefore needed.

Osteoma Cutis on Eyelid

PURPOSE@#To present the first report describing lesions of osteoma cutis on the upper eyelid and medial canthus.CASE SUMMARY: A 4-year-old female complained of a right upper eyelid mass. The examination showed a well-delineated, mild bluish-colored, hard mass over the upper eyelid and the medial canthus measuring 10 × 10 mm and 2 × 2 mm. During the cutaneous examination, her forearm, left shin, right dorsum of the foot, neck, and abdominal wall also showed well-delineated, mild bluish-colored, immobile hard masses, similar to the upper eyelid mass. A right upper eyelid and medial canthus mass excision was performed and a biopsy specimen was collected. Hematoxyline and eosin staining showed a mature bone in the dermis with spicules of bone and osteoblasts. She was finally diagnosed with osteoma cutis on the upper eyelid and the medial canthus.@*CONCLUSIONS@#Osteoma cutis is a rare, benign skin disorder characterized by bone formation in the skin. Albright hereditary osteodystrophy, which causes a metabolic disorder, should also be considered to prevent complications.

Comparison of physical properties of the various 3D printing temporary crown and bridge resin / 대한치과재료학회지

Conventional dental resins for crown and bridge fulfill ISO 10477 and ISO 10993 before clinical application. Although 3D printing or rapid prototyping (RP) for the fabrication of temporary crown and bridge have been proposed, a little studies were reported for 3D printing resin for temporary crown and bridge. The purpose of this study was to evaluate the physical properties (such as water sorption and solubility, color stability and flexural strength) of the various 3D printing temporary crown and bridge resin following the ISO 10477:2018 and estimate the effect of chemical composition of resin on the physical properties. Four resins approved by KFDA and 4 experimental resins developed by different manufacturer were tested in this study. Samples were prepared with DLP typed 3D Printer (G-Printer) and post-cured using UV-light Cure Unit (Cure M). Proper 3D printing and post-curing conditions were selected for different 3D printing resins. Each test was performed according to the ISO 10477 and results were statistically analyzed using Tukey-multiple comparison test (p=0.05). Only group-B did not satisfied the ISO requirement ( 60 MPa). Resin components may affect the flexural strength, then user should check the components of 3D printing resin. Deficient degree of polymerization may lead to large water sorption, water solubility and color changes. Further study should be done comparison between specimens printed with specific 3D printer recommended by manufacturer and specimens used in this study.

Effects of acid-treatment conditions on the surface properties of the RBM treated titanium implants / 대한치과재료학회지

The purpose of this study was to evaluate the effect of acid-treatment conditions on the surface properties of the RBM (Resorbable Blast Media) treated titanium. Disk typed cp-titanium specimens were prepared and RBM treatments was performed with calcium phosphate ceramic powder. Acid solution was mixed using HCl, H2SO4 and deionized water with 4 different volume fraction. The RBM treated titanium was acid treated with different acid solutions at 3 different temperatures and for 3 different periods. After acid-treatments, samples were cleaned with 1 % Solujet solution for 30 min and deionized water for 30 min using ultrasonic cleanser, then dried in the electrical oven (37℃). Weight of samples before and after acid-treatment were measured using electric balance. Surface roughness was estimated using a confocal laser scanning microscopy, crystal phase in the surface of sample was analyzed using X-ray diffractometer. Surface morphology and components were evaluated using Scanning Electron Microscope (SEM) with Energy Dispersive X-ray spectroscopy (EDX) and X-ray Photoemission Spectroscopy (XPS). Values of the weight changes and surface roughness were statistically analyzed using Tukey-multiple comparison test (p=0.05). Weight change after acid treatments were significantly increased with increasing the concentration of H₂SO₄ and temperature of acid-solution. Acid-treatment conditions (concentration of H₂SO₄, temperature and time) did not produce consistent effects on the surface roughness, it showed the scattered results. From XRD analysis, formation of titanium hydrides in the titanium surface were observed in all specimens treated with acid-solutions. From XPS analysis, thin titanium oxide layer in the acid-treated specimens could be evaluated. Acid solution with 90℃ showed the strong effect on the titanium surface, it should be treated with caution to avoid the over-etching process.

Heterotopic bone formation in normal gastric cardiac mucosa / 영남의대학술지

Heterotopic bone formation in the gastrointestinal tract is a rare phenomenon. Most reported cases were associated with benign and malignant neoplasms, except for a case in which heterotopic bone formation was found in a patient with Barrett's esophagus. The exact pathogenesis of the disease has not yet been established. However, most heterotopic bones found in the gastrointestinal tract were associated with mucinproducing tumors of the appendix, colon, and rectum. Inflammation may also play a role in osseous metaplasia in a case with bone formation at the base of an ulcer in Barrett's esophagus. Here, we report on a patient with heterotopic bone formation in normal gastric cardiac mucosa. A 50-year-old female visited our hospital for a routine health examination. She had no gastrointestinal symptoms, and her physical examination, blood test, X-ray, urine, and stool examination results were normal. A 0.3 cm sized polypoid lesion located just below the squamocolumnar junction was observed on upper gastrointestinal endoscopy. A piece of biopsy was taken. Histologically, a lamella bone trabecula and chronic inflammatory cells were observed in the gastric cardiac mucosa. The follow-up endoscopy performed one month later showed no residual lesion.

A comparative study on the fracture behavior of zironia, glass infiltrated alumina and PFM full crown system / 대한치과보철학회지

PURPOSE: The purpose of this study was to compare the fracture behavior of Zironia, glass infiltrated Alumina and PFM full crown system. MATERIALS AND METHODS: Fifteen crowns for each of 3 experimental groups (Zironia, glass infiltrated Alumina and PFM full crown) were made by the conventional method. The crowns mounted on the testing jig were inclined in 30 degrees to the long axis of the tooth and the universal testing machine was used to measure the fracture strength. RESULTS: 1. The mean fracture strengths were 588.3 +/- 49.6 MPa for zirconia system, 569.1 +/- 61.8 MPa for PFM system and 551.0 +/- 76.5 MPa for glass-infiltrated alumina system (P>.05). 2. The mean shear bond strengths were 25.5 +/- 5.6 MPa for zirconia system, 38.9 +/- 5.0 MPa for Ni-Cr alloy system and 39.4 +/- 5.1 MPa for glass-infiltrated alumina system. 3. The chemical bonding was observed at interfaces between PFM or glass-infiltrated alumina and veneering porcelain, however, no chemical bonding was observed at interface between zirconia and veneering porcelain. CONCLUSION: With the study, the fracture strengths of PFM crown system had a higher fracture strength than conventional zirconia system crown and glass-infiltrated alumina crowns. and than the shear bond strengths glass-infiltrated alumina system had a higher shear bond strength than conventional PFM system and zirconia system.

Colon Interposition after Radical Total Pharyngolaryngoesophagectomy in a Patient with Subtotal Gastrectomy

The principle treatment for cervical esophageal cancer and hypopharyngeal cancer with esophageal invasion is radical total pharyngolaryngoesophagectomy (PLE), and it is necessary to totally reconstruct the defect of the resected organ. Stomach, small bowel, colon, a laryngotracheal flap and a pectoralis major musculocutaneous flap can all be used. We commonly use stomach because stomach has a rich blood supply and a low incidence of leakage. But in this present reported case, because previous radical subtotal gastrectomy with gastrojejunostomy had been done, we had to use colon for reconstruction. We use the left colon and left colic artery, and there were no complications. We report here on using the left colon and left colic artery to reconstruct a PLE defect for the first time in Korea.

Congenital Microgastria: Treatment with a Hunt-Lawrence Pouch

Congenital microgastria results in growth retardation early in a patient's life due to poor oral intake, malnutrition and failure to gain weight. An one-month-old female was admitted with a history of poor oral intake, vomiting and recurrent pneumonia after birth. She had an extremely small, tubular stomach in the midline of the abdomen, a megaesophagus and severe gastroesophageal reflux (Reflux Index: 41.1%, DeMeester score: 152.2). A Hunt- Lawrence Pouch (Roux-en-Y double barrel jejunal food pouch formation) procedure was performed for augmenting the small stomach after failure of conservative management such as small, frequent feedings and prokinetics. The postoperative UGI and esophageal pH study showed marked improvement of the GER (13.7%, 68.9 respectively). Although her preoperative symptoms have subsided, her weight is still below normal (third percentile). Creating a Hunt-Lawrence pouch is the treatment of choice for congenital microgastria that is refractory to conservative management.

Correction of Superior Sulcus Deformity and Enophthalmos with Porous High-density Polyethylene Sheet in Anophthalmic Patients

PURPOSE: Superior sulcus deformity is the main cosmetic problem in anophthalmic patients. Many methods of correcting enophthalmos have been reported, especially in patients with orbital wall fracture. The purpose of this study is to review the long term results of effectiveness in superior sulcus deformity correction by subperiosteal Medpor (R) sheet implantation in anophthalmic patients. METHODS: Subperiosteal Medpor (R) sheets were used in 11 eyes of 11 anophthalmic patients. To estimate the effectiveness, photographs were taken and exophthalmometric value with their own prosthesis using Hertel exophthalmometer was measured in all patients before and after surgery. RESULTS: The overall cosmetic results in superior sulcus deformity were 'excellent' in 3 (27.3%), 'good' in 6 (54.5%), 'fair' in 2 (18.2%). The overall results in enophthalmos were 'excellent' in 3 (27.2%), 'markedly improved' in 4 (36.4%), 'slightly improved' in 4 (36.4%). Most patients had a marked increase in orbital volume, except two patients. They received irradiation treatment in early childhood so showed unsatisfactory results in both superior sulcus deformity and enophthalmos. CONCLUSIONS: Subperiosteal Medpor (R) sheet implantation is considered to be a reliable and safe procedure without serious complication and with an excellent cosmetic results.

Clinical Study of Circular Stapler Hemorrhoidectomy

PURPOSE: A circular stapler hemorrhoidectomy is widely used to treat hemorrhoids and has the advantages of less pain and an earlier return to work compared with a conventional excisional hemorrhoidectomy. This study examined the clinical significance and efficacy of a circular stapled hemorrhoidectomy. METHODS: One hundred eighty-six (186) patients with prolapsed hemorrhoids underwent surgery using a circular stapler. The patients' characteristics, the operation time, the postoperative course, the procedure- related factors, the pain, and the complications were analyzed. All the patients received a follow-up examination at the outpatient clinic, including the time to return to work, and the degree of satisfaction was analyzed. RESULTS: Grade-III hemorrhoids were the most common complaint (74.1%), followed by grade-IV hemorrhoids (23.7%). Twenty-one cases (11.3%) had undergone previous anal operations: hemorrhoids, fissure, and fistula. Regarding the anesthetic method, caudal anesthesia was used in 59.7% of the cases, and spinal or saddle anesthesia was used in 39.2%. The mean operation time was 19.1 minutes (range: 8~50). The postoperative pain scores were 3.4 on the operation day, 2.1 on the postoperative 3rd day, and 0.9 on the postoperative 7th day. During the operation, a hemostatic suture was made at the suture line in 72.0% of the cases. Muscle involvement was detected at a donut specimen grossly in 9% of cases and microscopically in 48.9%. The mean thickness of muscle involvement was 2.5 mm. In the postoperative course, the time for the first bowel movement was 1.2 days, and the mean hospital stay was 2.1 days. The mean time needed for the patient to return to work was 6.2 days. The most common complication encountered was urinary problems (34.9%). The incidence of postoperative bleeding was 2.2%. Postoperative follow- up revealed one case of a hemorrhoids recurrence and one case of temporary fecal incontinence. CONCLUSIONS: The circular stapler hemorrhoidectomy has no disadvantage in terms of operation time and operative course, and has an advantage in terms of operative pain and an earlier return to normal work without any significant or serious complications. Moreover, it has minimal long-term complications. Therefore, a circular stapler hemorrhoidectomy can be performed safely and is recommended as a useful method for treating hemorrhoids.

Three Cases of Orbitofrontal Cholesterol Granuloma

PURPOSE: To report three cases of orbitofrontal cholesterol granuloma. METHODS: The study subjects were three patients with chief complaints of proptosis and upgaze limitation of ocular movement. Exophthalmometric values were 4~8 mm by Hertel exophthalmometer. Orbital CT and MRI scans were taken in all patients, and regarded as orbitofrontal cholesterol granuloma. In all cases, excisional biopsy was done through the lateral approach. RESULTS: Orbital CT scan showed an isodense to hypodense, well-defined, homogeneous mass and osteolytic lesion in the adjacent superolateral bony orbit. Orbital MRI scan showed a mass with high signal intensity in both T1- and T2-weighted images. Histopathologically, the specimen showed numerous slits like cholesterol clefts surrounded by multinucleated, foreign body type, giant cells with hemosiderin pigments. CONCLUSIONS: Orbitofrontal cholesterol granuloma, although rare, has typical clinical and radiologic features. Surgical excision has a high success rate without recurrence.

Fibrovascularization of Intraorbital Hydroxyapatite-Coated Alumina Sphere in Rabbits

We investigated the fibrovascular ingrowth and fibrovascular tissue maturation of hydroxyapatite-coated, porous alumina sphere (Alumina sphere) in comparison with the hydroxyapatite sphere (HAp sphere) in rabbits. Alumina spheres and HAp spheres were implanted in the left orbits of 42 New Zealand white rabbits after enucleation. Fibrovascular ingrowth and maturation were graded from 1 to 5 at postoperative 1, 2, 3, 4, 8, 12 and 24 weeks. We defined 4 phases: postoperative 1-2 weeks as phase I, 3-4 weeks as phase II, 8-12 weeks as phase III, and 24 weeks as phase IV. The grade was analyzed at each phases. There was no significant difference in fibrovascular ingrowth and maturation between the two groups at all 4 phases, except phase II at which the Alumina sphere showed significantly lower maturation grade (p< 0.05). We concluded that the Alumina sphere is an ideal orbital implant material and an ideal substitute for the HAp sphere in clinical practice.

Evaluation and Treatment of True Ptosis in Double Elevator Palsy

PURPOSE: To estimate the predictable factors of postoperative true ptosis remaining after squint surgery in patients with double elevator palsy (DEP), and to analyze the factors that must be considered before the correction of true ptosis. METHODS: We retrospectively reviewed the medical records of 6 patients who had undergone strabismus surgery for DEP at the Department of Ophthalmology, Yeungnam University College of Medicine, between 1989 and 2003. The MRD (margin reflex distance) of paretic and nonparetic eye with each eye fixation, palpebral aperture, levator function, and Bell's phenomenon were analyzed before and after squint surgery. RESULTS: True ptosis was noted in 3 patients, one of whom underwent external levator resection. Postoperative Bell's phenomenon improved in 2 patients who had poor Bell's phenomenon preoperatively. Scleral show remained in 2 patients who underwent inferior rectus recession, and was taken into account before the correction of ptosis. CONCLUSIONS: Upper lid drooping in DEP patients is expected to be improved after squint surgery if preoperative MRD of paretic eye with paretic eye fixation has the same measured amount as that of non-paretic eye. MRD, Bell's phenomenon and the amount of scleral show after the squint surgery should be carefully examined and assessed before the correction of residual ptosis.

Surgical Effect of Canaliculodacryocystorhinostomy in Patients with Failed Conjunctivodacryocystorhinostomy

PURPOSE: To analyze outcomes of the canaliculodacryocystorhinostomy and the combined procedure of canaliculodacryocystorhinostomy and Jones tube reinsertion, in patients who had complications of conjunctivodacryocystorhinostomy, which required other surgical procedures. METHODS: We retrospectively analyzed the outcomes of 18 eyes (16 patients) who visited the Department of Ophthalmology, Yeungnam University Hospital for functional failures and complications of conjunctivodacryocystorhinostomy, and who underwent either the canaliculodacryocystorhinostomy or the combined procedure between February 1994 and October 2003. These patients had submerged, prolapsed, lost, or obstructed Jones tubes, with a length of patent canaliculi from the puncta of more than 7mm, identified with probing, irrigation and dacryocystography. RESULTS: Complete or significant improvement of epiphora was achieved in 83.3% (15 of 18 eyes) after a follow-up period ranging 6 to 70 months (average 28.5 months). CONCLUSIONS: Canaliculodacryocystorhinostomy and the combined procedure can be expected to achieve functional success in patients who suffer from complications of the Jones tube. We recommend these procedures in cases of common canalicular obstruction and upper and lower canalicular obstruction with a length of patency greater than 7mm.

The Clinical Significance of Oral Glucose Tolerance Test in Gestational Diabetes Mellitus / 대한산부인과학회잡지

OBJECTIVE: This study was performed to identify the clinical characteristics on the prevalence of gestational diabetes mellitus (GDM) related to risk factors and to assess the significance of screening test. METHODS: From Jan. 2000 to Dec. 2001, 513 women attending prenatal clinic were screened for GDM. Universal screening with 50 gm GTT were performed during 24-28th gestational weeks period. Women with 1 hour plasma glucose >or=140 mg/dl underwent 100 gm GTT for diagnosis of GDM. The patients were divided into high risk and control group. RESULTS: The overall incidence of GDM was 3.1%. Among high risk group and control group, the prevalence of positive screening tests were 28.9% vs 13.6% (P=0.001), and frequencies of abnormal 100 gm GTTs were 8.8% vs 0.6% (P=0.001), respectively. These rates were statistically significant. The significant risk factors were glucosuria, family history of DM and obesity (BMI >or=25). With increasing BMI, the prevalence of GDM was found to be significantly increased. CONCLUSION: The screening test of GDM would be preferable for all pregnant women rather than risk group only. Intensified management approach is needed for patients with glucosuria, family history of DM or obesity.

The Obstetrical and Statistical Aspects of the Unmarried mother / 대한산부인과학회잡지

OBJECTIVE: We focused the objective of this study on the obstetrical and statistical aspects of the unmarried mother, especially teenage pregnancy and 20's pregnancy. METHODS: The 112 well-documented records in the 130 unmarried mothers who delivered at Gangnam general hospital public corporation from 1998 to 2000, were enrolled in our study. Unmarried mothers were divided into three age groups; teenage group, 20's group and 30's group, then, each group was analyzed by liable methods, SPSS (Version 10.0.7) and data were processed by Student's t-test and accepted as the significant meaning within p-value less than 0.05, 95% significant level. RESULTS: In this study, teenage mothers were delivered lower birth weight babies than those of other groups (p=0.000001). Sex partners of teenage mothers, most school boy friends, were similar age to those mothers and low economic state. Despite desire of bringing up children (teenage 11% versus 20's 36%), they gave up their babies because of monetary matters and social bias. And teenage mothers felt stronger affection for babies than 20's. Teenagers' and 20's unmarried mothers have poor information about contraception (teenage group 42%, 20's 31%). CONCLUSION: The unmarried mothers have been constituting many social problems. Fortunately, the absolute number of the unmarried mothers have not increased but the teenage pregnancy has the majority of unmarried mothers (> OR =50%). It is necessary for unmarried mothers to take the education of contraceptive measures, the social systems of bringing up the boarder babies and the retraining courses of unmarried mothers.

The Obstetrical and Statistical Aspects of the Unmarried mother / 대한산부인과학회잡지

OBJECTIVE: We focused the objective of this study on the obstetrical and statistical aspects of the unmarried mother, especially teenage pregnancy and 20's pregnancy. METHODS: The 112 well-documented records in the 130 unmarried mothers who delivered at Gangnam general hospital public corporation from 1998 to 2000, were enrolled in our study. Unmarried mothers were divided into three age groups; teenage group, 20's group and 30's group, then, each group was analyzed by liable methods, SPSS (Version 10.0.7) and data were processed by Student's t-test and accepted as the significant meaning within p-value less than 0.05, 95% significant level. RESULTS: In this study, teenage mothers were delivered lower birth weight babies than those of other groups (p=0.000001). Sex partners of teenage mothers, most school boy friends, were similar age to those mothers and low economic state. Despite desire of bringing up children (teenage 11% versus 20's 36%), they gave up their babies because of monetary matters and social bias. And teenage mothers felt stronger affection for babies than 20's. Teenagers' and 20's unmarried mothers have poor information about contraception (teenage group 42%, 20's 31%). CONCLUSION: The unmarried mothers have been constituting many social problems. Fortunately, the absolute number of the unmarried mothers have not increased but the teenage pregnancy has the majority of unmarried mothers (> OR =50%). It is necessary for unmarried mothers to take the education of contraceptive measures, the social systems of bringing up the boarder babies and the retraining courses of unmarried mothers.

Long Term Surgical Efficacy of Endonasal Dacryo cys torhinostomy

Primary success rate of endonasal dacryocystorhinostomy has been reported lower than that of conventional cedure. Gradual stenosis of mucosal ostium would progress until 6 to 10 months following operation and a longterm follow-up should be necessary. Endonasal dacryocystorhinostomy was performed in 100 patients[118 eyes]between July 1993 and March 1998 at the Department of Ophthalmology, Yeungnam University College of Medicine. After the follow-up period of 1 to 4 years[average 16.2 months], longterm success rate, postoperative omplications, and factors to affect success rate were studied. The success rate of primary operation was 89.83%, and the success rate after secondary revision of the ostium was up to 99.15%. Granulation tissue formation was the most common postoperative complication, and other complications included protrusion of silicone tube, membranous obstruction, partial obstruction of common canaliculus, canaliculitis and prolapse of orbital fat. Factors to obtain good success rate were careful and acurate surgical technique to achieve large mucosal ostium, postoperative management, antibiotics and steroid medication, etc. Long-term surgical efficacy of endonasal dacryocystorhinostomy was similar to skin approach and secondary success rate following revision was very satisfactory.

The Effect of Posterior Vitreous Detachment on Visual Prognosis in Branch Retinal Vein Occlusion

The common causes of visual loss in branch retinal vein occlusion[BRVO] have been reported as the macular edema, macular non-perfusion and the vitreous hemorrhage due to neovascularization.These factors have close relationship with the status of the posterior vitreous. The purpose of this study was to evaluate the factors of visual prognosis in BRVO and the relationship between visual prognosis and vitreomacular status.Fifty-two patients with branch retinal vein occlusion in the department of ophthalmology, Yeungnam University college of Medicine were included for vitreo macular examination.The eyes were classified as two groups, vitreomacular attachment[Group I]and posterior vitreous detachment[Group II]. The incidence of macular edema was significantly lower in eyes with group I [Fisher's exact Test:p<0.05].Final visual acuity was better than the initial visual acuity, regardless of the presence of posterior vitreous detachment [Paired t-test:p<0.01].Group I developed higher rate of neovascularization and vitreous hemorrhage, but statistical significance was not noted.