1,594 research outputs found
The effect of pterygium surgery on contrast sensitivity and corneal topographic changes
No full textJoo Youn Oh, Won Ryang WeeDepartment of Ophthalmology, Seoul National University Hospital, Seoul, KoreaPurpose: To investigate the effect of pterygium surgery on corneal topography and contrast sensitivity.Patient and methods: The IRB approved this prospective, nonrandomized, self-controlled study. Computerized videokeratography (Orbscan II) was performed in 36 patients with primary pterygia, both before and 1 month after pterygium excision with limbal-conjunctival autografting. The topographic parameters were compared. Spatial contrast sensitivity testing was performed using VCTS 6500. Differences between preoperative and postoperative values were evaluated statistically.Results: The mean Sim K astigmatism and irregularity index, significantly decreased after pterygium surgery. The mean refractive power significantly increased after the operation. The “with-the-rule” astigmatism induced by pterygium became “against-the-rule” astigmatism after pterygium removal (P = 0.041). The contrast sensitivity of 6, 12, and 18 cycles per degree, significantly increased from 1.55 ± 0.28, 0.97 ± 0.47, and 0.29 ± 0.16 to 1.72 ± 0.18, 1.21 ± 0.44, and 0.65 ± 0.48, respectively (P = 0.007, <0.001, <0.001, respectively).Conclusions: Pterygium surgery significantly reduces corneal topographic astigmatism and improves contrast sensitivity.Keywords: corneal topography, visual acuit
Infliximab for progressive peripheral ulcerative keratitis in a patient with juvenile rheumatoid arthritis
No full textN
A case of corneal endothelial deterioration associated with retained Descemet`s membrane after penetrating keratoplasty
No full textIde T, 2008, OPHTHAL SURG LAS IM, V39, P422VENGAYIL S, 2008, CONT LENS ANTERIOR E, V31, P161Patel SV, 2005, AM J OPHTHALMOL, V139, P311, DOI 10.1016/j.ajo.2004.09.045Sinha R, 2003, BRIT J OPHTHALMOL, V87, P654Masket S, 1996, J CATARACT REFR SURG, V22, P139
Prospective Clinical Trial of Corneal Reconstruction With Biomaterial-Free Cultured Oral Mucosal Epithelial Cell Sheets
No full textCopyright © 2017 Wolters Kluwer Health, Inc. All rights reserved. Purpose: To investigate the efficacy and safety of transplantation with biomaterial-free cultured oral mucosal epithelial cell sheets (COMECs) for ocular reconstruction in subjects with total limbal stem cell deficiency. Methods: A prospective clinical trial (NCT02149732) was conducted in 8 subjects with total limbal stem cell deficiency after approval from the institutional review board of Seoul National University Hospital (H-0707-043-213) and the Ministry of Food and Drug Safety of Korea. COMECs were prepared in a culture system without the use of any temperature-sensitive polymers or carriers. The COMECs were transplanted without suture fixation. Four subjects underwent penetrating keratoplasty after stabilization of the COMEC transplant. Stable epithelialization, changes in visual acuity, and postoperative complications were evaluated for 6 months. Corneal cytokeratins (K) of 4 subjects who underwent penetrating keratoplasty were stained with an immunofluorescent agent. Results: The ocular surface was successfully reconstructed in 6 eyes. Complete stable epithelialization was achieved within a mean of 53.6 days. Visual improvement ($2 lines) was achieved in 62.5% of the eyes. K12 (corneal phenotype), K4, and K13 (mucosal phenotype) were well expressed in grafts after keratoplasty, whereas K1, K8, and K19 were barely expressed. No ocular infections, local tumor formation, or remarkable systemic complications were observed. Ocular reconstruction using COMECs failed in 2 eyes, which had full symblepharon in 4 quadrants. Conclusions: Transplanting biomaterial-free COMECs seems to be an efficient and safe procedure to reconstruct the ocular surface in patients who are completely limbal stem cell deficient without a full symblepharon.N
Corneal keloid: four case reports of clinicopathological features and surgical outcome
No full textThis article is distributed under the terms of the Creative Commons Attribution 4.0
International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and
reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to
the Creative Commons license, and indicate if changes were made.Abstract
Background
Surgical outcome of corneal keloid is largely variable depending on reports, although surgical management is inevitable in visually significant cases. We here report clinical features, histopathological findings, and surgical outcome of four cases of corneal keloid.
Case presentation
Four Korean male patients without a history of corneal trauma or disease were clinically and histologically evaluated for a slowly-growing, white opacity in the cornea. On slit lamp examination, corneal lesions appeared as a solitary, pearly white, well-circumscribed nodule with a smooth and glistening surface. Because the lesions involved the visual axis deteriorating the visual acuity, the nodules were surgically removed by superficial keratectomy in all patients. Amniotic membrane transplantation was combined in three patients, and an intraoperative mitomycin C application in two patients. Hematoxylin-eosin staining of the excised nodules revealed epithelial hyperplasia, Bowmans layer disruption, thick and irregularly-arranged collagen fibers in the stroma, and accumulation of prominent fibroblasts, which are consistent with the diagnosis of corneal keloid. The corneal keloids recurred in all patients within 10months of surgical excision and outgrew the boundary of the excised area.
Conclusion
A diagnosis of corneal keloid should be suspected in patients presenting with an enlarging, white, glistening corneal nodule, even in the absence of a history of corneal trauma or disease. The recurrence is common after surgical excision, and the lesion can be exacerbated by surgery
Mooren Ulcer in a Child Wearing Orthokeratology Contact Lenses
No full textPurpose: To report a case of Mooren ulcer that developed in a pediatric patient wearing orthokeratology overnight contact lenses. Methods: Case report. Results: A 10-year-old boy was referred to our clinic because of progressive peripheral corneal ulcer in the right eye, despite the intensive use of fortified antibiotic eye drops. The patient had been using overnight orthokeratology lenses for 4 months before presentation of corneal ulcer. There was no other history of ocular or systemic trauma and disorders. Microbiological tests of the lesion were negative. Systemic evaluation showed no sign of rheumatologic disease. Under a diagnosis of Mooren ulcer, the patient was treated with topical and systemic corticosteroids. After four weeks of treatment, the patient's symptoms rapidly disappeared, and corneal ulcer was healed. The vision recovered to normal with the correction of with-the-rule astigmatism. Conclusions: Mooren ulcer can develop in pediatric patients wearing orthokeratology contact lenses. Given rapid progression of Mooren ulcer in a young population, early diagnosis and proper treatment are essential to prevent a devastating outcome.N
Identification and Characterization of Phenotypic Markers of Human Mesenchymal Stem Cell-Derived Corneal Limbal Epithelial Cells
No full textPurpose: To investigate the expression of stem cell-associated and corneal differentiation markers in human bone marrow-derived MSCs (hMSCs) and to examine the influence of cell culture conditions on the potential of hMSCs to differentiate into corneal epithelial cells. Methods: We identified and characterized stern cell-associated and corneal differentiation markers in hMSCs using RT PCR and immunocytochemistry, and compared it to the marker expression seen in human corneal limbal epithelial cells (hLECs). We also examined the influence of cell Culture conditions, Such as serial passage, cell plating density, presence of feeder cells, and addition of epidermal (EGF) and fibroblast growth factors (FGF) at varying densities, oil the marker expression of hMSCs. Results: Both hMSCs and hLECs expressed Cnx43. However, hMSCs did not express p63, ABCG2, OCT4, K12, or MUC16, which were expressed in hLECs. MUC1 was highly expressed in hMSCs, while it was not expressed in hLECs. Notably, hMSCs lost the ability to express MUC1, when 20 ng/ml of EGF was added to the culture in the presence of NIH/3T3 feeder cells. However, the Culture duration, cell plating density, and use of feeder cells did not exert a significant effect oil the marker expression in hMSCs. Conclusion: P63, K12, and MUC16 can be used as putative positive markers and MUC1 as a putative negative marker for differentiation of hMSCs to hLECs. Differentiation of hMSCs into corneal epithelial-like phenotype was not induced by varying the culture duration or plating density or by using NIH/3T3 fibroblasts as a feeder.N
Effects of Mesenchymal Stem/Stromal Cells on Cultures of Corneal Epithelial Progenitor Cells With Ethanol Injury
No full textPURPOSE. Mesenchymal stem/stromal cells (MSCs) facilitate the regeneration of injured tissue. Our group has previously shown that human MSCs (hMSCs) or hMSC-derived factors suppress excessive inflammatory response in the cornea following chemical injury in vivo. We here investigated direct effects of hMSC-derived factors on cultures of chemically injured human corneal epithelial progenitor cells (hCEP), independent of systemic anti-inflammatory effects that hMSCs have been shown to have in vivo. METHODS. We injured hCEP by incubation in 20% ethanol for 30 seconds, and cultured the cells in fresh medium or in medium derived from cultures of human dermal fibroblasts (hFbs), hMSCs, or TNF-alpha-activated hMSCs. After 24 hours, we evaluated the survival, proliferation, and apoptosis of the cells. RESULTS. The hMSC-conditioned medium enhanced survival and proliferation and inhibited apoptosis of chemically injured hCEP. In addition, the conditioned medium accelerated the wound healing of corneal epithelium in tissue cultures of rabbit corneas following injury. The effects of the hMSC-conditioned medium were increased by preincubating hMSCs with TNF-alpha The increased effectiveness of the medium from the preactivated hMSCs was in part explained by increased concentration of the multifunctional protein stanniocalcin-1 that inhibits apoptosis and promotes survival of cells. CONCLUSIONS. Together, the data account for beneficial effects of hMSCs on tissue-endogenous stem cells involving hCEP, and provide a basis for using MSCs or MSC-derived factors to treat diseases of the cornea and other tissues.N
Sterically Controlled Excited-State Intramolecular Proton Transfer Dynamics in Solution
No full text© 2019 American Chemical Society.Excited-state intramolecular proton transfer (ESIPT) is a fundamental ultrafast photochemical process. Although it has been intensively studied for the development of novel photonic devices such as organic light-emitting diodes, the relation between ESIPT reaction and intramolecular charge transfer (ICT) is still a subject of debate. Furthermore, the effects of the molecular geometry and of the substituent on ESIPT and ICT processes are still unclear. To address these issues, we synthesized a set of four compounds designed to control the electron density distribution of the proton-donating (PD) group and the steric hindrance between the PD and the adjacent phenyl groups: three 2-(1-phenyl-1H-imidazo[4,5-f][1,10]phenanthrolin-2-yl)phenol derivatives, PIPP-Xs (X = H, F, and OMe), and 2-(1-phenyl-1H-imidazo[4,5-f][1,10]phenanthrolin-2-yl)naphthalen-2-ol (PIPN). We then investigated their ESIPT and ICT dynamics as well as the related structural changes using femtosecond transient absorption spectroscopy and theoretical calculations. Although the four compounds commonly exhibit a dual emission originating from the excited enol (E*) and keto (K*) tautomers, their emission properties, such as emission maxima and lifetimes, are systematically modulated by substitution at the para-position of the PD group. The experimental and time-dependent density functional theory calculation results showed that the substitution of an electron-withdrawing group at the para-position of the PD group and the planarity between the PD and proton-accepting (PA) groups play important roles in inducing an efficient ESIPT characterized by increased emission of the K∗ tautomer. On the other hand, the photoexcitation for PIPP-Xs induces the formation of cis-K*, which is the most stable structure, whereas in PIPN the E∗ tautomer generated by the photoexcitation is rapidly converted to two species, cis-K∗ and per-K∗ with time constants of <0.2 and 0.5 ps, respectively. Furthermore, the per-K∗ state of PIPN has a charge transfer characteristic, suggesting intramolecular charge migration induced by the formation of per-K∗ state. This distinctive dynamics of PIPN is due to its pretwisted structure between PD and PA groups. The results provided in this study demonstrate that the molecular geometry plays an important role in the ESIPT and ICT processes11sciescopu
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