Forecasting of the COVID-19 pandemic situation of Korea

For the novel coronavirus disease 2019 (COVID-19), predictive modeling, in the literature, uses broadly susceptible exposed infected recoverd (SEIR)/SIR, agent-based, curve-fitting models. Governments and legislative bodies rely on insights from prediction models to suggest new policies and to assess the effectiveness of enforced policies. Therefore, access to accurate outbreak prediction models is essential to obtain insights into the likely spread and consequences of infectious diseases. The objective of this study is to predict the future COVID-19 situation of Korea. Here, we employed 5 models for this analysis; SEIR, local linear regression (LLR), negative binomial (NB) regression, segment Poisson, deep-learning based long short-term memory models (LSTM) and tree based gradient boosting machine (GBM). After prediction, model performance comparison was evelauated using relative mean squared errors (RMSE) for two sets of train (January 20, 2020‒December 31, 2020 and January 20, 2020‒January 31, 2021) and testing data (January 1, 2021‒February 28, 2021 and February 1, 2021‒February 28, 2021) . Except for segmented Poisson model, the other models predicted a decline in the daily confirmed cases in the country for the coming future. RMSE values’ comparison showed that LLR, GBM, SEIR, NB, and LSTM respectively, performed well in the forecasting of the pandemic situation of the country. A good understanding of the epidemic dynamics would greatly enhance the control and prevention of COVID-19 and other infectious diseases. Therefore, with increasing daily confirmed cases since this year, these results could help in the pandemic response by informing decisions about planning, resource allocation, and decision concerning social distancing policies.

Forecasting of the COVID-19 pandemic situation of Korea

For the novel coronavirus disease 2019 (COVID-19), predictive modeling, in the literature, uses broadly susceptible exposed infected recoverd (SEIR)/SIR, agent-based, curve-fitting models. Governments and legislative bodies rely on insights from prediction models to suggest new policies and to assess the effectiveness of enforced policies. Therefore, access to accurate outbreak prediction models is essential to obtain insights into the likely spread and consequences of infectious diseases. The objective of this study is to predict the future COVID-19 situation of Korea. Here, we employed 5 models for this analysis; SEIR, local linear regression (LLR), negative binomial (NB) regression, segment Poisson, deep-learning based long short-term memory models (LSTM) and tree based gradient boosting machine (GBM). After prediction, model performance comparison was evelauated using relative mean squared errors (RMSE) for two sets of train (January 20, 2020‒December 31, 2020 and January 20, 2020‒January 31, 2021) and testing data (January 1, 2021‒February 28, 2021 and February 1, 2021‒February 28, 2021) . Except for segmented Poisson model, the other models predicted a decline in the daily confirmed cases in the country for the coming future. RMSE values’ comparison showed that LLR, GBM, SEIR, NB, and LSTM respectively, performed well in the forecasting of the pandemic situation of the country. A good understanding of the epidemic dynamics would greatly enhance the control and prevention of COVID-19 and other infectious diseases. Therefore, with increasing daily confirmed cases since this year, these results could help in the pandemic response by informing decisions about planning, resource allocation, and decision concerning social distancing policies.

Clinical Analysis Comparing Efficacy between a Distal Filter Protection Device and Proximal Balloon Occlusion Device during Carotid Artery Stenting

OBJECTIVE: The main concern during transfemoral carotid artery stenting (CAS) is preventing cerebral embolus dislodgement. We compared clinical outcomes and intraprocedural embolization rates of CAS using a distal filter protection device or proximal balloon occlusion device. METHODS: From January 2011 to March 2015, a series of 58 patients with symptomatic or asymptomatic internal carotid artery stenosis > or =70% were treated with CAS with embolic protection device in single center. All patients underwent post-CAS diffusion-weighted magnetic resonance imaging (DW-MRI) to detect new ischemic lesions. We compared clinical outcomes and postprocedural embolization rates. RESULTS: CAS was performed in all 61 patients. Distal filter protection success rate was 96.6% (28/29), whose mean age was 70.9 years, and mean stenosis was 81%. Their preprocedural infarction rate was 39% (11/28). Subsequent DW-MRI revealed 96 new ischemic lesions in 71% (20/28) patients. In contrast, the proximal balloon occlusion device success rate was 93.8% (30/32), whose mean age was 68.8 years and mean stenosis was 86%. Preprocedure infarction rate was 47% (14/30). DW-MRI revealed 45 new ischemic lesions in 57% (17/30) patients. Compared with distal filter protection device, proximal balloon occlusion device resulted in fewer ischemic lesions per patient (p=0.028). In each group, type of stent during CAS had no significant effect on number of periprocedural embolisms. Only 2 neurologic events occurred in the successfully treated patients (one from each group). CONCLUSION: Transfemoral CAS with proximal balloon occlusion device achieves good results. Compared with distal filter protection, proximal balloon occlusion might be more effective in reducing cerebral embolism during CAS.

Spontaneous Spinal Subdural Hematoma causing Brown-Sequard Syndrome with Thrombocytopenic Myelodysplastic Syndrome

Spontaneous spinal subdural hematoma (SSDH) is a very rare condition. We report a case of SSDH presenting with Brown-Sequard syndrome, treated by surgical evacuation. A 77-year-old woman was hospitalized for back pain without trauma history. As she showed progressive sensory loss and right-side dominant paraparesis, we performed magnetic resonance imaging and confirmed the SSDH in the thoracic area. Therefore, she underwent emergent operation and the hematoma was evacuated successfully. After the operation, the patient showed improvement in neurologic function.

A Case of Plexiform Neurofibroma with Severe Ptosis and Proptosis

PURPOSE: We present a case of plexiform neurofibroma that extensively invaded cranial and temporal bone, eyelid, orbit and uveal tissues, showing signs of severe ptosis and proptosis and symptoms of headache and ocular pain. METHODS: A 24-year old woman visited our clinic with pain and progressive proptosis, which had persisted for 2 weeks. She had a history of congenital neurofibromatosis. There were multiple Cafe-au-lait spots on her extremities, trunk, and face. Also, she had severe ptosis in her upper left eyelid, proptosis, and a distorted and asymmetric facial form. The cornea was markedly edematous. An enhanced computed tomography scan revealed an uncertain circumscribed soft tissue mass with enlargement of the eyeball and orbit, coupled with sphenoid wing dysplasia and herniation of the dura mater into the orbit due to expansion and bony destruction of the superior orbital wall. Under general anesthesia, the patient underwent excision and histopathologic biopsy of intraocular neurofibroma through evisceration. RESULTS: The tumor had black-colored multilobular nodules whose dimensions were 1.5x1.2x0.4 cm. After a histopathologic examination, the tumor was determined to be a pigmentary hamartoma of the uvea. Based on the clinical and histologic findings, we diagnosed the patient with plexiform neurofibroma with type I neurofibromatosis.

A Case of Atypical Miller Fisher Sndrome

PURPOSE: To report one case of atypical Miller Fisher syndrome with spontaneous recovery. METHODS: A 44-year-old woman was visited our clinic complaining of diplopia for 2 days. She has irregular medication history for thyroid dysfunction, and there was no antecedent respiratory or gastrointestinal infection. The best corrected visual acuity of both eyes was 20/20. She showed bilateral proptosis and limitation of abduction and supraduction, mild blepharoptosis of left eye and esotropia of 30 prism diopter (PD). RESULTS: Thyroid fuction test, orbital CT and electromyography were normal. Cerebrospinal fluid (CSF) analysis revealed albuminocytologic dissociation. Steroid pulse therapy was started promptly, but there was no improvement. Extraocular movement and diplopia gradually improved after 4 weeks of onset. and spontaneously recovered completely after 2 months. CONCLUSIONS: We reported a case of atypical Miller Fisher syndrome that completely and spontaneously recovered within 2 months., and represented normal findings by every examination such as orbital CT, thyroid function test, electromyography and CSF analysis.

Reconstruction of Orbital Wall Fracture with Resorbable Copolymer Mesh

PURPOSE: BioSorbFX(R)(BIONX Implant Inc.) and Macropore(R)(Medtronics Inc.) are mesh-type resorbable copolymer plate. This report presents a new model necessary for orbital wall reconstruction, accoding to the operative outcomes of orbital fracture with its use. METHODS: A follow-up on 11 patients was performed to ascertain the operative effects of the mesh-type resorbable material for 6 months. RESULTS: The patients were 7 males and 4 females. The patients' average age was 29.7 years and the mean follow-up period was 8.1 months. The most common site of fracture was inferior wall. In these cases, simultaneous fracture of the medial wall and floor was frequently observed. One case showed limitation of ocular movement, diplopias and enophthalmos simultaneously; 3 cases, enophthalmos and diplopia; 5 cases showed limitation of ocular movement and diplopia; and 2 cases, considerable possibility or the presence of enophthalmos due to extended fracture size. The cases improved remarkably after being operated and none were observed to have worsened. Moreover, serious complications, such as visual loss, the infection of implants, dislocation, exposure, etc., were not observed. CONCLUSIONS: Altogether, it is considered that the mesh-type resorbable copolymer plate may be safely used in orbital wall reconstruction without conspicuous complication.

A Silastic Sheet found during Endoscopic Transnasal Dacryocystorhinostomy for Acute Dacryocystitis

PURPOSE: To report the case of a silastic sheet that was found during an endoscopic transnasal dacryocystorhinostomy for treatment of acute dacryocystitis with necrosis of the lacrimal sac. METHODS: A thirty-two year old male presented with painful swelling on the nasal side of his left lower lid two weeks prior to visiting this clinic. Fourteen years ago, the patient was involved in a traffic accident and underwent surgery to reconstruct the ethmoidal sinus. Lacrimal sac massage showed a regurgitation of a purulent discharge from the left lower punctum. Therefore, the patient was diagnosed with acute dacryocystitis and an endoscopic transnasal dacryocystostomy was performed the next day. RESULTS: The surgical finding showed severe necrosis around the lacrimal sac and a 20 x 15-mm sized silastic sheet was found crumpled within the purulent discharge. The sheet was removed, the lacrimal sac was irrigated with an antibiotic solution, and a silicone tube was intubated into the lacrimal pathway. After surgery, the painful swelling on the nasal side of left lower lid resolved gradually, and there were no symptomatic complications three months later. CONCLUSIONS: We report the first case where a silastic sheet applied during a facial reconstruction had migrated adjacent to the lacrimal sac resulting in severe inflammation.

A Case of Alveolar Rhabdomyosarcoma of the Ethmoid Sinus Invading the Orbit in an Adult

PURPOSE: A case study and literature review of alveolar rhabdomyosarcoma (RMS) in an adult. METHODS: A 48-year-old male patient presented at our clinic complaining of proptosis that had persisted for 2 weeks in his left eye. A computed tomography (CT) scan revealed a destructive soft-tissue mass in the left ethmoid sinus with invasion of the left orbit and compression of the medial rectus muscle. Endoscopic intranasal biopsy revealed alveolar RMS. Conservative debulking and orbital wall decompression were performed. RESULTS: Immunohistochemical testing was positive for desmin, S-100, and smooth muscle actin (SMA), supporting the diagnosis of RMS. Since ipsilateral cervical and spinal metastasis was detected, systemic treatment was administered simultaneously. CONCLUSIONS: Although rarely found in adults, RMS should be considered in the differential diagnosis of orbital tumors. Immunohistochemical analysis plays an important role in the definitive diagnosis of RMS.

A Case of Leiomyosarcoma of the Conjunctiva

PURPOSE: We describe a very rare the leiomyosarcoma that developed in the conjunctiva. METHODS: A 59-year-old man was treated at another hospital two months before presenting to our institution. He had not gotten any better and so was admitted to our hospital. He had normal visual acuity and intraocular pressure. However, we found a geographic, highly vascularized mass involving the corneal limbus in the medial bulbar conjunctiva, from which a pterygium had been removed a year previously. An excision of the mass was carried out to detect a suspected conjunctival intraepithelial neoplasm. RESULTS: Tissue obtained from operation had cells with thin nuclei, spindle cells with pleomorphic cigar-shaped nuclei and eosinophilic cytoplasm, atypical cells, and from four to five mitotic figures under ten high power field. In immunohistochemical staining, Vimentin, Smooth muscle actin (SMA), Desmin, CD68 stained positively and cytokeratin, Cam5.2, S-100, HMB-45, CD 34 stained negatively. We found no clues of other origins from the general physical examination. Considering these factors, we conclude that this was a Stage I, G2T1aN0M0 leiomyosarcoma with moderate differentiation. CONCLUSIONS: Analysis by immunohistochemical staining is necessary to detect leiomyosarcoma in the conjunctiva, as it is very rare and hard to diagnose by the histologic method alone. We report a leiomyosarcoma of the conjunctiva after pterygium excision, and suggest that it be considered a differential diagnosis of conjunctival masses, even though it is very rare.

The Relationship Between Ascorbic Acid Concentration of Anterior Chamber and Complication in Alkali-Injured Rabbit Eyes

PURPOSE: To study the relationship between the concentration of ascorbic acid in the anterior chamber and the complications of an experimental alkali burn in rabbit corneas. METHODS: Standardized corneal alkali wounds were induced in both eyes of 33 albino rabbits by applying a 5.5 mm-sized round filter paper, soaked in 1N NaOH for 20 seconds. Then, the control group (22 eyes) was given Tears Natural II(R) (Alcon), treated group A (22 eyes) was given ascorbic acid (10%) for 2 hours, and treated group B (22 eyes) was given ascorbic acid (10%) for 6 hours. The concentrations of ascorbic acid in the anterior chamber were measured using a microplate assay immediately post-injury, and at 5 days, 15 days, and 30 days post-injury. During the experiment, clinical observation was performed to detect complications such as corneal ulcer or perforation. RESULTS: The incidence of ulceration was significantly lower between control group and treated groups A and B (p<0.05). The incidence of perforation was significantly lower in treated group A compared to the control group B (p<0.05). In addition, a higher concentration of ascorbic acid in the anterior chamber and a lower severity of corneal injury was significant (sigma=-0.302, P<0.05). CONCLUSIONS: Higher concentrations of ascorbic acid in the anterior chamber were associated with fewer complications in experimental alkali burns in rabbit corneas.

2001 Survey for KSCRS Members Current Trends in Cataract and Refractive Surgery in Korea

PURPOSE: We purposed to understand the current trends in the field of cataract and refractive surgery in Korea. METHODS: Since 1995, The members of the Korean Society of Cataract and Refractive Surgery (KSCRS) has annually surveyed on cataract and refractive surgery. 2002 annual survey forms which consists of 106 multiple-choice questions mailed to 358 members of the KSCRS. Approximately 35% of the members answered. Current data were compared with previous annual survey data and with those of Japan and USA. RESULTS: Duration of hospitalization has decreased annually and the use of topical anesthesia(35%) slightly decreased steadily. Self sealing wound construction was the main wound closure technique in phacoemulsification (35%). Acrylic intraocular lens in small incision cataract surgery was most preferred (48%). Seventy percent of the respondents performed excimer laser keratectomy. The most common complication of excimer laser was the regression of visual acuity (40%). Most respondents preferred LASIK regardless of diopter range. More respondents experienced legal problems associated with PRK or LASIK than those in last year survey. CONCLUSIONS: This survey summarized current trends and changes in cataract and refractive surgery in Korea are similar to those of Japan and USA.

2002 Survey for KSCRS Members: Current Trends in Cataract and Refractive Surgery in Korea

PURPOSE: Since 1995, we have annually surveyed the members of the Korean Society of Cataract and Refractive Surgery (KSCRS) on cataract surgery technique, anesthesia, intraocular lens and refractive surgery to understand the current situation and future trends in these fields. METHODS: Eighth annual survey forms consisted of 114 multiple-choice questions mailed in Feburary 2003 to 385 ophthalmologists of the KSCRS. Approximately 28.1% of the questionaires mailed were returned. Current data were compared with previous annual survey and data from Japan and USA. RESULTS: Hospitalized period is decreased annually and use of topical anesthesia (44%) increased. Self sealing wound construction was the main wound closure technique in phacoemulsification accounted for 54%. Most preferred intraocular lenses for small incision cataract surgery are acrylic (58%), increased highly. The number of members performing excimer laser keratomileusis for refractive surgery was increased (77%). Most respondants preferred LASIK without regard to diopter range. Legal problems on excimer laser and LASIK is in increased. The implantation of phakic IOL is performed by 17% of the members and 91% of members are interested in it. CONCLUSIONS: From this survey, we found current trend and change in cataract and refractive surgery in Korea are similar to those of Japan and USA.

Statistical Observation of the Inpatients Referred for Ophthalmologic Examination

PURPOSE: To study profiles of inpatients and eye problems evaluated and managed by the ophthalmology consultation service of a large university teaching hospital. METHODS: We evaluated one thousand fourteen patients from April 2002 through December 2002. We recorded demographic information, hospitalization information, and eye examination information, including reason for consultation, type of consultation, ophthalmologic diagnosis. RESULTS: Approximately half the patients were male. Patients in 7th decade were 199. Endocrinologic devision of internal medicine services accounted for 19.0% of all consultations. Twenty-two percent of all consultations was to rule out diabetic retinopathy. We recorded 64 primary ophthalmologic diagnoses and 40 secondary ophthalmologic diagnoses. The top five common primary ophthalmologic diagnoses were diabetic retinopathy, conjunctivitis, cataract, refractive error and dry eye. Cataract was the most common secondary ophthalmologic diagnosis. There were 266 primary hospital discharge diagnoses. The most common primary hospital discharge diagnosis was diabetes mellitus. CONCLUSIONS: . Many people requiring examination for diabetic retinopathy had no history of previous ophthalmic examination. Therefore, education for patients with diabetes mellitus is needed. This study profiled the typical patients and eye problems seen by an ophthalmologist when inpatient consultation is requested. We hope that this report provides a basic source for planning and management of consultation services in residency training programs.

Evaluation of Macular Circulation in Patient with Diabetic Maculopathy using Scanning Laser Ophthalmoscope(SLO)

In the condition of diabetic retinopathy, the vascular changes are localized primarily in the retinal capillaries and are presumed to promote angiogenesis. To investigate the change of retinal blood flow velocities and morphological parameters in diabetic retinopathy, we measured perifoveal capillary blood velocities(v) and the size of foveal avascular zones(FAZ). Thirteen patients with diabetic maculopathy and nine healthy volunteers were included in this study. The scanning laser technique in conjunction with an image analysing system were used to assess the morphological and hemodynamic changes in diabetic retinopathy. Diabetic maculopathy group showed a slower capillary blood velocity than normal group(2.44+/-0.39mm/sec vs2.75+/-0.61 mm/sec, p>0.18). The foveal avascular zone was significantly larger in diabetic maculopathy group than in normal group(313.5+/-64.6micrometervs. 238.9+/-93.8micrometer, p<0.05). This results indicate that the retinal microcirculation is altered in diabetic patients compared with healthy subjects. These alterations may be due to the change of the capillary wall and blood viscosity in diabetic patients. The determination of these parameters can be utilized in monitoring the progress of diabetic maculopathy.

A Case of Lymphangiomas(So-called Combined Venous Lymphatic Malformation) Resulting in Orbital Abscess

Orbital lymphangiomas are benign vascular hamartomas that may be found in the conjunctiva, the eyelids, the orbit, or elsewhere in the head and neck region. Deep lymphangiomatous lesions are classically characterized by acute onset of a fulminant proptosis resulting from spontaneous hemorrhage within the orbit. Complete surgical excision is often difficult because of the infiltrative nature of the tumor.We report one case of lymphangiomas considered to be associated with cavernous hemangioma which could not be removed completely by several surgical excisions and was exenterated because of orbital abscess of unknown origin and septic condition.