PurposeTo investigate the prevalence and risk factors for an epiretinal membrane (ERM) in Korean population.MethodsUsing the database of the Korea National Health and Nutrition Examination Survey from 2008 through 2012, 14,772 participants 40 years of age or older with gradable fundus photographs were included. The presence of ERM was determined by using fundus photographs. The prevalence of ERM was estimated and possible risk factors including systemic factors, nutritional status, and blood tests were analyzed via multiple logistic regression analyses.ResultsThe prevalence of ERM was 2.9% (95% confidence interval [CI], 2.6% to 3.3%). On multiple logistic regression analysis, the prevalence of ERM was affected by age. The odds ratios (ORs) against the forties were 2.70, 5.48, and 5.69 in the fifties, sixties, and seventies, respectively. ERM was also significantly affected by cataract surgery (OR, 2.82; 95% CI, 2.08 to 3.81) and by the increase in intake of 100-mg calcium (OR, 1.05; 95% CI, 1.00 to 1.11). ERM had negative associations with red blood cell count (OR, 0.66; 95% CI, 0.45 to 0.95).ConclusionsThe estimated nation-wide prevalence of ERM in Korea is 2.9%. The presence of ERM in the general population is associated with age, cataract surgery, increased dietary calcium, and a low red blood cell count.

The introduction of inorganic nanoparticles into carbon nanotube (CNT) papers can provide a versatile route to the fabrication of CNT papers with diverse functionalities, but it may lead to a reduction in their mechanical properties. Here, we describe a simple and effective strategy for the fabrication of mechanically robust magnetic CNT papers for electromagnetic interference (EMI) shielding and magnetomechanical actuation applications. The magnetic CNT papers were produced by vacuum filtration of an aqueous suspension of CNTs, CoFeO nanoparticles, and poly(vinyl alcohol) (PVA). PVA plays a critical role in enhancing the mechanical strength of CNT papers. The magnetic CNT papers containing 73 wt % of CoFeO nanoparticles exhibited high mechanical properties with Young's modulus of 3.2 GPa and tensile strength of 30.0 MPa. This magnetic CNT paper was successfully demonstrated as EMI shielding paper with shielding effectiveness of ∼30 dB (99.9%) in 0.5-1.0 GHz, and also as a magnetomechanical actuator in an audible frequency range from 200 to 20 000 Hz.

PurposeThe purpose was to investigate precursor lesions of polypoidal choroidal vasculopathy (PCV).MethodsThis cross-sectional study involved 276 unaffected contralateral eyes from unilateral PCV patients (Group 1), unilateral typical exudative age-related macular degeneration (AMD) patients (Group 2), and unilateral epiretinal membrane patients (Group 3) as age-matched controls. Grayish-yellow sub-retinal or sub-retinal-pigment-epithelial deposits larger than 63 μm in size with irregular but discrete margins were defined as drusen-like deposits (DLDs). The frequencies of DLDs, drusen, and pigmentary changes in each group were compared.ResultsDLDs larger than 125 μm in size were found more frequently in Group 1 (19.5 %) than in Groups 2 (3.4 %) and 3 (3.2 %) (p < 0.001). Soft drusen were discovered more frequently in Group 2 eyes than in Groups 1 and 3 (p < 0.001). Pigmentary changes were found more frequently in Groups 1 and 2 compared to Group 3. Compared with the other groups, Group 1 manifested a higher frequency of choroidal vascular hyperpermeability (p < 0.005) and thicker choroid (p < 0.001).ConclusionsThe precursor lesions of PCV are different from those of exudative AMD. DLDs larger than 125 μm and pigmentary changes may be early preclinical markers of PCV. Long-term longitudinal studies are warranted for validation.

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We investigated morphologic features of choroid in the choroidal thickening diseases, including central serous chorioretinopathy (CSC), polypoidal choroidal vasculopathy (PCV), and Vogt-Koyanagi-Harada disease (VKH), by a novel tomographic classification system of the choroid. This cross-sectional study involved 30 patients with active CSC, 30 patients with active PCV, and 27 patients with active VKH, and 30 normal controls. Utilizing enhanced depth imaging optical coherence tomography, we classified the morphology of the choroid into five categories: 1) Standard (S), 2) Dilated outer layer and Attenuated inner layer (DA), 3) Darkened (D), 4) Marbled (M), and 5) Pauci-Vascular (PV) types. Additional tomographic characteristics of the choroid such as choroidal vascular dilation, convolution, scleral invisibility, and choroidal hyper- or hypo-thickening were identified as well. The distribution of five choroidal tomographic morphology and additional tomographic characteristics in each group were analyzed. The DA type was observed in the CSC group more frequently than in the normal control group (53.3% vs 3.3%, P < 0.001). Additional tomographic characteristics, such as choroidal vascular dilation (76.7%), and choroidal hyper-thickening (36.7%), were more prevalent in the CSC group than in the control group. The PCV group showed higher prevalence of DA type (33.3% vs. 3.3%, P = 0.006) than the control group. The VKH group showed a significantly higher frequency of the D type (63.0%), convolution (40.7%), and scleral invisibility (70.4%) than controls (0% for all three findings). In conclusion, CSC and PCV shared common morphologic characteristics of choroid, including dilated outer vascular layer and focally attenuated innermost layer. Dense hypo-reflectivity and convolution of choroid were the specific tomographic markers for acute VKH. A new tomographic classification system of choroid may provide discrimination ability and insight into major pachychoroidopathies.

Although High Efficiency Video Coding (HEVC) is suitable for high definition (HD) and ultra-HD video services due to its high compression efficiency and excellent coded picture quality, its high encoding complexity is an obstacle for wide-spread practical applications. Although many fast coding schemes can alleviate the complexity problem, their coding quality suffers much. In this paper, an early skip mode decision is proposed to reduce the encoding complexity of HEVC while not sacrificing its coding quality much. The proposed method determines the skip mode by utilizing its distortion characteristics just after calculating rate-distortion cost of 2N×2N merge mode, and those prediction units decided as the skip mode do not undergo remaining mode decision processes. The threshold for the early decision is estimated directly from the video data themselves. Experimental results show that the proposed method achieves encoding complexity reduction of 30.1% in random access main condition and 26.4% in low-delay main condition on average with virtually no coding loss compared to the HEVC full rate-distortion optimized decision.Index Terms-High Efficiency Video Coding (HEVC), skip, fast encoding, low complexity.

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