An Overview of the Korean Intermittent Exotropia Multicenter Study by the Korean Association for Pediatric Ophthalmology and Strabismus

The Korean Intermittent Exotropia Multicenter Study (KIEMS), which was initiated by the Korean Association of Pediatric Ophthalmology and Strabismus, is a collaborative multicenter study on intermittent exotropia in Korea. The KIEMS was designed to provide comprehensive information, including subjective and objective findings of intermittent exotropia in a large study population. A total of 65 strabismus specialists in 53 institutions contributed to this study, which, to date, is one of the largest clinical studies on intermittent exotropia. In this article, we provide a detailed methodology of the KIEMS to help future investigations that may use the KIEMS data.

An Overview of the Korean Intermittent Exotropia Multicenter Study by the Korean Association for Pediatric Ophthalmology and Strabismus

The Korean Intermittent Exotropia Multicenter Study (KIEMS), which was initiated by the Korean Association of Pediatric Ophthalmology and Strabismus, is a collaborative multicenter study on intermittent exotropia in Korea. The KIEMS was designed to provide comprehensive information, including subjective and objective findings of intermittent exotropia in a large study population. A total of 65 strabismus specialists in 53 institutions contributed to this study, which, to date, is one of the largest clinical studies on intermittent exotropia. In this article, we provide a detailed methodology of the KIEMS to help future investigations that may use the KIEMS data.

A Novel Method for Hyperacuity Measurement

PURPOSE: We developed a novel method for measurement of hyperacuity and verified the utility thereof.METHODS: We developed a three-dimensional (3D) hyperacuity test using a 3D liquid crystal flat screen, a left- and right-image polarized display, and liquid crystal shutter glasses. We tested the technique in three groups: normal (n = 48), with cataracts (n = 14), and with macular disease (n = 35). We used a chart consisting of five dots and a reference line. Of the five dots, one was variably shifted from the other dots. A chart was presented to one eye and the reference line or blank image to the other eye; a subject scored positive when the dot in the unusual position was recognized.RESULTS: Hyperacuity was measured in terms of the reference line seen by the reference eye (RR), a blank image seen by the reference eye (RB), the reference line seen by the contralateral eye (CR), and a blank image seen by the contralateral eye (CB). All test scores were significantly lower when the reference line was seen than not (RR vs. RB and CR vs. CB; p < 0.01, respectively). For the RR and CR tests, no significant difference was apparent between the normal and cataracts group (p = 0.553, p = 0.494) but such differences were evident between the normal and macular disease groups (p = 0.028, p = 0.002). Also, visualization of the reference line by the reference and contralateral eyes did not differ (p > 0.05).CONCLUSIONS: Measurement of hyperacuity using our new method was not affected by media opacity but was significantly affected by macular disease. Presentation of a reference line facilitated hyperacuity assessment.

Unilateral Ptosis with Bilateral Incomplete Ophthalmoplegia as the Initial Presentation in Metastatic Cancer / 이화의대지

Orbital metastases are rare and predominantly unilateral occurrences. Bilateral metastases affecting the extraocular muscles are extremely rare. A few case reports of bilateral metastases to extraocular muscles described binocular diplopia with conspicuous bilateral external ophthalmoplegia as an initial symptom. We report a case in which unilateral ptosis was an initial symptom and bilateral incomplete ophthalmoplegia was found on initial neurologic examination in invasive ductal carcinoma of the breast. The patient had hormone receptor-positive breast cancer, and so was treated by hormonal therapies and closely monitored. The presence of a secondary orbital lesion presents many difficulties of differential diagnosis and treatment. A thorough neurologic examination to detect ocular manifestations is most important for localization and broad differential diagnosis including mechanical orbital metastatic lesion.

A Case of Immediate Surgical Repair in Traumatic Isolated Inferior Rectus Muscle Rupture

PURPOSE: We report a case of infraduction limitation improvement and orthotropia at primary position in a patient with traumatic isolated inferior rectus muscle rupture after immediate repair surgery of the ruptured muscle. CASE SUMMARY: A 47-year-old man came to our emergency department complaining of right eyelid contusion and conjunctival laceration after trauma due to the metal part of a high pressure hose. Right hypertropia of 20 prism diopters was observed at primary gaze and right hypertropia of 30 prism diopters was observed at down gaze. The right eye showed a -4 infraduction limitation. We sutured the distal part of the ruptured inferior rectus muscle with surrounding tissue, including the Tenon's capsule and the part of the muscle stump, to its original insertion. Orthotropia at primary position and 8-prism-diopters of right hypertropia on down gaze was observed one day after surgery. At 40 days after surgery, the patient had orthotropia at primary position and 4-prism-diopter right hypertropia on down gaze. Infraduction limitation of the right eye improved to -1. CONCLUSIONS: Immediate repair of complete traumatic isolated inferior rectus muscle rupture can correct the limitation of extraocular movement and achieve orthotropia at primary position.

Prevalence and Factors Associated with the Use of Eye Care Services in South Korea: Korea National Health and Nutrition Examination Survey 2010–2012

PURPOSE: To estimate the factors and prevalence of eye care service utilization in the South Korean population. METHODS: This cross-sectional, population-based study included data from 22,550 Koreans aged ≥5 years who participated in the Korea National Health and Nutrition Examination Survey from 2010 to 2012. For people aged 5 to 11 years (young children), information was based on self-reports of contact with eye care service in the past year; for people aged ≥12 years (older population), the information was based on the self-reported lifetime contact with eye care service. Univariate and multivariate logistic regression analyses of the complex sample survey data were performed. RESULTS: The prevalence of eye care service use in young children during the past year was 61.1% (95% confidence interval, 58.1%–64.1%), while that in the older population during their lifetime was 73.5%. Subjects aged 7 to 11 years were more likely to have had an eye examination in the past year than subjects aged 5 to 6 years (odds ratio, 3.83; 95% confidence interval, 2.37–6.19). Multivariate logistic regression analysis indicated that higher monthly household income, being a National Health Insurance holder, and having private health insurance were related to more frequent use of eye care services in young children. For the older population and women, those living in an urban area and those with a best-corrected visual acuity less than 20 / 40 in the worse-seeing eye were more likely to have had an eye examination during their lifetime. Low education level was associated with low lifetime use of eye care services in the older population. CONCLUSIONS: There are sociodemographic disparities with use of eye care services in South Korea. This population-based study provides information that is useful for determining different intervention programs based on sociodemographic disparities to promote eye care service utilization in South Korea.

Two cases of methyl alcohol intoxication by sub-chronic inhalation and dermal exposure during aluminum CNC cutting in a small-sized subcontracted factory

BACKGROUND: Methyl alcohol poisoning has been mainly reported in community. Two cases of methyl alcohol poisoning occurred in a small-sized subcontracted factory which manufactured smartphone parts in Korea. CASE PRESENTATION: One young female patient presented with dyspnea and visual disturbance. Another young male patient presented with visual disturbance and myalgia. They treated with sodium bicarbonate infusion and hemodialysis for metabolic acidosis. In addition, he received ethyl alcohol per oral treatment. Her and his urinary methyl alcohol concentration was detected as 7.632 mg/L, 46.8 mg/L, respectively, although they were treated hemodialysis. Results of the working environment measurement showed that the concentration of methyl alcohol (1030.1–2220.5 ppm) in the air exceeded the time weighted average (200 ppm). They were diagnosed with optic neuropathy due to methyl alcohol poisoning and still have visual impairment. CONCLUSIONS: Workers who hired as dispatched employees in a small-sized subcontracted factory were exposed to high concentrations of methyl alcohol. The workplace had poor ventilation system. In addition, workers did not wear proper personal protect equipment. Working environment measurement and annual chekups for workers were not performed. They were in a blind spot to occupational safety and health. More attention is needed to protect vulnerable workers’ health.

Refractive Errors in Koreans: The Korea National Health and Nutrition Examination Survey 2008-2012

PURPOSE: Our study provides epidemiologic data on the prevalence of refractive errors in all age group ≥5 years in Korea. METHODS: In 2008 to 2012, a total of 33,355 participants aged ≥5 years underwent ophthalmologic examinations. Using the right eye, myopia was defined as a spherical equivalent (SE) less than -0.5 or -1.0 diopters (D) in subjects aged 19 years and older or as an SE less than -0.75 or -1.25 D in subjects aged 5 to 18 years according to non-cycloplegic refraction. Other refractive errors were defined as follows: high myopia as an SE less than -6.0 D; hyperopia as an SE larger than +0.5 D; and astigmatism as a cylindrical error less than -1.0 D. The prevalence and risk factors of myopia were evaluated. RESULTS: Prevalence rates with a 95% confidence interval were determined for myopia (SE <-0.5 D, 51.9% [51.2 to 52.7]; SE <-1.0 D, 39.6% [38.8 to 40.3]), high myopia (5.0% [4.7 to 5.3]), hyperopia (13.4% [12.9 to 13.9]), and astigmatism (31.2% [30.5 to 32.0]). The prevalence of myopia demonstrated a nonlinear distribution with the highest peak between the ages of 19 and 29 years. The prevalence of hyperopia decreased with age in subjects aged 39 years or younger and then increased with age in subjects aged 40 years or older. The prevalence of astigmatism gradually increased with age. Education was associated with all refractive errors; myopia was more prevalent and hyperopia and astigmatism were less prevalent in the highly educated groups. CONCLUSIONS: In young generations, the prevalence of myopia in Korea was much higher compared to the white or black populations in Western countries and is consistent with the high prevalence found in most other Asian countries. The overall prevalence of hyperopia was much lower compared to that of the white Western population. Age and education level were significant predictive factors associated with all kinds of refractive errors.

An Overview of Ophthalmologic Survey Methodology in the 2008-2015 Korean National Health and Nutrition Examination Surveys

The Korea National Health and Nutrition Examination Survey (KNHANES) is a national program designed to assess the health and nutritional status of the noninstitutionalized population of South Korea. The KNHANES was initiated in 1998 and has been conducted annually since 2007. Starting in the latter half of 2008, ophthalmologic examinations were included in the survey in order to investigate the prevalence and risk factors of common eye diseases such as visual impairment, refractive errors, strabismus, blepharoptosis, cataract, pterygium, diabetic retinopathy, age-related macular degeneration, glaucoma, dry eye disease, and color vision deficiency. The measurements included in the ophthalmic questionnaire and examination methods were modified in the KNHANES IV, V, and VI. In this article, we provide detailed information about the methodology of the ophthalmic examinations in KNHANES in order to aid in further investigations related to major eye diseases in South Korea.

A Case of Invasive Aspergillosis Involving the Orbital Apex and Occipital Lobe:Successful Treatment with Voriconazole

PURPOSE: To report an immunocompetent patient with more than 1-year survival after treatment with voriconazole, despite invasive paranasal sinus aspergillosis involving the orbital apex. CASE SUMMARY: A 74-year-old woman with only preexisting hypertension visited our clinic complaining of pain and immovable left eye that occurred approximately 4 days prior. Computed tomography (CT) and magnetic resonance imaging (MRI) showed a sphenoid sinusitis with suspicious lesion involving the orbital apex of the left eye. A biopsy by functional endoscopic sphenoid surgery (FESS) was performed through the sphenoid sinus, which enabled us to diagnose aspergillosis. The patient had esotropia, ophthalmoplegia, positive RAPD, and ptosis in the left eye. On follow-up, a new MRI showed acute to subacute stage infarction at the left occipital lobe. After the patient was treated with intravenous voriconazole, ptosis, and ophthalmoplegia improved. At the 13-month follow-up, she was alive with no disease recurrence. CONCLUSIONS: Invasive aspergillosis of orbit and cerebrum in healthy patients is a rare clinical entity. In case of central nervous system involvement, the survival outcome is poor with high mortality; however, good results can be obtained by treatment with voriconazole.

Diagnostic Criteria of Pattern VEP in Adult Monocular Amblyopic Patients

PURPOSE: To suggest a diagnostic criteria of pattern visual evoked potential (VEP) in adult monocular amblyopic patients in comparison to normal subjects. METHODS: The medical records of patients' military service certificates from January 2000 to December 2011 were reviewed. The parameters of pattern VEP were analyzed by comparing monocular amblyopic patients with normal controls. RESULTS: This study included 47 monocular amblyopia and 39 normal control patients. All parameters of pattern VEP were statistically significantly different between monocular amblyopic eyes and normal eyes. The cut-off values for diagnosis of adult amblyopia using receiver operating characteristic (ROC) curve were 113.50 msec (P100 latency), 1.05 (ratio of P100 latency), 8.50 msec (interocular difference of P100 latency), and 5.25 microV (interocular difference of P100 amplitude). Cut-off value sensitivities were generally low: (51.1%, 70.2%, 53.2%, and 31.9%, respectively). CONCLUSIONS: The value of pattern VEP parameters had limitations due to low sensitivity and could be considered as ancillary diagnostic criteria when diagnosing amblyopia.

Predictive Factors of Successful Weaning From Glasses in Accommodative Esotropia Patients

PURPOSE: To investigate the predictive factors of successfully weaning children from glasses with accommodative esotropia who were monitored with manifest refraction on follow-up visits. METHODS: A retrospective review of 48 patients with accommodative esotropia was performed. Weaning was accomplished by monitoring patients with manifest refraction on follow-up visits. The patients were divided into 2 groups: patients who were weaned successfully from glasses and patients who still needed glasses at their final visit. A comparative analysis of the multiple clinical features between the 2 groups was performed. RESULTS: Among the 48 patients, 15 patients were weaned successfully from glasses. The age of onset was significantly different between the 2 groups, 39.6 +/- 14.9 months in patients who were weaned successfully from glasses and 30.7 +/- 16.9 months in patients who still needed glasses. In particular, the patients with onset of accommodative esotropia after 3 years of age were more likely to be weaned from glasses at their final visit. CONCLUSIONS: Monitoring with manifest refraction could be another method of weaning children from glasses with accommodative esotropia and the age of onset appears to be the useful predictor of successful weaning in children who can finally be weaned from glasses.

Prevalence of Eye Diseases in South Korea: Data from the Korea National Health and Nutrition Examination Survey 2008-2009

PURPOSE: The aim of this study is to report on preliminary data regarding the prevalence of major eye diseases in Korea. METHODS: We obtained data from the Korea National Health and Nutrition Examination Survey, a nation-wide cross-sectional survey and examinations of the non-institutionalized civilian population in South Korea (n = 14,606), conducted from July 2008 to December 2009. Field survey teams included an ophthalmologist, nurses, and interviewers, traveled with a mobile examination unit and performed interviews and ophthalmologic examinations. RESULTS: The prevalence of visual impairment, myopia, hyperopia and astigmatism in participants over 5 years of age was 0.4 +/- 0.1%, 53.7 +/- 0.6%, 10.7 +/- 0.4%, and 58.0 +/- 0.6%, respectively. The prevalence of strabismus and blepharoptosis in participants over 3 years of age was 1.5 +/- 0.1% and 11.0 +/- 0.8%, respectively. In participants over 40 years of age, the prevalence of cataract, pterygium, early and late age-related macular degeneration, diabetic retinopathy and glaucoma was 40.2 +/- 1.3%, 8.9 +/- 0.5%, 5.1 +/- 0.3%, 0.5 +/- 0.1%, 13.4 +/- 1.5%, and 2.1 +/- 0.2%, respectively. CONCLUSIONS: This is the first nation-wide epidemiologic study conducted in South Korea for assessment of the prevalence of eye diseases by both the Korean Ophthalmologic Society and the Korea Center for Disease Control and Prevention. This study will provide preliminary information for use in further investigation, prevention, and management of eye diseases in Korea.

Horner's Syndrome with Abducens Nerve Palsy

A 68-year-old male patient presented with a week of sudden diplopia. He had been diagnosed with nasopharyngeal cancer 8 months prior and had undergone chemotherapy with radiotherapy. Eight-prism diopter right esotropia in the primary position and a remarkable limitation in abduction in his right eye were observed. Other pupillary disorders and lid drooping were not found. After three weeks, the marginal reflex distance 1 was 3 mm in the right eye and 5 mm in the left eye. The pupil diameter was 2.5 mm in the right eye, and 3 mm in the left eye under room illumination. Under darkened conditions, the pupil diameter was 3.5 mm in the right eye, and 5 mm in the left eye. After topical application of 0.5% apraclonidine, improvement in the right ptosis and reversal pupillary dilatation were observed. On brain magnetic resonance imaging, enhanced lesions on the right cavernous sinus, both sphenoidal sinuses, and skull base suggested the invasion of nasopharyngeal cancer. Lesions on the cavernous sinus need to be considered in cases of abducens nerve palsy and ipsilateral Horner's syndrome.

Clinical Features of the Sixth Cranial Nerve Palsy

PURPOSE: To evaluate the clinical features and natural course of sixth cranial nerve palsy. METHODS: We reviewed the medical records of 50 patients who were diagnosed with sixth nerve palsy from January 2000 to December 2006 to analyze the age of onset, etiology, recovery, and natural course of this disease. RESULTS: The mean age at onset was 43.2 years old. Vascular disease (n=17, 34.0%) was the most common cause of sixth cranial nerve palsy, followed by undetermined causes (n=14, 28.0%), trauma (n=10, 20.0%), and neoplasm (n=3, 6.0%). According to age group, vascular disease (n=7, 46.7%) was the most common cause in patients in their fifties and sixties, and trauma and undetermined causes (n=10, 76.9%) were the most common causes of this disease in patients in their twenties and thirties. Of the 40 patients who were followed up for more than 6 months, 28 (70.0%) showed improvement of paresis and 26 (65.0%) achieved complete recovery. The mean period to recovery was 3.7 months. No significant differences were observed in sex, age, laterality, and etiology between non-recovered and completely-recovered patients, but completely-recovered patients showed a significantly smaller initial angle of deviation than non-recovered patients. CONCLUSIONS: Vascular disease was the most common etiology of sixth nerve palsy. Sixty-five percent of patients showed spontaneous complete recovery, and completely-recovered patients showed a significantly smaller initial angle of deviation compared to that of non-recovered patients.

Clinical Characteristics of the Patients Referred to Ophthalmic Clinic for Medical Disability Evaluation

PURPOSE: To investigate the clinical characteristics and disability rates of patients seeking expert consultation for legal reasons because of ophthalmologic symptoms. METHODS: We analyzed the gender, age, reason for consultation, and result of consultation, among other factors, by retrospectively examining the medical files of 89 patients from January 1999 to December 2004. RESULTS: Out of 89 patients, men constituted 76.4% and patients in their forties constituted 23.0%. The most common reason for consultation was a traffic accident (64.0%), followed by a medical lawsuit (11.2%). Forty-nine patients (55.1%) were diagnosed with a disability, while 30 patients (33.7%) were not. Diagnostic decisions for the other 10 patients (11.2%) were deferred. Optic atrophy was the most frequent cause for deteriorating visual acuity in patients, accounting for 19 cases, and diplopia caused by orbital wall fracture was also prevalent (9 patients). Among the resulting types of damage, brain damage was the most frequent, while the percentage of patients with an impairment in the visual system was approximately 29.0% among the patients diagnosed with a disability. CONCLUSIONS: Our results will be helpful in elucidating the clinical characteristics of patients referred to the ophthalmic clinic for consultation because of legal concerns.

The Range of Ocular Torsion in Mass Screening

PURPOSE: To determine the range of cyclotorsion in the mass screening of patients by studying the spatial relationship between the optic disc and the fovea. METHODS: We examined the horizontal and vertical distances from the center of the optic disc to the fovea using the fundus photographs of 249 subjects (498 eyes) without a past history of strabismus through mass screening and then calculated the optic disc-foveal angle. We studied the differences in all the measured parameters between the right and left eyes and between men and women. RESULTS: The horizontal distance from the center of the optic disc to the fovea was 2.59+/-0.26 DD (disc diameter) in the right eye and 2.58+/-0.27 DD in the left eye. The mean horizontal distance was 2.59+/-0.26 DD. The vertical distance from the center of the optic disc to the fovea was 0.28+/-0.14 DD in the right eye and 0.30+/-0.13 DD in the left eye. The mean vertical distance was 0.29+/-0.14 DD. The calculated disc-foveal angle was 6.26+/-2.98 degrees in the right eye and 6.69+/-2.84 degrees in the left eye (mean, 6.50+/-2.92 degrees). There were no significant differences between the right and left eyes or between males and females. The 95% range of the location of the fovea was from 0.01 DD to 0.57 DD inferior to the optic disc center. CONCLUSIONS: We concluded that the clinical location of the fovea, as measured in the mass screening, extends from the center of the optic disc to the lower edge of the optic disc.

Related Factors of Surgical Outcome of Unilateral R and R for Basic Type Intermittent Exotropia in Children

PURPOSE: To study the associated factors with surgical success of intermittent exotropia of basic type in children. METHODS: The medical records of 58 children with intermittent exotropia treated with unilateral recession of lateral rectus muscle and resection of the medial rectus muscle and having at least 6 months of follow-up were reviewed. These surgical results were analyzed to assess the association with preoperative factors including sex, photophobia, stereopsis, vertical deviation, time of surgery and preoperative angle of deviation and early postoperative changes in motor alignment which were documented at 2 days, 1 week and 1 month after the surgery. RESULTS: There was significant difference between the early postoperative overcorrection group and others(P<0.05). The overcorrection of 10-20PD showed higher success rate than the overcorrection of 1-9PD at postoperative 1 week. Any preoperative patients' characteristics were not related to surgical outcome. CONCLUSIONS: Early postoperative overcorrection is associated with the good surgical result and the overcorrection of 10-20PD at 1 week can be the predictive factor of better surgical outcome.

Efficacy of Occlusion Therapy in Amblyopia: Type, Depth and Timing of Amblyopia

PURPOSE: To study the effect of occlusion therapy in amblyopia according to the beginning time of occlusion therapy, type and depth of amblyopia. METHODS: The total 92 children, who had been treated with occlusion therapy were included in this study. Patients were divided into two groups according to the age when occlusion therapy was started: those with less than 7 years vs 7 years or older. Patients were also divided into three groups according to the type of amblyopia and depth of amblyopia: mild amblyopia with visual acuity 0.6 or more , moderate amblyopia with between 0.2 and 0.5 , and severe amblyopia with 0.1 or less. RESULTS: The children under 7 years old were 58 patients and 7 years or over was 34 patients. In patients less than 7 years, 70.7% achieved a successful treatment and in patients 7 years or more, 67.6% was in success. There was no significant difference between two groups. Among the moderate and severe amblyopic patients, 72.1% of patients under 7 year-old and of 44.4% of over 7 year-old achieved a successful treatment. According to the type of amblyopia, there was no significant difference between the groups. According to the depth of amblyopia, success rate of occlusion in mild, moderate and severe amblyopia was 80.6%, 67.9%, and 37.5% respectively. CONCLUSIONS: The success rate was higher in younger group than older group in moderate and severe amblyopia. The depth of amblyopia affected the final visual outcome, and occlusion therapy was more effective in less severe amblyopia.

Reliability of the Dynamic Stereoacuity using New Personal Computer Program

PURPOSE: We performed this study to evaluate the reliability of dynamic stereoacuity test with new personal computer program. METHODS: Twenty subjects (5 men, 15 women) were examined for dynamic stereo-threshold measured by new computer program at 94cm test distance. On fifty tested subjects, variant dynamic stereoacuity was created with the random spherical lenses from +0.5 to +3.0 diopter before the right eye. To evaluate the intraobserver reliability of the test, stereoacuity was measured five times on five separate days by the same examiner. To evaluate the interobserver reproducibility, stereoacuity was measured two times by two different examiners. RESULT: The Cronbach's alpha (internal consistency) of intraobserver was 0.99 (P<0.001). The Spearman correlation coefficient of interobserver was 0.99 (P<0.001). CONCLUSION: This method of dynamic stereoacuity measurement has a high reliability.