November 2017

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Liu C-H, Wang Z, Sun Y, Chen J. Animal models of ocular angiogenesis: from development to pathologies. FASEB J 2017;31(11):4665-4681.Abstract
Pathological angiogenesis in the eye is an important feature in the pathophysiology of many vision-threatening diseases, including retinopathy of prematurity, diabetic retinopathy, and age-related macular degeneration, as well as corneal diseases with abnormal angiogenesis. Development of reproducible and reliable animal models of ocular angiogenesis has advanced our understanding of both the normal development and the pathobiology of ocular neovascularization. These models have also proven to be valuable experimental tools with which to easily evaluate potential antiangiogenic therapies beyond eye research. This review summarizes the current available animal models of ocular angiogenesis. Models of retinal and choroidal angiogenesis, including oxygen-induced retinopathy, laser-induced choroidal neovascularization, and transgenic mouse models with deficient or spontaneous retinal/choroidal neovascularization, as well as models with induced corneal angiogenesis, are widely used to investigate the molecular and cellular basis of angiogenic mechanisms. Theoretical concepts and experimental protocols of these models are outlined, as well as their advantages and potential limitations, which may help researchers choose the most suitable models for their investigative work.-Liu, C.-H., Wang, Z., Sun, Y., Chen, J. Animal models of ocular angiogenesis: from development to pathologies.
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Marmalidou A, Kheirkhah A, Dana R. Conjunctivochalasis: A Systematic Review. Surv Ophthalmol 2017;Abstract
Conjunctivochalasis (CCH) is a conjunctival condition characterized by loose, redundant conjunctival folds, most typically in the inferior bulbar conjunctiva of both eyes. Although CCH is a common cause of ocular irritation and discomfort, especially in the elderly, it is often overlooked in clinical practice. Conjunctivochalasis may be associated with various ocular and non-ocular conditions; however, the most important risk factor is aging. Although often asymptomatic, CCH may cause symptoms related to tear film instability and/or delayed tear clearance. Pathogenesis of CCH remains largely unknown, but may involve different elements such as aged conjunctiva, unstable tear film, mechanical friction, ocular surface inflammation, and delayed tear clearance. Contradictory results have been reported on histopathologic changes in CCH, with some studies showing a normal microscopic structure. For symptomatic CCH, medical treatment may include lubrication and anti-inflammatory medications. For symptomatic patients who fail to respond to medical treatment, a surgical procedure may be considered. Although various surgical procedures have been used for CCH, more often it consists of conjunctival cauterization or excision of the redundant conjunctiva, with or without amniotic membrane transplantation.
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Peterson SR, Silva PA, Murtha TJ, Sun JK. Cataract Surgery in Patients with Diabetes: Management Strategies. Semin Ophthalmol 2017;:1-8.Abstract
Diabetes is a chronic systemic disease that affects nearly one in eight adults worldwide. Ocular complications, such as cataract, can lead to significant visual impairment. Among the worldwide population, cataract is the leading cause of blindness, and patients with diabetes have an increased incidence of cataracts which mature earlier compared to the rest of the population. Cataract surgery is a common and safe procedure, but can be associated with vision-threatening complications in the diabetic population, such as diabetic macular edema, postoperative macular edema, diabetic retinopathy progression, and posterior capsular opacification. This article is a brief review of diabetic cataract and complications associated with cataract extraction in this population of patients.
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Rahman SI, Turalba A. Anticoagulation in Glaucoma Surgery. Semin Ophthalmol 2017;:1-4.Abstract
Anticoagulation medications are used commonly, particularly in an elderly population. There are many systemic diseases and scenarios that require modulation of coagulation to prevent serious adverse outcomes. While there is some consensus about their use in cataract surgery, there is less certainty about their management with glaucoma surgery. Glaucoma surgery presents a unique challenge when considering anticoagulation. Currently, there is great diversity in surgeon practices regarding anticoagulation in glaucoma surgery. Based on available evidence, it is unclear whether it is beneficial to hold anticoagulation, with or without bridging therapy, leading up to a planned surgery. Considering the potential serious adverse outcomes related to holding anticoagulation therapy, altering these medications for glaucoma surgery should be done sparingly and in consultation with the primary prescriber of such medications.
Rahmani S, Eliott D. Postoperative Endophthalmitis: A Review of Risk Factors, Prophylaxis, Incidence, Microbiology, Treatment, and Outcomes. Semin Ophthalmol 2017;:1-7.Abstract
Postoperative endophthalmitis is one of the most feared complications of intraocular surgery. The most common types of intraocular surgeries performed worldwide are cataract extraction, glaucoma drainage implants/trabeculectomy, and pars plana vitrectomy. This review will focus on the clinical features, risk factors, prophylaxis, and treatment of endophthalmitis in these three main intraocular surgeries.
Riau AK, Venkatraman SS, Dohlman CH, Mehta JS. Surface Modifications of the PMMA Optic of a Keratoprosthesis to Improve Biointegration. Cornea 2017;36 Suppl 1:S15-S25.Abstract
Biointegration of a keratoprosthesis (KPro) is critical for the mitigation of various long-term postoperative complications. Biointegration of a KPro occurs between the haptic skirt (corneal graft) and the central optic [poly(methyl methacrylate) (PMMA)]. Various studies have highlighted common problems associated with poor bonding and biointegration between these 2 incompatible biomaterials. Resolution of these issues could be achieved by surface modification of the inert material (PMMA). A calcium phosphate (CaP) coating deposited on dopamine-activated PMMA sheets by simulated body fluid incubation (d-CaP coating) was shown to improve adhesion to collagen type I (main component of corneal stroma) compared with untreated PMMA and PMMA with other surface modifications. However, the d-CaP coating could easily undergo delamination, thereby reducing its potential for modification of KPro optical cylinders. In addition, the coating did not resemble the Ca and P composition of hydroxyapatite (HAp). A novel dip-coating method that involves the creation of cavities to trap and immobilize HAp nanoparticles on the PMMA surface was introduced to address the problems associated with the d-CaP coating. The newly obtained coating offered high hydrophilicity, resistance to delamination, and preservation of the Ca and P composition of HAp. These advantages resulted in improved adhesion strength by more than 1 order of magnitude compared with untreated PMMA. With respect to biointegration, human corneal stromal fibroblasts were able to adhere strongly and proliferate on HAp-coated PMMA. Furthermore, the new coating technique could be extended to immobilization of HAp nanoparticles on 3-mm-diameter PMMA cylinders, bringing it closer to clinical application.
Roh M, Lee NG, Miller JB. Complications Assoicated with MIRAgel for Treatment of Retinal Detachment. Semin Ophthalmol 2017;:1-6.Abstract
MIRAgel (MIRA, Waltham, MA) is a hydrogel buckle that was introduced in 1979 as a new scleral implant for the treatment of retinal detachment. Long-term follow-up of more than 10 years revealed that the hydrolysis of the synthetic hydrophilic material leads to marked expansion of the substance, causing complications such as buckle extrusion and intrusion, eye motility disorder, cosmetic deformities, and periocular infections. Removal of the implant is the treatment of choice in cases with complications, but it is technically difficult due to the friability of the implant, severe scleral ectasia, and relatively high rate of redetachment after removal.
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Starks V, Freitag SK. Postoperative Complications of Dermis-Fat Autografts in the Anophthalmic Socket. Semin Ophthalmol 2017;:1-4.Abstract
Reconstruction of the anophthalmic socket allows the use of an ocular prosthesis and rehabilitation of facial appearance. Dermis-fat grafting is one option in volume augmentation of the anophthalmic socket and presents unique benefits, including increased surface area within the socket and the ability to grow with pediatric patients. Postoperative complications of this procedure are relatively common. Minor complications, such as graft hirsutism, keratinization, and conjunctival cysts or granulomas, are managed easily by observation or simple intervention. Major complications, such as graft atrophy, infection, or ulceration, may prevent good prosthesis fit and may require return to the operating room.
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Thomson BR, Souma T, Tompson SW, Onay T, Kizhatil K, Siggs OM, Feng L, Whisenhunt KN, Yanovitch TL, Kalaydjieva L, Azmanov DN, Finzi S, Tanna CE, Hewitt AW, Mackey DA, Bradfield YS, Souzeau E, Javadiyan S, Wiggs JL, Pasutto F, Liu X, John SWM, Craig JE, Jin J, Young TL, Quaggin SE. Angiopoietin-1 is required for Schlemm's canal development in mice and humans. J Clin Invest 2017;Abstract
Primary congenital glaucoma (PCG) is a leading cause of blindness in children worldwide and is caused by developmental defects in 2 aqueous humor outflow structures, Schlemm's canal (SC) and the trabecular meshwork. We previously identified loss-of-function mutations in the angiopoietin (ANGPT) receptor TEK in families with PCG and showed that ANGPT/TEK signaling is essential for SC development. Here, we describe roles for the major ANGPT ligands in the development of the aqueous outflow pathway. We determined that ANGPT1 is essential for SC development, and that Angpt1-knockout mice form a severely hypomorphic canal with elevated intraocular pressure. By contrast, ANGPT2 was dispensable, although mice deficient in both Angpt1 and Angpt2 completely lacked SC, indicating that ANGPT2 compensates for the loss of ANGPT1. In addition, we identified 3 human subjects with rare ANGPT1 variants within an international cohort of 284 PCG patients. Loss of function in 2 of the 3 patient alleles was observed by functional analysis of ANGPT1 variants in a combined in silico, in vitro, and in vivo approach, supporting a causative role for ANGPT1 in disease. By linking ANGPT1 with PCG, these results highlight the importance of ANGPT/TEK signaling in glaucoma pathogenesis and identify a candidate target for therapeutic development.
Tu Y, Jakobiec FA, Leung K, Freitag SK. Distinguishing Benign from Malignant Circumscribed Orbital Tumors in Children. Semin Ophthalmol 2017;:1-10.Abstract
An orbital neoplasm in children is an uncommon clinical finding. Clinical suspicion should be based on many factors, including its location, the nature of onset, associated systemic signs and symptoms, family and social histories, examination findings, and radiographic characteristics. We present two cases of young children of similar age with a rapid-onset orbital mass. In both cases, a circumscribed round lesion was found in the superomedial orbit. An orbital schwannoma, a benign and usually slow growing tumor, was found in the first patient. In contrast, the biopsy of the second patient, who was nearly asymptomatic, revealed a rhabdomyosarcoma. In this review, we have explored the differential diagnosis of relatively common circumscribed round orbital tumors in the pediatric population from both the radiographic (magnetic resonance imaging, MRI) and histopathologic perspectives. A review of highly unusual orbital tumors in children is also provided.
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Veronese C, Maiolo C, Mora LD, Morara M, Armstrong GW, Ciardella AP. Bilateral Large Colloid Drusen in a Young Adult. Retina 2017;37(11):e132-e134.
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Yang Y, Kazlas M, Sharma M, Friedmann A. AML presenting with a preleukemic episode and acquired heterochromia in a child with macrosomia. Pediatr Blood Cancer 2018;65(4)
Yin J, Jurkunas U. Limbal Stem Cell Transplantation and Complications. Semin Ophthalmol 2017;:1-8.Abstract
Corneal epithelial stem cells are adult somatic stem cells located at the limbus and represent the ultimate source of transparent corneal epithelium. When these limbal stem cells become dysfunctional or deficient, limbal stem cell deficiency (LSCD) develops. LSCD is a major cause of corneal scarring and is particularly prevalent in chemical and thermal burns of the ocular surface. LSCD leads to conjunctivalization of the corneal surface, neovascularization, recurrent or persistent epithelial defects, ocular surface inflammation, and scarring that, in turn, lead to decreased vision, pain, and impaired quality of life. Several techniques have been reported for limbal stem cell transplantation (LSCT). We introduce the surgical techniques, examine the success rate, and discuss the postoperative complications of conjunctival limbal autograft (CLAU), cultivated limbal stem cell transplantation (CLET), simple limbal epithelial transplantation (SLET), and limbal allograft, including keratolimbal allografts (KLAL) and living-related conjunctival allograft (LR-CLAL).
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Zhang Q, Jing S, Cheng Z, Yu Z, Dehghan S, Shamsaddini A, Yan Y, Li M, Seto D. Comparative genomic analysis of two emergent human adenovirus type 14 respiratory pathogen isolates in China reveals similar yet divergent genomes. Emerg Microbes Infect 2017;6(11):e92.Abstract
Human adenovirus type 14 (HAdV-B14p) was originally identified as an acute respiratory disease (ARD) pathogen in The Netherlands in 1955. For approximately fifty years, few sporadic infections were observed. In 2005, HAdV-B14p1, a genomic variant, re-emerged and was associated with several large ARD outbreaks across the U.S. and, subsequently, in Canada, the U.K., Ireland, and China. This strain was associated with an unusually higher fatality rate than previously reported for both this prototype and other HAdV types in general. In China, HAdV-B14 was first observed in 2010, when two unrelated HAdV-B14-associated ARD cases were reported in Southern China (GZ01) and Northern China (BJ430), followed by three subsequent outbreaks. While comparative genomic analysis, including indel analysis, shows that the three China isolates, with whole genome data available, are similar to the de Wit prototype, all are divergent from the U.S. strain (303600; 2007). Although the genomes of strains GZ01 and BJ430 are nearly identical, as per their genome type characterization and percent identities, they are subtly divergent in their genome mutation patterns. These genomes indicate possibly two lineages of HAdV-B14 and independent introductions into China from abroad, or subsequent divergence from one; CHN2012 likely represents a separate sub-lineage. Observations of these simultaneously reported emergent strains in China add to the understanding of the circulation, epidemiology, and evolution of these HAdV pathogens, as well as provide a foundation for developing effective vaccines and public health strategies, including nationwide surveillance in anticipation of larger outbreaks with potentially higher fatality rates associated with HAdV-B14p1.

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