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Lee H.,Yonsei University | Lee K.,Yonsei University | Ahn J.M.,Yonsei University | Kim E.K.,Yonsei University | And 3 more authors.
Optometry and Vision Science | Year: 2014

PURPOSE: To compare the optical quality measurements obtained from the double-pass system and ocular aberrations, subjective visual acuity, and contrast sensitivity score in pseudophakic eyes. Methods: Three months after cataract surgery, modulation transfer function (MTF) cutoff frequency, Strehl ratio, objective scatter index, and objective pseudoaccommodation obtained from the double-pass system were compared with total aberration, higher-order aberration, and spherical aberration obtained from ray-tracing aberrometer. In addition, parameters of the double-pass system were compared with subjective visual acuity and the contrast sensitivity score. RESULTS: Forty eyes of 40 patients were included. The MTF cutoff frequency and Strehl ratio were negatively correlated with total aberration (r = -0.503, p = 0.003; r = -0.509, p = 0.003, respectively) and subjective visual acuity (r = -0.453, p = 0.007; r = -0.354, p = 0.040, respectively). The objective scatter index was positively correlated with total aberration (r = 0.451, p = 0.024) and subjective visual acuity (r = 0.516, p = 0.008). The MTF cutoff frequency showed a correlation with contrast sensitivity score under photopic and mesopic conditions. CONCLUSIONS: Optical quality parameters obtained from the double-pass system were correlated with ocular aberrations, subjective visual acuity, and contrast sensitivity score in pseudophakic eyes. Copyright © 2014 American Academy of Optometry. Source

Han K.E.,Corneal Dystrophy Research Institute | Han K.E.,Institute of Vision Research | Kim C.Y.,Institute of Vision Research | Chung J.L.,Konyang University | And 6 more authors.
Journal of Cataract and Refractive Surgery | Year: 2012

A 57-year-old woman had concomitant surgery of persistent pupillary membrane removal and uneventful phacoemulsification through the same temporal clear corneal incision in her left eye. Short axial lengths (right eye, 21.08 mm; left eye, 20.39 mm) with shallow angles were noted bilaterally, and other findings were not remarkable. The patient experienced angle-closure attacks 3 and 7 months postoperatively. At the second angle-closure attack, diffuse epithelial ingrowth was observed. The epithelial ingrowth covered the intraocular lens surface in the interpupillary area, the iris surface surrounding the pupil, and the temporal anterior chamber angle, but did not reach the corneal endothelial incision. After observation of iris blanching with laser photocoagulation, argon laser photocoagulation was applied to the epithelium covering the iris and angle 7 times during the following month. The epithelial ingrowth was completely removed and did not recur during the 36-month follow-up. Financial Disclosure: No author has a financial or proprietary interest in any material or method mentioned. © 2012 ASCRS and ESCRS. Source

Maeng Y.-S.,Corneal Dystrophy Research Institute | Maeng Y.-S.,Yonsei University | Kwon J.Y.,Yonsei University | Kim E.K.,Corneal Dystrophy Research Institute | And 2 more authors.
Stem Cells | Year: 2015

As the ability to control the differentiation of endothelial stem/progenitor cells (EPCs) into vascular endothelial cell lineages could be useful for promoting neovascularization, it is important to obtain a deeper understanding of the epigenetic mechanisms that regulate EPC differentiation and neovascularization. Heterochromatin protein 1α (HP1α) is known to be involved in the epigenetic regulation of gene silencing. However, recent reports demonstrate that HP1α can also activate gene expression during cell differentiation. In this study, microarray analysis revealed that HP1α expression was induced during EPC differentiation and is associated with the expression of outgrowing endothelial cell (OEC)-specific protein markers. To explore the role of HP1α in the differentiation of EPCs to OECs, its expression was knocked-down or over-expressed in differentiating EPCs. Overexpression of HP1α promoted the differentiation and angiogenic activity of EPCs in vitro and in vivo, whereas knockdown of HP1α led to a defect in OEC migration, tube formation, and angiogenic sprouting activity. Gene expression profiling showed increased expression of angiogenic genes, including NOTCH1, cadherin-5, and angiopoietin-like-2, and decreased expression of progenitor cell marker genes, including CD133, CXCR4, and C-KIT, in HP1α-overexpressing EPCs. Also, increased HP1α at an early stage of EPC differentiation may regulate angiogenic gene transcription by interacting with chromatin that modifies epigenetic factors such as the methyl-CpG binding domain, Polycomb group ring finger 2, and DNA methyltransferases. Our findings demonstrate, for the first time, that HP1α plays an important role in the differentiation and angiogenic function of EPCs by regulating endothelial gene expression. Stem Cells 2015;33:1512-1522 © 2015 AlphaMed Press. Source

Jung J.W.,Corneal Dystrophy Research Institute | Kwon K.Y.,Corneal Dystrophy Research Institute | Choi D.L.,Washington University in St. Louis | Kim T.-I.,Corneal Dystrophy Research Institute | And 3 more authors.
Cornea | Year: 2015

Purpose: The aim of this study was to investigate long-term clinical outcomes of conjunctival flap surgery for calcified scleromalacia after periocular surgery. Methods: We examined 73 surgical sites (nasal and/or temporal area) in 60 eyes from 43 patients who underwent conjunctival flap surgery for calcified scleromalacia arising from cosmetic wide conjunctivectomy or pterygium excision. Clinical outcomes, including the need for reoperation and development of complications, were evaluated over a long-term follow-up period. Morphological evaluations of the surgical area at final follow-up were performed using a total score for injection severity, ocular surface smoothness, and choroid visibility, and patients subjectively evaluated their cosmetic outcome using a scale of 0 (very poor) to 4 (excellent). Results: The mean follow-up duration after final conjunctival flap surgery was 26.5 ± 6.8 months (range, 15-52 months). There were no cases of progressive scleral thinning or serious complications such as flap necrosis or scleral perforation. Only 3 surgical areas with an inferior flap required additional flap placement because of avascular sclera exposure. Minor complications such as conjunctival cyst, edematous flap, vessel engorgement, and flap hypertrophy were easily treated or spontaneously improved. Mean morphological score was 2.2 and cosmetic outcome score was 2.9, indicating almost "good" outcomes. Conclusions: Based on our long-term experience, we propose that conjunctival flap surgery may be a safe and satisfactory treatment for complicated calcified scleromalacia after periocular surgery. Copyright © 2014 Wolters Kluwer Health, Inc. All rights reserved. Source

Ha B.J.,Siloam Eye Hospital | Kim T.-I.,Corneal Dystrophy Research Institute | Kim T.-I.,Yonsei University | Choi S.-I.,Corneal Dystrophy Research Institute | And 6 more authors.
Cornea | Year: 2010

Purpose: To evaluate the effect of mitomycin C (MMC) on the exacerbation of corneal opacity that occurs in patients with granular corneal dystrophy type II (GCD II) after refractive corneal surface ablation. Methods: Ten eyes of patients with GCD II who underwent refractive corneal surface ablation with MMC were compared with 10 eyes that were not treated with MMC. Best spectacle-corrected visual acuity, the degree of corneal opacity, and contrast sensitivity were evaluated at least 3 years after surgery. Corneal opacities were quantified using Pentacam densitometry maps. Results: No measured between-group value showed a statistically significant difference. Conclusion: Simultaneous application of MMC does not prevent exacerbation of GCD II after refractive corneal surface ablation. Copyright © 2010 by Lippincott Williams & Wilkins. Source

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