Minwook Chang

Retinal vessel diameter, retinal nerve fiber layer thickness, and intraocular pressure in Korean patients with normal-tension glaucoma

PURPOSE To investigate the retinal vessel diameter and evaluate the relationship of the retinal nerve fiber layer (RNFL) thickness with retinal vessel diameter and intraocular pressure (IOP) in patients with normal-tension glaucoma (NTG). DESIGN A prospective, cross-sectional study. METHODS This study included 60 previously untreated patients with NTG (60 eyes) and 45 age- and sex-matched healthy controls (45 eyes) that had no history of systemic vascular disease at a single institution. The diameters of the central retinal arteries and veins were measured on retinal photographs. The central retinal arteriolar equivalent (CRAE) and central retinal venular equivalent (CRVE) were calculated using the revised Parr-Hubbard formula. The RNFL thickness was measured using Stratus optical coherence tomography. RESULTS The mean central retinal arteriolar (P = .000) and venular (P = .000) diameters were significantly smaller in the eyes with NTG than in the normal eyes. Multivariate linear regression analysis demonstrated a significant positive correlation between the RNFL thickness and CRAE (P = .014), and a negative correlation between the RNFL thickness and IOP (P = .005) in the eyes with NTG. However, there was no significant correlation between the RNFL thickness and the independent variables in the control group (P = .112). CONCLUSION The patients with NTG had smaller diameters of the central retinal vessels than the normal subjects. Both IOP and CRAE were significantly associated with RNFL thickness in the patients with NTG. Our results suggest that narrower retinal vessels and higher IOP may be related to the thinning of the RNFL in patients with NTG.

Robust superhydrophobic carbon nanofiber network inlay-gated mesh for water-in-oil emulsion separation with high flux

Much progress has been made toward applying super-wetting membranes to various oil–water separation processes with high molecular permeation flux. However, there are still numerous challenges in the simple preparation of extremely durable membranes with super-wetting properties, especially considering the great developments in high-flux membranes with nanometer-scale thickness. Previous membranes have been usually limited to either high durability with low selectivity or enhanced separation performance with low stability. Herein, an extremely robust carbon nanofiber-polydimethylsiloxane (CNFs-PDMS) network inlay-gated stainless steel mesh (SSM) that shows superhydrophobic and superoleophilic properties is presented. Carbon nanofibers are subtly deposited into SSM pores to form network fillers via an improved vacuum-based filtration. Most importantly, the SSM/CNFs-PDMS membrane exhibits excellent resistance to harsh environmental conditions such as acid, salt, organic, biofouling, and mechanical abrasion. In particular, mechanical damage to the inserted membrane can be avoided using the protective SSM, thereby ensuring super-wetting performance. In the present work, we propose a new concept of discrete or partial superhydrophobicity. Moreover, compared to previous superhydrophobic membranes, the thickness is significantly decreased, leading to enhanced oil-in-water emulsion separation flux. The membranes exhibit a gravity-driven water-in-oil emulsion separation with flux up to 2970 L m−2 h−1. This work provides a brand new route for designing durable and high-flux separation systems with an inlay-gated structure in the future by combining ultrathin membranes with protective supports.

The Effect of Silica Nanoparticles on Human Corneal Epithelial Cells.

Ocular drug delivery is an interesting field in current research. Silica nanoparticles (SiNPs) are promising drug carriers for ophthalmic drug delivery. However, little is known about the toxicity of SiNPs on ocular surface cells such as human corneal epithelial cells (HCECs). In this study, we evaluated the cytotoxicity induced by 50, 100 and 150 nm sizes of SiNPs on cultured HCECs for up to 48 hours. SiNPs were up-taken by HCECs inside cytoplasmic vacuoles. Cellular reactive oxygen species generation was mildly elevated, dose dependently, with SiNPs, but no significant decrease of cellular viability was observed up to concentrations of 100 μg/ml for three different sized SiNPs. Western blot assays revealed that both cellular autophagy and mammalian target of rapamycin (mTOR) pathways were activated with the addition of SiNPs. Our findings suggested that 50, 100 and 150 nm sized SiNPs did not induce significant cytotoxicity in cultured HCECs.

Analysis of lid contour change with aging in asians by measuring midpupil lid distance

Background: The purpose of this study was to analyze the upper eyelid contour of normal adults and differences of these contour according to sex and age in Asians using a software program that measures multiple radial midpupil lid distance. Methods: Conventional and 12 oblique midpupil lid distances every 15 degrees across the temporal (105, 120, 135, 150, 165, and 180 degrees) and nasal (75, 60, 45, 30, 15, and 0 degrees) fields of the lid fissure of 360 healthy Korean subjects older than 20 years and younger than 80 years in both sexes (30 subjects in each group) were measured using custom software. Midpupil lid distances and angles of the medial and lateral canthal ends were also analyzed, and the palpebral fissure inclination was measured. Results: Midpupil lid distances decreased in all angles with advancing age. When midpupil lid distances at the same angles were compared, the mean differences between those in their 20s, 60s, and 70s at 0° and 180° were statistically significant in males (p = 0.039 and 0.045, respectively). In women, the mean differences in all directions between participants in their 20s and those in their 60s and 70s were statistically significant (p < 0.05). Conclusions: Normal eyelid contour in Asians was the shape of an arch that has higher temporal lid contour than the nasal one. There were remarkable decreases in midpupil lid distances in the temporal sectors of the lid fissure with aging, especially at the lateral canthal end. Consideration of the normal shapes and parameters of eyelid contour may improve preoperative planning in aesthetic and reconstruction procedures of the eyelid to restore youthful eyelids.

Computed tomographic dimensions of the lacrimal gland in healthy orbits.

PurposeThe aims of this study were to evaluate the normal range of the dimensions of lacrimal glands in the healthy orbits of Korean subjects and to evaluate their association with clinical findings. MethodsA retrospective survey of patients who had visited the Korea University Medical Center and had undergone orbital computed tomographic scan was performed. One hundred eighty Korean patients (90 men and 90 women) who were older than 20 years and without orbital disease were included. Patients with trauma to the orbits or any known lacrimal gland disease were excluded. The length and width of the lacrimal gland were measured in axial and coronal sections using the largest image. The primary outcome was a descriptive analysis of the distribution of dimensions in normal orbits. We analyzed the results and identified associations with age, sex, and laterality and compared our results with a previous study on normal white lacrimal gland dimensions. ResultsThe mean lacrimal gland axial length was 14.9 mm in the right orbit and 14.7 mm in left orbit. Coronal lengths averaged 20.9 mm in the right orbit and 20.7 mm in the left orbit. The axial width was 4.1 mm in the right orbit and 4.3 mm in the left orbit. The coronal width averaged 3.6 mm in the right orbit and 3.8 mm in the left orbit. A significant inverse linear relationship was observed in both orbits between gland size and age in all dimensions, with the exception of axial width. ConclusionsThis study presents a normal range of Korean lacrimal gland dimensions as measured by computed tomography. This range can aid in differentiating diseased and nondiseased lacrimal glands, especially when used in combination with physical examination. These data may also be useful in clinical trials that involve lacrimal gland size.

Surgical correction for lower lid epiblepharon using thermal contraction of the tarsus and lower lid retractor without lash rotating sutures

Purpose To evaluate the long-term efficacy of a new surgical technique for the correction of lower lid epiblepharon using thermal contraction of the tarsus and lower lid retractor without lash rotating sutures. Methods A retrospective study was conducted on 112 eyes of 56 patients who underwent surgical correction of lower lid epiblepharon with a modified Hotz operation (group A) or a new procedure (group B). The new technique requires that thermal contraction using bipolar cautery was applied to the inferior tarsus including the pretarsal orbicularis oculi muscle and lower lid retractor to create lash rotation without additional rotating sutures. The authors compared the results from these two techniques. Results 44 eyes of 22 patients (11 boys and 11 girls) were included in group A, the average age was 5.5 years (±2.2), follow-up periods were 56.9 months (±7.7). Undercorrections developed in four eyes (9.1%), and epiblepharon recurred in seven eyes (15.9%). In group B, 68 eyes of 34 (20 male and 14 female) patients were included, with an average age of 5.1 years (±2.5), and a mean follow-up period of 39.7 months (±9.5). Epiblepharon recurred in three eyes (4.4%), and no patients were undercorrected. The recurrence and undercorrection rates were significantly lower in group B (p=0.022 and p=0.047). Conclusion The new surgical technique for the correction of lower lid epiblepharon using thermal contraction of the tarsus and lower lid retractor without lash rotating sutures was very useful and effective for the correction of epiblepharon, with good cosmetic results.

Association of Facial Asymmetry and Nasal Septal Deviation in Acquired Nasolacrimal Duct Obstruction in East Asians

Purpose The objective of this study was to evaluate the association of facial asymmetry and nasal septal deviation in acquired unilateral nasolacrimal duct (NLD) obstruction. Methods A retrospective survey was conducted of 39 patients (6 male and 33 female) who had undergone endoscopic dacryocystorhinostomy at the Korea University Ansan Hospital. Patients with trauma to the orbit or any known lacrimal duct disease were excluded. The primary goal was to obtain a descriptive analysis of facial asymmetry and nasal septal deviation. We analyzed the results and identified associations with facial asymmetry and nasal septal deviation in NLD obstruction and determined the influence of the degree of asymmetry and deviation on the results. Results The mean length of the straight line drawn from the lateral canthus to the corner of the mouth was 10.2 cm in the right eye and 9.9 cm in the left eye, and the difference was statistically significant by the Wilcoxon signed rank test (P = 0.043). The laterality of NLD obstruction corresponded to the smaller side of the face in 27 of 39 patients (P = 0.038, &kgr; = 0.753 by cross-table McNemar test). Also, a significant positive linear relation of correspondence of NLD obstruction to the smaller side of the face was observed according to the degree of facial asymmetry (P = 0.043 by linear-by-linear association). Nasolacrimal duct obstruction appeared to occur on the side in which the nasal septum was deviated in 25 of 39 patients (P = 0.043, &kgr; = 0.652 by cross-table McNemar test). Significant positive linear relation of correspondence of NLD obstruction to the side in which the nasal septum was deviated was also observed according to the degree of nasal septal deviation (P = 0.045 by linear-by-linear association). There is also a trend of nasal septal deviation toward the smaller side of the face (total 25 of 39 patients, P = 0.043 by cross-table McNemar test). Conclusions Unilateral NLD obstruction appears to occur on the side in which the nasal septum is deviated, and nasal septal deviation tends to be toward the smaller side of the face. Also, the degree of facial asymmetry and nasal septal deviation may affect NLD obstruction. This study showed that facial asymmetry and nasal septal deviation could be a cause of unilateral NLD obstruction. This finding can aid in differentiating lacrimal duct obstruction, especially when combined with physical examination.

Effect of Nitric Oxide on Human Corneal Epithelial Cell Viability and Corneal Wound Healing

Although the wound healing effects of nitric oxide (NO) are known, the mechanism by which NO modulates corneal wound healing remains unclear. In this study, we investigated the effect of exogenous NO donor (NaNO2) on corneal wound healing. We found that NaNO2 (0.1 μM to 100 μM) increased human corneal epithelial cell (HCEC) viability and migration. It also modulated the phosphorylation of mitogen-activated protein kinases (MAPKs) in a time- dependent manner in those HCECs. Further, p38 MAPK phosphorylation increased at 6 h and normalized at 24 h, while the phosphorylation of extracellular signal regulated kinase (ERK) was increased both at 6 h and 24 h. Topical treatment with NaNO2 (10 μM) enhanced corneal epithelial healing and decreased corneal opacity in murine corneal alkali burn model by modulating inflammatory cytokines. Our findings suggest that NO increased HCEC proliferation and migration via time-dependent MAPK activation and eventually enhanced corneal recovery from the alkali burn.

The paradoxical predominance of medial wall injuries in blowout fracture

Purpose:To evaluate the type and cause of orbital blowout fractures in Korea. Design:Retrospective, observational case series. Methods:Patients who underwent reconstruction for blowout fracture from March 2004 to April 2013 at Korea University Guro and Ansan Hospitals were included in this study. Patient demographics and orbital computed tomography (CT) scans were reviewed. On CT, ethmoid air cell septa, blowout fracture type, and other combined fractures were analyzed. Blowout fracture was classified as affecting up to 4 areas: the floor lateral to the infraorbital canal, the floor medial to the canal, the maxilla-ethmoidal strut (“inferomedial” strut), and the medial wall. Furthermore, trauma type and associated injury were reviewed. The results of adolescent patients and adult patients were compared, as were those of males and females. Results:The study included 659 eyes of 659 patients; mean patient age was 31.01 ± 14.27 years. In total, 513 (77.85%) patients were male and 146 (22.15%) were female. The most common blowout fracture type was medial wall fracture, followed by floor wall, floor and medial wall without inferomedial strut, and floor and medial wall fracture with inferomedial strut, in that order. Interestingly, patients with floor wall blowout fracture were younger (26.87 ± 12.90 y) than other groups: medial wall fracture (32.35 ± 14.64 y, P < 0.0001), floor and medial wall fracture (35.22 ± 14.49 y, P < 0.0001), and floor and medial wall fracture involving the maxillaethmoidal strut (32.62 ± 13.75 y, P = 0.002). The number of ethmoidal air cell septa was lowest in the medial wall fracture group (3.62 ± 0.67): floor wall fracture (4.07 ± 0.69, P < 0.0001), floor and medial wall fracture (3.90 ± 0.78, P < 0.0001), and floor and medial wall fracture involving the maxilla-ethmoidal strut (4.05 ± 0.72, P = 0.001). Conclusions:Our study demonstrated that the blowout fracture type distribution in Korea varied from the results of many other studies. Medial wall fracture is the most common among the 4 types, and anatomic variance, such as number of ethmoid air cell septa, could influence blowout fracture type, especially in medial wall fracture.

Clinical Characteristics and Effectiveness of the Lateral Tarsal Strip and Medial Spindle Procedure.

AbstractThis study was undertaken to evaluate the clinical characteristics and efficacy of the lateral tarsal strip (TS) and medial spindle procedure (MS). We conducted a retrospective chart review of the patients who underwent TS and MS between September 2008 and July 2011 by a single surgeon (S.H.B.). Data were collected on patient age, sex, laterality, diagnosis, procedures performed simultaneously, follow-up duration, postoperative complications, and surgical outcomes. One hundred eleven eyelids of 74 patients who underwent TS and 41 eyelids of 29 patients who underwent MS were included in this study. Patients’ mean age was 61.5 years (range, 24–82) in the TS group and 68.2 years (range, 45–89) in the MS group. The most common diagnoses were lower lid laxity (54.1%) and involutional entropion (26.1%) in the TS group, and punctal ectropion in the MS group (95.1%). The percentage of patients who underwent an additional simultaneous procedure was 86.5% of the TS group and 92.7% of the MS group. Endoscopic dacryocystorhinostomy was the most commonly performed simultaneous procedure in both TS and MS groups (28.1% and 65.8%, respectively). Success rates were 96.4% in the TS group and 97.6% in the MS group. In the TS group, 3 eyelids (2.7%) required reoperation. The most common complication was chemosis in both TS and MS groups (51.4% and 50%, respectively). TS and MS are commonly performed simultaneously with other surgical procedures. These procedures aim to resolve lower lid laxity and punctal ectropion as well as relieve the symptoms of epiphora by stabilizing medial and lateral lid laxity. This review of the clinical features and effectiveness of MS and TS procedures provides useful information for clinicians.