The saccadic reaction times to the double-step stimuli were studied in three human subjects to ascertain the saccadic visual tracking characteristics. Responses to simple step and double-step target motions were measured where the target mode and stimulus durations were randomized. To measure the eye movement the Photo-electric Eye Monitor was constructed based on limbus tracking. The results indicate that observers represented two kind of responses (A-or B-type) depending upon the stimulus duration. The percentage of occurrances increased as the stimulus duration increased from 50 to 200 msec. When the subject responded to both target motions, the reaction time of the second saccade was shorter than that of the first. The successive visual information is to change continuously the reaction time or cancel the initial saccade. Our results revealed that parallel data processing characteristics of the visual tracking systems and the saccadic decision-makings are influenced by the temporal relationships.
Adult ; Eye Movements* ; Human ; Male ; Motion Perception* ; Reaction Time* ; Saccades* ; Visual Perception*

A new method is described which uses photo-electric matrix method to measure two-dimensional eye movements. This system is composed of the detector unit (monitor), matrix and correction circuits and stimulus generator. A light and small detector unit attached to the modified trial frame transduces positional informations and can be achieved head-mounting. The instrument operates in the infrared, so that it does not interfere with normal vision, and over a two-dimensional visual field to +/-15 degrees. A system for generating a fixed target whose velocity, displacement, form, intensity, and other characteristics can be varied systematically also is described. The operating procedures are described and operating records are shown. Electrical and optical modifications of the present system will make possibIe the measurement of more smaller movement of the eye. Extensions and improvement of the technique of measurement are discussed briefly.
Eye Movements* ; Visual Fields

This study aims to investigate visual tracking task of Koreans to the various visual stimuli by measuring the horizontal saccadic reaction times. The measuring system consists of eye monitor using infra-red reflection technique, oscillographic recorder and forehead-chin fixation devices. The visual stimuli generated by target function generator displayed simple-step, pulsestep and double-step stimulus patterns. The results revealed that the sacoadic reaction time showed no significant changes between the size of target displacement within horizontal 20 degrees. Furthermore, no significant changes between the particular direction of stimulus could be found. The nominal value of reaction time was 259 +/- 25 msec.
Reaction Time

The authors have experienced with a case of orbital abscess that was thought to be an orbital tumor. The patient was a 5 year old Korean boy who had exophthalmos in the right eye, but he did not have definite signs of inflammation. On the orbital venogram, there was a space occupying lesion in the lateral and posterior portion of the right eye. To obtain the precise diagnosis of the lesion, we made a surgical approach and drainage of the pus was performed. The pus culture yielded coagulase-positive Staphylococcus. The literature relating to orbital abscess was briefly reviewed.
Abscess* ; Child, Preschool ; Diagnosis ; Drainage ; Exophthalmos ; Humans ; Inflammation ; Male ; Orbit* ; Staphylococcus ; Suppuration

This study aims to ascertain the human saccadic visual tracking characteristics by measuring the eye movement to the double-step stimuli. Responses to simple step and double-step target motions were measured where the target mode and stimulus durations were randomized. To measure the eye movement the Photo-electric Eye Monitor was constructed based on limbus tracking. The results indicate that observers represented two kind of responses (A-or B-type) depending upon the stimulus duration. The percentage of occurrances increased as the stimulus duration increased from 50 to 200 msec. When the subject responded to both target motions, the reaction time of the second saccade was shorter than that of the first. The successive visual information is to change continuously the reaction time or cancel the initial saccade. Our results revealed that parallel data processing characteristics of the visual tracking systems and the saccadic decision-makings are influenced by the temporal relationships.
Eye Movements ; Humans* ; Reaction Time ; Saccades

The purpose of this review is to examine the ways in which eye position and eye movements are measured in order to justify the choice of method for the study concerning the eye movement control systems. The oculomotor control systems were reviewed previously as a viewpoint of measuring objects. Because of the different aspects of eye movement which have been considered, various techniques have been developed-each having its own characteristics of range, sensitivity, bandwidth, stability and ease of application. This study is directed at discussing the pros and cons inherent in a basic method of measurement and to indicate the interesting historical development of oculography as new technologies were employed. Various methods are summarized and photo-electronic method(Limbus tracking technique) was chosen which is most available for the future experimentation.
Eye Movements*

BACKGROUND AND PURPOSE: This purpose of this research is to study the prevalence of habitual snoring and the association between snoring and cephalo-anthropometric analysis in Korean population. MATERIAL AND METHOD: Four thousand and two hundred twenty four subjects (male: 2277, female: 1947), aged between 18~85 (mean age male: 45.3, female: 44.0), were recruited through home visits and interviewed by well-trained investigators. RESULTS: Three hundred fifty two male subjects (15.5%) and one hundred sixty two female subjects (8.32%) exhibited habitual snoring. Age, weight, and body mass index (BMI) were significantly higher in the snoring group compared to those who dont snore habitually. Using a stepwise variable selection method of multiple logistic regression analysis, we found independent factors as being significant for males and females of the snoring groups. For males, the factors were BMI (p<0.001, OR=1.18 CI: 1.12~1.25), mandibular angle (p<0.001, OR=0.97 CI: 0.96~0.98), and abdominal girth (p<0.001, OR=1.04, CI: 1.02~1.06. For females, they were abdominal girth (p=0.031, OR=1.03, CI: 1.00~1.05), neck girth (p=0.003, OR=1.12, CI: 1.04~1.21), age (p=0.0002, OR=1.02 CI: 1.01~10.3), and BMI (p=0.0007, OR=1.11 CI: 1.05~1.18). CONCLUSION: We found that BMI, gonion angle and abdomen girth in male and abdominal girth, neck girth, age, BMI in female were the significant factors affecting the severity of snoring in Korean population.
Abdomen ; Adult* ; Body Mass Index ; Female ; House Calls ; Humans ; Logistic Models ; Male ; Neck ; Prevalence ; Research Personnel ; Sleep Apnea Syndromes ; Snoring*

BACKGROUND: Air pollution causes many diseases and deaths. It is important to see how air pollution affects obesity, which is common worldwide. Therefore, we analyzed data from a smartphone application for intentional weight loss, and then we validated them. METHODS: Our analysis was structured in two parts. We analyzed data from a cohort registered to a smartphone application in 10 large cities of the world and matched it with the annual pollution values. We validated these results using daily pollution data in United States and matching them with user information. Body mass index (BMI) variation between final and initial login time was considered as outcome in the first part, and daily BMI in the validation. We analyzed: daily calories intake, daily weight, daily physical activity, geographical coordinates, seasons, age, gender. Weather Underground application programming interface provided daily climatic values. Annual and daily values of particulate matter PM10 and PM2.5 were extracted. In the first part of the analysis, we used 2,608 users and then 995 users located in United States. RESULTS: Air pollution was highest in Seoul and lowest in Detroit. Users decreased BMI by 2.14 kg/m2 in average (95% confidence interval, −2.26 to −2.04). From a multilevel model, PM10 (β=0.04, P=0.002) and PM2.5 (β=0.08, P < 0.001) had a significant negative effect on weight loss when collected per year. The results were confirmed with the validation (βAQI*time=1.5×10–5; P < 0.001) by mixed effects model. CONCLUSION: This is the first study that shows how air pollution affects intentional weight loss applied on wider area of the world.
Air Pollution* ; Body Mass Index ; Cohort Studies ; Mobile Applications ; Motor Activity ; Obesity ; Particulate Matter ; Seasons ; Seoul ; Smartphone ; United States ; Weather ; Weight Loss

PURPOSE: Pertussis is a highly communicable infectious disease in children with high mortality, especially in young infants. The incidence of pertussis in South Korea has decreased to about 10 cases a year in late '90s. Doubting previously reported incidences of pertussis, we designed this study to establish exact epidemiology and a diagnostic basis of pertussis. METHODS: From Mar. 2000 to Mar. 2001, polymerase chain reaction(PCR) and cultures of nasopharyngeal aspirates were taken from 49 patients who were clinically suspected of pertussis in Kangdong Sacred Heart Hospital. RESULTS:Among 49 patients suspected of pertussis, 10 cases showed positive results by PCR method. Four out of those 10 cases were positive in culture. The peak outbreak was noticed in the spring(Mar.-May) and the autumn(Sep.-Nov.). The mean age of the patients was 3.6 months. Eight of the 10 cases which were PCR positive results proved not to be immunized against pertussis. CONCLUSION: Most of the pertussis patients in our study were diagnosed as bronchiolitis, pneumonia or bronchitis at the beginning of the disease and only a few patients showed typical clinical manifestations of pertussis, including whooping. When the above results are taken together, we suggest the possibility that the actual prevalence of pertussis in South Korea might be higher than that of previous reports. The importance of pertussis screen tests should be emphasized in children with severe coughs.
Bronchiolitis ; Bronchitis ; Child* ; Communicable Diseases ; Cough ; Epidemiology ; Heart ; Humans ; Incidence ; Infant ; Korea ; Mortality ; Pneumonia ; Polymerase Chain Reaction ; Prevalence ; Whooping Cough*

Background: Only a few studies have established the epidemiology of prolactinoma and Cushing’s disease in Korea. Furthermore, the incidence of these disease are increasing than before associated with the development of technologies. This study was designed to evaluate the epidemiology of prolactinoma and Cushing’s disease and their survival analysis according to treatment. Methods: The nationwide, population-based study evaluated incidence and prevalence of prolactinoma and Cushing’s disease using de-identified claims data in The Korean Health Insurance Review and Assessment Service database between 2013 and 2017. The survival analysis investigated regarding treatment over a period of 6 years. A log-rank test and Cox proportional hazard regression analysis were used. Results: The 6,056 patients with newly diagnosed prolactinoma and 584 patients with Cushing’s disease were recorded between 2013 and 2017. The annual incidence of prolactinoma was 23.5 cases per million, and its prevalence was 82.5 cases per million, and 2.3 cases per million/year and 9.8 cases per million for Cushing’s disease. The survival benefit was insignificant in prolactinoma according to treatment, but treatment of Cushing’s disease ameliorated the survival rate significantly. Conclusion Overall, the incidence of prolactinoma and Cushing’s disease was similar with those found previously, but the prevalence of two diseases were inconsistent when compared with the early studies. The present study also proposed necessity of treatment in Cushing’s disease for improving the survival rate.