Manufacturing and Characterization of Dental Crowns Made of 5-mol% Yttria Stabilized Zirconia by Digital Light Processing.

We herein report manufacturing of dental crowns made of 5-mol% yttria partially stabilized zirconia (5Y-PSZ) with desired mechanical properties, optical translucency and dimensional accuracy using digital light processing (DLP). To this end, all processing parameters were carefully controlled and optimized. First, 5Y-PSZ particles with a bimodal distribution were prepared via calcination of as-received granules and subsequent ball-milling and then used to formulate 5Y-PSZ suspensions with a high solid loading of 50 vol% required for high densification after sintering. Dispersant content was also optimized. To provide high dimensional accuracy, initial dimensions of dental crowns for 3D printing were precisely determined by considering increase and decrease in dimensions during photopolymerization and sintering, respectively. Photopolymerization time was also optimized for a given layer thickness of 50 µm to ensure good bonding between layers. A multi-step debinding schedule with a slow heating rate was employed to avoid formation of any defects. After sintering at 1500 °C for 2 h, 5Y-PSZ could be almost fully densified without noticeable defects within layers and at interfaces between layers. They had high relative densities (99.03 ± 0.39%) with a high cubic phase content (59.1%). These characteristics allowed for achievement of reasonably high mechanical properties (flexural strength = 625.4 ± 75.5 MPa and Weibull modulus = 7.9) and % transmittance (31.4 ± 0.7%). In addition, 5Y-PSZ dental crowns showed excellent dimensional accuracy (root mean square (RMS) for marginal discrepancy = 44.4 ± 10.8 µm and RMS for internal gap = 22.8 ± 1.6 µm) evaluated by the 3D scanning technique.

The Role of Nuclear Factor of Activated T Cells 5 in Hyperosmotic Stress-Exposed Human Lens Epithelial Cells.

We investigated the role of nuclear factor of activated T cells 5 (NFAT5) under hyperosmotic conditions in human lens epithelial cells (HLECs). Hyperosmotic stress decreased the viability of human lens epithelial B-3 cells and significantly increased NFAT5 expression. Hyperosmotic stress-induced cell death occurred to a greater extent in NFAT5-knockout (KO) cells than in NFAT5 wild-type (NFAT5 WT) cells. Bcl-2 and Bcl-xl expression was down-regulated in NFAT5 WT cells and NFAT5 KO cells under hyperosmotic stress. Pre-treatment with a necroptosis inhibitor (necrostatin-1) significantly blocked hyperosmotic stress-induced death of NFAT5 KO cells, but not of NFAT5 WT cells. The phosphorylation levels of receptor-interacting protein kinase 1 (RIP1) and RIP3, which indicate the occurrence of necroptosis, were up-regulated in NFAT5 KO cells, suggesting that death of these cells is predominantly related to the necroptosis pathway. This finding is the first to report that necroptosis occurs when lens epithelial cells are exposed to hyperosmolar conditions, and that NFAT5 is involved in this process.

Clinical characteristics and prognostic factors in hypertensive anterior uveitis diagnosed with polymerase chain reaction.

Aim of the study is to report the clinical characteristics and prognostic factors in hypertensive anterior uveitis (AU) diagnosed with multiplex polymerase chain reaction (PCR). Eighty-eight eyes of 88 patients with hypertensive AU were enrolled from 2015 to 2019 in a tertiary center in South Korea. All patients underwent multiplex PCR that was performed using aqueous humor samples collected at first visit to detect the DNA of six herpesviruses. Twenty-eight (31.8%) eyes were PCR positive. Herpes simplex virus was found in 6 (6.8%) eyes, varicella-zoster virus in 7 (8.0%) eyes, cytomegalovirus in 14 (15.9%) eyes, and Epstein-Barr virus in 1 (1.1%) eye. On multivariate regression analysis, PCR positivity was significantly associated with coin-shaped keratic precipitates (odds ratio (OR) = 6.01, P = 0.044). Recurrence and final visual acuity were significantly associated with a presumed diagnosis of viral endotheliitis (OR = 21.69, P = 0.04 and OR = 6.3, P = 0.004, respectively). This study showed the importance of PCR positivity, suggesting that identification of the virus through active PCR testing could affect the course, treatment, and prognosis of hypertensive AU.

Comparison of Lamina Cribrosa Morphology in Normal Tension Glaucoma and Autosomal-Dominant Optic Atrophy.

Purpose: To compare lamina cribrosa (LC) morphology in patients with normal tension glaucoma (NTG) and autosomal-dominant optic atrophy (ADOA). Methods: This cross-sectional study matched 24 patients diagnosed with ADOA (24 eyes) by age and retinal nerve fiber layer thickness with 48 patients diagnosed with NTG (48 eyes) by age with 48 healthy controls (48 eyes). Optic nerve heads were scanned by enhanced-depth imaging (EDI) optical coherence tomography (OCT). The LC curvature index (LCCI) and LC depth (LCD) on B-scan images obtained using EDI-OCT were measured at seven locations spaced equidistantly across the vertical optic disc diameter and compared among the NTG, ADOA, and control groups. Results: Mean LCCI and LCD were significantly greater in NTG than in ADOA and healthy eyes (P < 0.001 each) but did not differ significantly in ADOA and healthy eyes. Conclusions: NTG eyes have a more posteriorly curved and deeper LC than ADOA and healthy eyes. This finding provides insight into the role of LC morphology in NTG and provides a clinical clue to distinguish between NTG and ADOA.

Parapapillary choroidal microvasculature dropout in nonglaucomatous healthy eyes.

PURPOSE: To determine the incidence of parapapillary choroidal microvasculature dropout (MvD) in nonglaucomatous healthy eyes using optical coherence tomography angiography (OCTA) and to characterize the MvD observed in these eyes. METHODS: Seventy-six eyes (19 eyes with an MvD and 57 age-matched eyes without an MvD) from a cohort of 297 nonglaucomatous healthy eyes that underwent OCTA were included. The peripapillary choroidal microvasculature was evaluated in en-face images obtained using swept-source OCTA. An MvD was defined as a focal sectoral capillary dropout with no visible microvascular network identified in the en-face images of the choroidal layer. The incidence of MvD and clinical characteristics associated with the presence of an MvD was determined. RESULTS: MvD was found in 19 of the 297 nonglaucomatous healthy eyes (6.4%). Compared with age-matched eyes without an MvD, eyes with an MvD had lower systolic blood pressure (p = 0.021), diastolic blood pressure (p = 0.048), mean arterial pressure (p = 0.025) and mean ocular perfusion pressure (p = 0.032). Logistic regression analyses showed that cold extremities (p = 0.046), lower mean arterial pressure (p = 0.021) and lower mean ocular perfusion pressure (p = 0.023) were associated with the presence of an MvD. CONCLUSIONS: Parapapillary choroidal MvD can be present in nonglaucomatous healthy eyes. The presence of an MvD is associated with systemic vascular dysregulation.

Microstructure of Nonjuxtapapillary Microvasculature Dropout in Healthy Myopic Eyes.

Purpose: The purpose of this study was to characterize the microstructure of the nonjuxtapapillary microvasculature dropout (MvD) in healthy myopic eyes. Methods: This cross-sectional study included 50 eyes (25 eyes with a nonjuxtapapillary MvD and 25 age-matched eyes without any MvD) from a cohort of 126 nonglaucomatous healthy myopic eyes having parapapillary atrophy (PPA) γ-zone. The parapapillary deep-layer microvasculature was evaluated in en-face images obtained using swept-source optical coherence tomography (OCT) angiography (OCTA). A nonjuxtapapillary MvD was defined as an area with focal absence of vascular signals in the distal portion of PPA confined to the nonjuxtapapillary area. Enhanced depth-imaging OCT scanning was performed to assess the parapapillary microstructure. Results: Nonjuxtapapillary MvD was found in 25 eyes (19.8%). The parapapillary microstructure at the nonjuxtapapillary MvD in 18 eyes was characterized by the misalignment of Bruch's membrane (BM)-retinal pigment epithelium (RPE) complex, which was identified by the absence of BM-RPE complex and the presence of the inner retina and sclera. In seven eyes with a nonjuxtapapillary MvD but without such misaligned BM-RPE complex, RPE atrophy was observed at the location of the nonjuxtapapillary MvD. Eyes with a nonjuxtapapillary MvD had a longer axial length (AXL; P = 0.013) and a wider γ-zone (P < 0.001) than age-matched control eyes without any MvD. Conclusions: The microstructure at the nonjuxtapapillary MvD in healthy myopic eyes was characterized in approximately 70% of eyes by temporally misaligned BM-RPE complex. Although the clinical importance of the nonjuxtapapillary MvD remains to be determined, it should be differentiated from the parapapillary choroidal MvD observed in glaucoma.

Factors associated with myopia in Korean children: Korea National Health and nutrition examination survey 2016-2017 (KNHANES VII).

BACKGROUND: To evaluate the prevalence and risk factors associated with myopia and high myopia in children in South Korea. METHODS: A total of 983 children 5-18 years of age who participated in the Korean National Health and Nutrition Examination Survey 2016-2017 (KNHANES VII), a nationwide population-based cross-sectional study, were evaluated. Myopia and high myopia were defined as a spherical equivalent (SE) ≤ - 0.5 diopters (D) and SE ≤ --6.0 D. The association between refractive errors and potential risk factors for myopia was analyzed. RESULTS: The prevalence of myopia and high myopia was 65.4 and 6.9%, respectively. Older age and parental myopia were significantly associated with both myopia and high myopia, while higher body mass index (BMI) was associated with high myopia only. Although the proportion of subjects who spent more time on near work activities (≥4 h/day) was sequentially increased with increased refractive error, this tendency was not statistically significant by multivariable logistic regression. CONCLUSIONS: Korean children had a high prevalence of myopia and high myopia. In this age group, the risk of myopia increased with aging and parental myopia. Higher BMI may be associated with high myopia.

Elucidation of the Strongest Factors Influencing Rapid Retinal Nerve Fiber Layer Thinning in Glaucoma.

Purpose: To determine which groupings of prognostic factors best explain the rapid progressive retinal nerve fiber layer (RNFL) thinning in patients with primary open-angle glaucoma (POAG). Methods: Optic nerves of 111 POAG patients who were followed for at least 2.5 years, during which the RNFL thickness was measured by serial spectral-domain optical coherence tomography (OCT) were included. Eyes were imaged using enhanced depth-imaging spectral-domain OCT and swept-source OCT angiography to determine the lamina cribrosa curvature index (LCCI), and the presence of a choroidal microvasculature dropout (cMvD), respectively. The rate of RNFL thinning was determined by linear regression of serial OCT RNFL thickness measurements. A regression tree model was used to find groupings of factors that best explain the rate of future RNFL thinning. Results: Disc hemorrhage, larger LCCI, and presence of cMvD were associated with faster global RNFL thinning in the multivariate regression analysis. The regression tree analysis revealed three stratified groups based on the rate of RNFL thinning, divided by the LCCI and the presence of cMvD. Eyes with LCCI ≥11.87 had the fastest RNFL thinning (-2.4 ± 0.8 µm/year, mean ± SD). Among eyes with LCCI <11.87, the presence of cMvD was the strongest factor influencing faster RNFL thinning (-1.5 ± 0.8 µm/year). Eyes with LCCI <11.87 and without a cMvD exhibited the slowest RNFL thinning (-0.8 ± 0.9 µm/year). Conclusions: Our regression tree model demonstrated that larger LCCI, and then the presence of cMvD were the first and second strongest prognostic factors for faster progressive RNFL thinning. Further studies may be needed to confirm these findings.

Dynamic Range of the Peripapillary Retinal Vessel Density for Detecting Glaucomatous Visual Field Damage.

PURPOSE: To evaluate the dynamic range of peripapillary retinal vessel density (ppVD) for predicting the severity of visual field (VF) damage in comparison with that of circumpapillary retinal nerve fiber layer thickness (cpRNFLT) in primary open-angle glaucoma (POAG) patients and to determine the severity of VF damage below which progressive VF loss becomes undetectable based on either ppVD or cpRNFLT. DESIGN: Cross-sectional study. PARTICIPANTS: One hundred thirty-three POAG patients having ppVD, cpRNFLT, and VF sensitivity (VFS) measurements evaluated using OCT angiography, spectral-domain OCT, and standard automated perimetry, respectively. METHODS: Correlations between ppVD and VFS (vessel-function) and between cpRNFLT and VFS (structure-function) were assessed using both linear and fractional polynomial (FP) models. Davies' test was used to determine the breakpoints for VFS below which progressive VF loss became undetectable based on ppVD or cpRNFLT. MAIN OUTCOME MEASURES: Comparison of the vessel-function and structure-function correlations, and the VFS breakpoints in each correlation. RESULTS: Both ppVD and cpRNFLT exhibited significant linear correlations with VFS globally. In the temporal-superior, temporal, and temporal-inferior sectors, the correlations were explained better by the FP model than by the linear model for both ppVD (P ≤ 0.009) and cpRNFLT (P ≤ 0.008). The breakpoints for VFS in the vessel-function and structure-function correlations were -8.28 dB and -6.41 dB, respectively, in the temporal-superior sector, -11.83 dB and -8.42 dB, respectively, in the temporal sector, and -7.92 dB and -6.28 dB, respectively, in the temporal-inferior sector. CONCLUSIONS: The sectoral ppVD exhibits curvilinear correlations with VFS and has significant breakpoints below which the VFS decline becomes undetectable. The VFS breakpoints were lower for ppVD than for cpRNFLT, indicating that the dynamic range of ppVD is potentially larger for detecting more advanced VF damage.

Clinical Features of Herpes Simplex Keratitis in a Korean Tertiary Referral Center: Efficacy of Oral Antiviral and Ascorbic Acid on Recurrence.

PURPOSE: To describe the clinical manifestations of herpes simplex keratitis (HSK) in a tertiary referral center in South Korea and to determine whether ascorbic acid treatment prevents recurrence of herpetic epithelial keratitis. METHODS: This retrospective cohort study included all consecutive patients with herpetic keratitis referred to our center from January 2010 to January 2015. Clinical features, ocular complications, and recurrences were recorded. RESULTS: In total, 149 eyes of the 133 patients (72 male and 61 female) were followed for an average of 24.6 ± 13.2 months. Sixteen (12.0%) patients had bilateral HSK. The most frequent HSK subtype was epithelial keratitis (49.7%), which was followed by stromal keratitis (23.5%). Epithelial keratitis was the most likely subtype to recur. Complications occurred in 122 (81.9%) eyes. The most common complication was corneal opacity. Recurrences were observed in 48 (32.2%) eyes. The recurrence rates were lower in the prophylactic oral antiviral agent group (16 / 48 eyes, 33.3% vs. 49 / 101 eyes, 48.5%) and the ascorbic acid treatment group (13 / 48 eyes, 27.1% vs. 81 / 101 eyes, 70.3%) compared with the groups without medications. Univariate logistic regression analysis revealed that both factors significantly reduced the risk of recurrence (acyclovir: odds ratio, 0.25; 95% confidence intervals, 0.12 to 0.51; ascorbic acid: odds ratio, 0.51; 95% confidence intervals, 0.20 to 0.91). CONCLUSIONS: This retrospective study described the clinical findings of HSK in a tertiary referral center in South Korea. Prophylactic oral antiviral agent treatment and oral ascorbic acid administration may lower the risk of recurrence.

Clinical Results and Utility of Herpesviruses Multiplex Polymerase Chain Reaction: Assessment of Aqueous Humor Samples From Patients With Corneal Endotheliitis and High Intraocular Pressure.

PURPOSE: The main purpose of this study was to evaluate herpesvirus infection in patients with corneal endotheliitis and high intraocular pressure (IOP) using multiplex polymerase chain reaction (PCR) in aqueous humor samples. MATERIALS AND METHODS: This was a retrospective, observational study of immunocompetent patients living in South Korea. Eligible subjects had typical corneal endotheliitis with an IOP≥21 mm Hg or required antiglaucoma medication. Multiplex PCR was performed using aqueous humor samples obtained at first visit to detect the DNA of 6 herpesviruses. RESULTS: Forty-two eyes from 42 patients with >6 months' follow-up were analyzed. Of these, 16 were herpesvirus-positive: 3 herpes simplex virus 1, 3 varicella-zoster virus, 9 cytomegalovirus, and 1 Epstein-Barr virus. Eyes with coin-shaped or fine keratic precipitates (kps), high IOP, and a low baseline endothelial cell count were more likely to show a positive result on multiplex PCR. Univariate analysis showed that male sex (P=0.014), a previous history of uveitic glaucoma (P=0.048), and the presence of fine kps (P=0.031) were significantly associated with a positive PCR result. On multivariate analysis, male sex (P=0.010) and a previous history of uveitic glaucoma (P=0.031) showed a significant positive association. CONCLUSIONS: Cytomegalovirus was the most commonly detected herpesvirus in patients with corneal endotheliitis and high IOP. A positive PCR result was seen more frequently in male individuals and patients with fine kps or a history of uveitic glaucoma.

Extensive Submacular Hemorrhage After Trabeculectomy With Mitomycin C.

PURPOSE: We report the occurrence of an extensive submacular hemorrhage after trabeculectomy with mitomycin C in a patient with an occult choroidal neovascular membrane (CNVM). PATIENTS AND METHODS: A 66-year-old man had a 3-year history of primary open-angle glaucoma in the left eye, which had been treated with topical antiglaucoma medication. The patient had age-related macular degeneration with an occult CNVM, for which he had received 5 intravitreal injections of ranibizumab and 5 intravitreal injections of bevacizumab in the left eye over a 3-year period. As intraocular pressure was not under control in the left eye over a 2-month period, trabeculectomy with mitomycin C was performed. RESULTS: On the first postoperative day, intraocular pressure was 8 mm Hg with a well-formed bleb in the left eye. However, extensive subretinal hemorrhage was observed, and the patient underwent pneumatic displacement and pars plana vitrectomy to remove the hemorrhage. After 7 months, extensive subretinal fibrosis was observed and visual acuity was low (hand movement only). CONCLUSIONS: To our knowledge, this is the first report of an extensive submacular hemorrhage after trabeculectomy with mitomycin C in a patient with an occult CNVM.

The effect of 0.02% mitomycin C injection into the hair follicle with radiofrequency ablation in trichiasis patients.

PURPOSE: To investigate the inhibitory effect of 0.02% mitomycin C on eyelash regrowth when injected to the eyelash hair follicle immediately after radiofrequency ablation. METHODS: We prospectively included 21 trichiasis patients from June 2011 to October 2012. Twenty eyes of 14 patients were treated with 0.02% mitomycin C to the hair follicle immediately after radiofrequency ablation in group 1, while radiofrequency ablation only was conducted in ten eyes of seven patients in group 2. Recurrences and complications were evaluated until six months after treatment. RESULTS: One hundred sixteen eyelashes of 20 eyes in group 1 underwent treatment, and 19 (16.4%) eyelashes recurred. Eighty-four eyelashes of ten eyes in group 2 underwent treatment, and 51 (60.7%) eyelashes recurred. No patients developed any complications related to mitomycin C. CONCLUSIONS: Application of 0.02% mitomycin C in conjunction with radiofrequency ablation may help to improve the success rate of radiofrequency ablation treatment in trichiasis patients.

A novel forkhead box C1 gene mutation in a Korean family with Axenfeld-Rieger syndrome.

PURPOSE: To report a case series of patients with novel forkhead box CI (FOXC1) mutations in a Korean family with Axenfeld-Rieger syndrome (ARS). METHODS: Four members of the same family underwent complete ophthalmologic and systemic examinations and genetic analysis. Genomic DNA was isolated from peripheral blood leukocytes, and all coding exons with flanking intronic regions of the FOXC1 and pituitary homeobox 2 genes were amplified using PCR, and sequenced. RESULTS: The patients were 40, 12, 11, and 10 years old (father, son, and two sisters, respectively). All four had uncontrolled intraocular pressure, glaucomatous visual field defect, retinal nerve fiber layer defect, iridocorneal adhesion on gonioscopy, hypoplasia and marked atrophy of the iris, flattening of the midface, and broad flat noses. A diagnosis of ARS was made based on characteristic ocular and systemic traits. A novel FOXC mutation, c.317delA, was identified in all affected members of the family with ARS. CONCLUSIONS: We found a novel c.317delA mutation in FOXC1 in a Korean family with ARS. We suggest that this FOXC1 mutation causes typical ARS, and that our results may be useful for better understanding of the spectrum of FOXC1 mutations and the role of FOXC1 in the development and progression of ARS.

Effect of Dorzolamide/Timolol or Brinzolamide/Timolol prophylaxis on intravitreal anti-VEGF injection-induced intraocular hypertension.

PURPOSE: To evaluate prospectively whether anti-glaucomatic drugs administered prior to intravitreal anti-vascular endothelial growth factor (VEGF) injection bevacizumab (Avastin,® Roche) or ranibizumab (Lucentis,® Novartis) prevents intraocular hypertension after the injection. SUBJECTS AND METHODS: In total, 166 patients (175 eyes) scheduled for intravitreal anti-VEGF injection treatment were prophylactically treated 1 hour before the procedure with Dorzolamide/Timolol (Cosopt,® MSD) (Group 1, 53 eyes) or Brinzolamide/Timolol (Elazop,® Alcon) (Group 2, 84 eyes) or left untreated (Group 3, 29 eyes). Intraocular pressure was analyzed 5 minutes prior to the injection, every 5 minutes for 30 minutes after the procedure, and 1 hour, 1 day, 7 days, and 1 month after the procedure. RESULTS: The intraocular pressures 5 minutes before the procedure (baseline) for Groups 1, 2, and 3 were 12.06 ± 1.85, 13.98 ± 2.68, and 13.81 ± 2.24 mmHg, respectively. Five and 30 minutes after the procedure, the intraocular pressures of the three groups were 14.12 ± 4.18, 14.87 ± 3.35, and 28.21 ± 3.16 mmHg, respectively, and 10.87 ± 1.58, 14.25 ± 2.43, and 17.48 ± 2.34 mmHg, respectively. For all three groups, the changes relative to baseline 5 and 30 minutes after injection were significant. When the three groups were divided according to whether they received bevacizumab or ranibizumab and the changes in intraocular pressure relative to baseline were analyzed, all six subgroups exhibited significant changes in intraocular pressure 5 and 30 minutes after the procedure. CONCLUSION: The prophylactic administration of anti-glaucomatic drugs prior to intravitreal anti-VEGF injection effectively reduced the early intraocular pressure elevation. This approach was also safe and could be performed accurately.

A Case of Invasive Aspergillosis Presenting as Acute Angle Closure Glaucoma.

Purpose: To report a case of invasive aspergillosis presenting as acute angle closure glaucoma. Case: A 72-year-old male patient visited our clinic with decreased visual acuity and ocular pain on the right eye lasting for 3 d. His intraocular pressure was 42 mmHg in the right eye and 18 mmHg in the left eye. And, there was about 2 mm of exophthalmos, slight ptosis with decreased motility in all directions, conjunctival injection, moderate mydriasis with a relative afferent pupillary defect, and angle closure in the right eye. Orbital computed tomography and magenetic resonance imaging showed isotense mass involving right orbit and ethmoid sinus. Based on the biopsy, invasive aspergillosis was definitely diagnosed. Despite perfoming peripheral laser iridotomy and administrating antifungal agent and antiglaucoma medication, the patient was blinded in his right eye. During the follow-up period, visual acuity in the left eye suddenly decreased due to the invasive aspergillosis in the left paranasal sinus and optic nerve, and eventually the patient lost his left vision as well. Conclusion: This report is regarding a case of an invasive aspergillosis resulting in blindness in both eyes with the clinical manifestations of acute angle closure caused by invasive aspergillosis.

An atypical case of lacrimal sac fistula located on the temporal side of the lateral canthus.

We report a case of congenital lacrimal sac fistula located on the temporal side of the lateral canthus. A systemically healthy 1-year-old girl came to the outpatient clinic with a complaint of tearing on the temporal side of the right lateral canthus since birth. On examination, a small orifice was found in the skin on the temporal side of the lateral canthus. There was no evidence of inflammation or swelling within the opening. Surgeons carried out an operation under general anesthesia. They passed a probe through the lacrimal orifice and advanced it toward the lacrimal sac. Next, they introduced saline to the inferior punctum and found that it drained to the lateral fistula. The lower lid stretched as the dissected fistula was pulled. After the operation, the patient was free of the symptom. This paper is to report a case of congenital lacrimal sac fistula located on the temporal side of the lateral canthus.