Tyler Hyungtaek Rim

Retinal vein occlusion and the risk of stroke development: a 9-year nationwide population-based study.

PURPOSE To evaluate the risk of stroke development after retinal vein occlusion (RVO). DESIGN Nationwide, population-based 9-year longitudinal study. PARTICIPANTS National registry data were collected from the Korean National Health Insurance Research Database, comprising 1 025 340 (∼2.2%) random subjects who were selected from 46 605 433 Korean residents in 2002. METHODS Patients diagnosed with RVO or stroke in 2002 were excluded. The RVO group was composed of patients with an initial diagnosis of central or branch RVO between January 2003 and December 2005 (n = 344 in 2003, 375 in 2004, and 312 in 2005). The comparison group was composed of randomly selected patients (5 per patient with RVO; n = 1696 in 2003, 1854 in 2004, and 1524 in 2005) who were matched to the RVO group according to age, sex, residential area, household income, and year of RVO diagnosis. Each sampled patient was tracked until 2010. Cox proportional hazard regressions were used to calculate the overall survival rate for stroke development after adjusting for potential confounders, including hypertension, diabetes mellitus, and chronic kidney disease. MAIN OUTCOME MEASURES Retinal vein occlusion and ischemic or hemorrhagic stroke based on the International Classification of Disease codes. RESULTS Stroke developed in 16.8% of the RVO group and in 10.7% of the comparison group. Retinal vein occlusion was associated with an increased risk of stroke development (hazard ratio [HR], 1.48; 95% confidence interval [CI], 1.24-1.76). Hypertension, diabetes mellitus, and chronic kidney disease also increased the risk of stroke development. In addition, RVO increased the risk of both ischemic stroke (HR, 1.51; 95% CI, 1.24-1.84) and hemorrhagic stroke (HR, 1.30; 95% CI, 0.83-2.05), although this result was not significant for hemorrhagic stroke. In terms of age, the effect size of the HR was largest among younger adults, aged <50 years (HR, 2.69), compared with middle-aged adults, aged 50 to 69 years (HR, 1.33), and older adults, aged ≥70 years (HR, 1.46). CONCLUSIONS Retinal vein occlusion was significantly associated with stroke development after adjusting for potential confounders. These findings are limited by uncontrolled confounding and need to be replicated by other observational studies.

Prevalence of and Risk Factors Associated With Dry Eye: The Korea National Health and Nutrition Examination Survey 2010-2011

PURPOSE To investigate the prevalence of and risk factors associated with dry eye syndrome (DES) in South Korea. DESIGN Cross-sectional study. METHODS In 2010 and 2011, 11,666 subjects, ranging in age from 19 to 95, were randomly selected as nationally representative participants in the Korea National Health and Nutrition Examination Survey (KNHANES). Subjects were divided into 2 groups: 1 with clinically diagnosed DES and 1 with symptoms of dry eye. We determined the prevalence of and risk factors for dry eyes in a Korean population. Health-related quality of life (HRQoL), measured by the EuroQoL-5 dimension (EQ-5D), was evaluated in patients with dry eyes. RESULTS The mean age was 49.9 years. The overall prevalence of diagnosed DES was 8.0% (95% confidence interval [CI], 7.3% to 8.7%), and of dry eye symptoms the prevalence was 14.4% (95% CI, 13.1 to 15.7). Age (adjusted odds ratio [aOR] = 1.8, 1.6), female (aOR = 2.8, 1.9); history of eye surgery (aOR = 2.6, 2.2); stress (aOR = 1.7, 1.6); thyroid disease (aOR = 1.7, 1.5); and high education level (aOR = 1.6, 1.5) were common risk factors in the groups. Subjects who had undergone ptosis, cataract or refractive surgery were more likely to have dry eye than subjects with no history of eye surgery. Means of pain and anxiety dimensions in the EQ-5D and the Euro Quality of Life Visual Analog Scale (EQ-VAS) were significantly higher in the group with diagnosed DES than in the normal group. CONCLUSIONS The risk factors were mostly similar in both groups. It is thought there are more patients with DES who have not been diagnosed by doctors. Doctors should identify whether a patient has any risk factors for dry eye. Patients need to be educated about the modifiable factors of DES.

Risk factors associated with pterygium and its subtypes in Korea: the Korean National Health and Nutrition Examination Survey 2008-2010.

Purpose: To assess the sociodemographic and health-related risk factors associated with pterygium and its subtypes in Korea. Methods: From 2008 to 2010, a total of 14,920 randomly selected national representative participants of the Korean National Health and Nutrition Examination Survey underwent additional ophthalmologic examinations by the Korean Ophthalmologic Society. The risk factors for pterygium in general or according to subtype (atrophic, intermediate, and fleshy) were identified using multivariate logistic regression analysis. Results: The prevalence of pterygium was 6.7% (95% confidence interval, 5.9–7.5) in subjects aged 30 years or older. Older age, male sex, lower educational level, rural habitation, nonsmoking, and sun exposure were independent risk factors for pterygium. Among subjects with pterygium, older age, male sex, lower educational level, and nonsmoking were independent risk factors for all types of pterygium. Sun exposure for >5 h/d was the independent risk factor for the severe pterygium subtype. Conclusions: Socioeconomic disparities in pterygium development exist. Proper ocular examination and education to avoid excessive sun exposure would be helpful in reducing disease risk.

Prevalence and risk factors of visual impairment and blindness in Korea: the Fourth Korea National Health and Nutrition Examination Survey in 2008-2010.

To describe the age, gender specific prevalence and risk factors of visual impairment and blindness in Korea.

The Added Prognostic Value of Preoperative Dynamic Contrast-Enhanced MRI Histogram Analysis in Patients with Glioblastoma: Analysis of Overall and Progression-Free Survival

BACKGROUND AND PURPOSE: The prognostic value of dynamic contrast-enhanced MR imaging in patients with glioblastoma is controversial. We investigated the added prognostic value of dynamic contrast-enhanced MR imaging to clinical parameters and molecular biomarkers in patients with glioblastoma by using histogram analysis. MATERIALS AND METHODS: This retrospective study consisted of 61 patients who underwent preoperative dynamic contrast-enhanced MR imaging for glioblastoma. The histogram parameters of dynamic contrast-enhanced MR imaging, including volume transfer constant, extravascular extracellular volume fraction, and plasma volume fraction, were calculated from entire enhancing tumors. Univariate analyses for overall survival and progression-free survival were performed with preoperative clinical and dynamic contrast-enhanced MR imaging parameters and postoperative molecular biomarkers. Multivariate Cox regression was performed to build pre- and postoperative models for overall survival and progression-free survival. The performance of models was assessed by calculating the Harrell concordance index. RESULTS: In univariate analysis, patients with higher volume transfer constant and extravascular extracellular volume fraction values showed worse overall survival and progression-free survival, whereas plasma volume fraction showed no significant correlation. In multivariate analyses for overall survival, the fifth percentile value of volume transfer constant and kurtosis of extravascular extracellular volume fraction were independently prognostic in the preoperative model, and kurtosis of volume transfer constant and extravascular extracellular volume fraction were independently prognostic in the postoperative model. For progression-free survival, independent prognostic factors were minimum and fifth percentile values of volume transfer constant and kurtosis of extravascular extracellular volume fraction in the preoperative model and kurtosis of extravascular extracellular volume fraction in the postoperative model. The performance of preoperative models for progression-free survival was significantly improved when minimum or fifth percentile values of volume transfer constant and kurtosis of extravascular extracellular volume fraction were added. CONCLUSIONS: Higher volume transfer constant and extravascular extracellular volume fraction values are associated with worse prognosis, and dynamic contrast-enhanced MR imaging may have added prognostic value in combination with preoperative clinical parameters, especially in predicting progression-free survival.

Influence of visual acuity on suicidal ideation, suicide attempts and depression in South Korea

Background To assess the influence of visual acuity (VA) on suicidal ideation, suicide attempts and depression. Methods From 2008 to 2012, a total of 28 919 nationally representative participants aged 19 years or older in the Korea National Health and Nutrition Examination Survey underwent additional ophthalmological examinations by the Korean Ophthalmologic Society. Associations between best corrected VA in the better-seeing eye based on decimal fraction and mental health were identified using multivariable logistic regression analysis after adjusting for possible biopsychosocial confounders. Self-reported mental health (suicidal ideation, suicide attempt and depression), Euro Quality of Life-Visual Analog Scale and counselling experience were evaluated by direct interviews. A nomogram for risk of suicidal ideation was generated. Results By multivariable logistic regression analysis, low VA was significantly associated with suicidal ideation and suicide attempt but not depression. Participants with a VA of no light perception to 0.2 had a nearly twofold and threefold increased risk of suicidal ideation (adjusted OR, 1.85; 95% CI 1.04 to 3.27) and suicidal attempt (adjusted OR, 3.44; 95% CI 0.92 to 12.79), compared with participants with a VA of 1.0. Sociodemographic disparities, including age and socioeconomic status, existed for suicidal ideation, suicidal attempt and depression. Euro Quality of Life-Visual Analog Scale significantly decreased as VA decreased and was lower in participants who attempted suicide. Conclusions Low VA was associated with the occurrence of suicidal ideation or a suicide attempt. Ophthalmologists should embrace their responsibility to help reduce suicidality and prevent suicides in patients with low VA by encouraging them to seek psychiatric care.

Incremental Prognostic Value of ADC Histogram Analysis over MGMT Promoter Methylation Status in Patients with Glioblastoma

Purpose To investigate the incremental prognostic value of apparent diffusion coefficient (ADC) histogram analysis over oxygen 6-methylguanine-DNA methyltransferase (MGMT) promoter methylation status in patients with glioblastoma and the correlation between ADC parameters and MGMT status. Materials and Methods This retrospective study was approved by institutional review board, and informed consent was waived. A total of 112 patients with glioblastoma were divided into training (74 patients) and test (38 patients) sets. Overall survival (OS) and progression-free survival (PFS) was analyzed with ADC parameters, MGMT status, and other clinical factors. Multivariate Cox regression models with and without ADC parameters were constructed. Model performance was assessed with c index and receiver operating characteristic curve analyses for 12- and 16-month OS and 12-month PFS in the training set and validated in the test set. ADC parameters were compared according to MGMT status for the entire cohort. Results By using ADC parameters, the c indices and diagnostic accuracies for 12- and 16-month OS and 12-month PFS in the models showed significant improvement, with the exception of c indices in the models for PFS (P < .05 for all) in the training set. In the test set, the diagnostic accuracy was improved by using ADC parameters and was significant, with the 25th and 50th percentiles of ADC for 16-month OS (P = .040 and P = .047) and the 25th percentile of ADC for 12-month PFS (P = .026). No significant correlation was found between ADC parameters and MGMT status. Conclusion ADC histogram analysis had incremental prognostic value over MGMT promoter methylation status in patients with glioblastoma. (©) RSNA, 2016 Online supplemental material is available for this article.

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.

Increased incidence of open-angle glaucoma among hypertensive patients: an 11-year nationwide retrospective cohort study

Objective: To evaluate the risk of open-angle glaucoma (OAG) among patients with systemic hypertension (HTN). Methods: This retrospective propensity-score–matched cohort study included patients with HTN and a matched comparison cohort from the Korean National Health Insurance Service National Sample Cohort database. The HTN group was defined as patients who were prescribed antihypertensive medication, or SBP at least 140 or DBP at least 90 mmHg. The OAG group was defined as patients satisfying OAG criteria during repeated visits to an ophthalmologist. The Charlson comorbidity index was used to control for systemic conditions. Cox proportional hazard regression analysis was performed. Results: OAG occurred in 2.0% (n = 1961) in the HTN group, and 1.7% (n = 1692) in the comparison group (P < 0.001). The OAG incidence rates in patients with and without HTN were 19.0 and 16.4 per 10 000 person-years, respectively. HTN was associated with increased OAG incidence [adjusted hazard ratio (HR) = 1.16, 95% confidence interval: 1.09−1.24] from our multivariate Cox model. Participants with higher SBP (adjusted HR = 1.12 for 120−139 mmHg group; and adjusted HR = 1.20 for ≥140 mmHg group) was more likely to have subsequent OAG compared with participants with less than 120 mmHg blood pressure. Participants with higher DBP (adjusted HR = 1.11 for 80−89 mmHg group: and adjusted HR = 1.07 for ≥90 mmHg group) showed similar trends as participants with less than 80 mmHg blood pressure. Conclusion: Patients diagnosed with HTN are more likely to experience subsequent OAG than those without HTN.

A nationwide cohort study of cigarette smoking and risk of neovascular age-related macular degeneration in East Asian men

Background Few longitudinal studies have evaluated the relationship between cigarette smoking and risk of neovascular age-related macular degeneration (AMD) among Asian populations. This study aimed to prospectively evaluate the association between cigarette smoking and risk of neovascular AMD among Korean men. Methods Men between the ages of 45 and 79 years included in the Korea National Health Insurance Service database from 2002 through 2013. We compared hazard ratios (HR) for neovascular AMD between 64 560 past/current and 64 560 never smokers by 1:1 propensity-matched analysis and 85 267 past/current and 72 347 never smokers by unmatched cohort and propensity-adjusted analysis. Results The risk of neovascular AMD among past/current smokers was 50% higher than that among never smokers (propensity-adjusted whole cohort analysis: HR, 1.48; 95% CI 1.22 to 1.79; propensity-matched analysis: HR, 1.50; 95% CI 1.22 to 1.84), with the risk more pronounced among current than past smokers (current vs past smokers: propensity-adjusted whole cohort analysis, HR, 1.66; 95% CI 1.35 to 2.04 vs HR, 1.15, 95% CI 0.87 to 1.52; propensity-matched analysis, HR, 1.65; 95% CI 1.32 to 2.05 vs HR, 1.21; 95% CI 0.90 to 1.63). Duration of smoking and daily cigarette consumption was associated with the incidence of neovascular AMD in a dose-dependent manner (p<0.001 for trend). Conclusions Cigarette smoking is associated with a strong risk of neovascular AMD among Korean men. These data highlight the public health impact of smoking on blindness in Asia.