EVALUATING ULTRA-WIDEFIELD IMAGING UTILITY IN THE DETECTION OF TREATMENT-REQUIRING PERIPHERAL RETINAL TEARS AND HOLES.

PURPOSE: To determine the utility of ultra-widefield (UWF) imaging in detecting pathologic peripheral retinal tears and holes. METHODS: This was a retrospective, observational study. One-hundred ninety-eight eyes of 198 patients diagnosed with acute posterior vitreous detachment were included. Eyes were divided into two groups: 89 eyes with peripheral retinal holes and tears treated with laser retinopexy (treatment group) and 109 control eyes. Patients underwent UWF imaging and indirect ophthalmoscopy with scleral depression. UWF images from both groups were reviewed by two blinded graders and then compared with funduscopic examination and medical records. RESULTS: UWF imaging identified 60 of the 89 eyes (sensitivity of 67.4%) found to have treatment-requiring peripheral retinal lesions and 107 of the 109 control eyes (specificity of 98.2%).The distribution of misses based on octant location did reach statistical significance ( P = 0.004). Lesions anterior to the equator were more likely to be missed (21/41 eyes, 51.2%) compared with those located posterior to the equator (4/20 eyes, 25.0%) and at the equator (4/28, 14.3%), P = 0.002. The combined discordance rate between graders in the entire cohort was 12.1% (24/198 eyes) yielding an interrater agreement of 87.9%. CONCLUSION: UWF imaging showed a moderate sensitivity and high specificity in detecting treatment-requiring retinal tears and holes, with high interrater agreement. Given there is only a moderate sensitivity in identifying treatment-requiring retinal tears and holes, UWF imaging can assist with clinical examination, but a 360-degree scleral depressed examination should remain the gold standard.

Mitogen-Activated Pathway Kinase Inhibitor-Associated Retinopathy: Do Features Differ with Upstream versus Downstream Inhibition?

Introduction: Many cancers have derangement of the mitogen-activated pathway kinase (MAPK), making this pathway blockade a therapeutic target. However, inhibitors of MAPK can result in adverse effects including retinopathy. This study compares clinical and morphological characteristics of serous retinal disturbances in patients taking agents with variable inhibition of MAPK: either direct interference of mitogen-activated protein kinase kinase (MEK) or extracellular signal-regulated kinase (ERK) inhibitors or with indirect inhibition via interference with FGFR signaling. Methods: This retrospective observational study of prospectively collected pooled data is from a single tertiary oncology referral center. Of 339 patients receiving MAPK inhibitors (171, 107, and 61 on FGFR, MEK, and ERK inhibitors, respectively) for treatment of metastatic cancer, this study included 128 eyes of 65 patients with evidence of retinopathy confirmed by optical coherence tomography (OCT). The main outcome was characteristics of treatment-emergent choroid/retinal OCT abnormalities as compared to baseline OCT. Results: In all patients on one of three drug classes (FGFRi, MEKi, ERKi), the retinopathy manifested as subretinal fluid foci that were bilateral, fovea involving, and reversible without intervention. There were notable differences between the three classes of drugs: the proportion of patients with retinopathy, number of fluid foci per eye, proportion of eyes with intraretinal edema, and the proportion of symptomatic patients was least for the upstream target (FGFR inhibitors) and greatest for the downstream targets (MEK or ERK inhibitors). Conclusion: This study shows MAPK pathway inhibitors may cause subretinal fluid foci with unique clinical and morphological characteristics depending on the target (FGFR, MEK, or ERK) implicated. Retinopathy is more common, more symptomatic, and more severe (more fluid foci, more expansive fluid configurations) the further downstream the MAPK pathway is inhibited.

Central retinal vein occlusion in the setting of fibroblast growth factor receptor inhibition.

Purpose: To report a case of central retinal vein occlusion (CRVO) in a patient being treated with a fibroblast growth factor receptor (FGFR) inhibitor. Observations: A 54-year-old female patient with endometrial cancer presented with CRVO and cystoid macular edema while receiving lenvatinib/pembrolizumab combination therapy. The patient received treatment with intravitreal bevacizumab, after which her visual acuity improved markedly, permitting the continuation of her chemotherapy regimen without recurrence of ocular adverse events. Conclusions and Importance: Like mitogen-activated protein kinase inhibitors, FGFR inhibitors have the potential to be associated with retinal vein occlusion. In this case, visual recovery was possible with intravitreal anti-vascular endothelial growth factor therapy, and toxicity did not recur with drug reinitiation and continuation over five years of follow-up.

Multilayered macular hemorrhages as an unusual complication of transorbital neuroendoscopic surgery.

Purpose: To report a case of multilayered intraocular hemorrhage at the posterior pole as a complication of transorbital neuroendoscopic surgery. Observations: Our patient underwent an uncomplicated endoscopic transorbital resection of a left sphenoid wing meningioma. In the immediate post-operative period, the patient reported blurred vision of her left eye, and dilated fundus examination demonstrated multilayered hemorrhages at the posterior pole. No intracranial hemorrhage was identified on post-operative imaging. Due to persistent subnormal visual acuity and non-clearing hemorrhage over several weeks of follow-up, a pars plana vitrectomy with peeling of the internal limiting membrane was performed to clear the hemorrhagic component obscuring the macula. Conclusions and Importance: We report the first case of multilayered intraocular hemorrhages at the posterior pole, mimicking Terson syndrome, in the absence of intracranial hemorrhage or elevated intracranial pressure as a complication of transorbital surgery.

Mesenchymal stem cells augment regulatory T cell function via CD80-mediated interactions and promote allograft survival.

Mesenchymal stem cells (MSCs) and regulatory T cells (Tregs) both have been shown to modulate the alloimmune response and promote transplant survival. Mounting evidence suggests that MSCs augment Treg function, but the mechanisms underlying this phenomenon have not been fully deciphered. Here, we identified that MSCs express substantial levels of CD80 and evaluated its immunoregulatory function using in vivo and in vitro experiments. Our in vitro culture assays demonstrated that MSCs induce expression of FoxP3 in Tregs in a contact-dependent manner, and the blockade of CD80 abrogates this FoxP3 induction and Treg-mediated suppression of T cell proliferation. Moreover, supplementation of soluble CD80 significantly upregulated FoxP3 expression. Using a well-characterized murine model of corneal transplantation, we show that silencing CD80 in MSCs diminishes the capacity of MSCs to promote selective graft infiltration of Tregs, promote FoxP3 expression and upregulate suppressive function of Tregs. Consequently, MSCs, following CD80 knockdown, failed to promote corneal allograft survival.

Optical Coherence Tomography Angiography: Clinical Utility and Future Directions.

Purpose: This work aims to review the principles of optical coherence tomography angiography (OCTA), to survey its clinical utility, and to highlight the strengths of this technology as well as barriers to adoption. Methods: A literature review with editorial discussion of the current applications for OCTA is presented. Results: There have been recent advances in multiple domains in OCTA imaging, including devices, algorithms, and new observations pertaining to a range of pathologies. New devices have improved the scanning speed, signal-to-noise ratio, and spatial resolution and offer an increased field of view. New algorithms have been proposed to optimize image processing and reduce artifacts. Numerous studies employing OCTA have been published describing changes to the microvasculature in diabetic retinopathy, age-related macular degeneration, central serous chorioretinopathy, retinal vein occlusion, and uveitis. Conclusions: OCTA provides noninvasive, high-resolution volumetric scans of the retinal and choroidal vasculature. OCTA can provide valuable data to augment traditional dye-based angiography in a range of chorioretinal diseases.

The role of Th17 immunity in chronic ocular surface disorders.

Th17 cells have been implicated in the pathogenesis of numerous inflammatory and autoimmune conditions. At the ocular surface, Th17 cells have been identified as key effector cells in chronic ocular surface disease. Evidence from murine studies indicates that following differentiation and expansion, Th17 cells migrate from the lymphoid tissues to the eye, where they release inflammatory cytokines including, but not limited to, their hallmark cytokine IL-17A. As the acute phase subsides, a population of long-lived memory Th17 cells persist, which predispose hosts both to chronic inflammation and severe exacerbations of disease; of great interest is the small subset of Th17/1 cells that secrete both IL-17A and IFN-γ in acute-on-chronic disease exacerbation. Over the past decade, substantial progress has been made in deciphering how Th17 cells interact with the immune and neuroimmune pathways that mediate chronic ocular surface disease. Here, we review (i) the evidence for Th17 immunity in chronic ocular surface disease, (ii) regulatory mechanisms that constrain the Th17 immune response, and (iii) novel therapeutic strategies targeting Th17 cells.

ALTITUDE-ASSOCIATED INTRAOCULAR PRESSURE CHANGES IN A GAS-FILLED EYE.

PURPOSE: Intraocular gases are commonly used in vitreoretinal surgery. Patients are routinely advised against air travel before the complete absorption of intraocular gas. Consequently, reports on air travel in patients with large intraocular gas bubbles are highly unusual. Here, we report the intraocular pressure changes of a patient ascending to an altitude of 2,600 feet in a helicopter with a 50% fill perfluoropropane (C3F8) gas bubble in his left eye. METHODS: Case report and literature review. RESULTS: A 61-year-old male patient underwent pars plana vitrectomy for a rhegmatogenous retinal detachment, with fluid-gas exchange using 16% C3F8. With a 50% fill bubble in the left eye, the patient took a short helicopter trip ascending to a maximum altitude of 2,600 feet. Before take-off, intraocular pressure in the operated eye was 14 mmHg. The average increase in intraocular pressure was 10.8 mmHg per 1,000 feet of ascent, with a maximum recorded intraocular pressure of 42 mmHg. The patient denied both ocular pain and loss of vision but did report changes in the appearance of the gas bubble meniscus at 2,100 feet. CONCLUSION: Short-term low-altitude air travel may be tolerated by some patients with intraocular gas in situ. Further studies are required to define the conditions by which patients with gas bubbles may fly safely.

Characterization of Clinical and Immune Responses in an Experimental Chronic Autoimmune Uveitis Model.

Autoimmune uveitis is a sight-threatening intraocular inflammatory disease. For >30 years, the mouse model of experimental autoimmune uveitis has been employed to investigate disease mechanisms and test immunotherapeutic approaches. However, inflammation in this model is self-limited, and does not replicate the chronic, insidious nature prevalent in the human disease. Herein, a robust and reliable model of chronic autoimmune uveitis was developed and characterized in two strains of wild-type mice by modifying interphotoreceptor retinoid-binding protein dose and peptide fragments from conventional experimental autoimmune uveitis models. In both of these murine strains, immunization with our modified protocols resulted in a slowly progressive uveitis, with retinal scars and atrophy observed in the chronic stage by fundoscopy. Optical coherence tomography demonstrated decreased retinal thickness in chronic autoimmune uveitis mice, and electroretinography showed significantly reduced amplitudes of dark-adapted a- and b-waves and light-adapted b-waves. Histologic examination revealed prominent choroiditis with extensive retinal damage. Flow cytometry analysis showed substantially increased numbers of CD44hiIL-17+IFN-γ- memory T-helper 17 (Th17) cells in the retina, cervical lymph nodes, inguinal lymph nodes, and spleen. These data establish new modified protocols for inducing chronic uveitis in wild-type mice, and demonstrate a predominant memory Th17 cell response, suggesting an important role for memory Th17 cells in driving chronic inflammation in autoimmune uveitis.

Epithelium-derived IL-33 activates mast cells to initiate neutrophil recruitment following corneal injury.

PURPOSE: Neutrophils play a critical role in defending against threats such as microbial infection, yet their activation during innate immune response incites collateral damage to healthy tissues. We have previously shown that corneal injury induces mast cells to express the neutrophil chemoattractant CXCL2. Here we delineate the mechanism of injury-induced, non-IgE-mediated mast cell activation at the ocular surface. METHODS: Corneal injury was induced by mechanical removal of the epithelium and anterior stroma in mast cell deficient (cKitW-sh) and C57BL/6 mice using Algerbrush II. Corneas were analyzed for frequencies of total CD45+ inflammatory cells, CD11b+Ly6G+ neutrophils, and cKit+FcεR1+ mast cells using flow cytometry. Mast cells were stimulated with different inflammatory factors known to increase during corneal injury (IL-33, IL-1ß, IL-36γ, IL-6, SDF1α and Substance P) and assessed for the secretion of ß-hexosaminidase, tryptase and CXCL2 using ELISA. IL-33 neutralizing antibody (1 mg/ml) was administered locally for mast cell inhibition in vivo. RESULTS: Mast cell deficient mice failed to recruit early neutrophils to the injured corneas. IL-33 stimulation upregulated CXCL2 secretion by mast cells. Corneal injury resulted in amplified expression of IL-33 at the cornea and epithelium was identified as its primary source. Topical neutralization of IL-33 at the ocular surface inhibited mast cell activation, limited neutrophil infiltration, and reduced corneal inflammatory haze, normalizing tissue architecture following ocular injury. CONCLUSIONS: These data implicate IL-33 in mast cell activation and early neutrophil recruitment in non-allergic inflammation, suggesting IL-33 as a potential therapeutic target in inflammatory disorders of the ocular surface.

Aged Mice Exhibit Severe Exacerbations of Dry Eye Disease with an Amplified Memory Th17 Cell Response.

The prevalence as well as the severity of dry eye disease increase with age. Memory T helper 17 (Th17) cells (CD4+IL-17A+CD44+) drive the chronic and relapsing course of dry eye disease. Here, we investigated the contribution of memory Th17 cells to age-related dry eye disease, and evaluated memory Th17 cell depletion with anti-IL-15 antibody as a strategy to abrogate the severe exacerbations of dry eye disease observed in aged mice. After initial exposure to desiccating stress, aged mice maintained higher frequencies of memory Th17 cells in the draining lymph nodes relative to young mice. Upon secondary exposure to desiccating stress, aged mice developed more severe corneal epitheliopathy than young mice, which is associated with increased local frequencies of Th17 cells (CD4+IL-17A+). Treatment with anti-IL-15 antibody decreased the enlarged memory Th17 pool in aged mice to frequencies comparable with young mice. Furthermore, anti-IL-15-treated mice showed significantly reduced conjunctival infiltration of Th17 cells and lower corneal fluorescein staining scores compared with saline-treated control mice. Our data suggest that age-related increases in the memory Th17 compartment predispose aged mice toward the development of severe corneal epithelial disease after exposure to a dry environment. Selectively targeting memory Th17 cells may be a viable therapeutic approach in the treatment of age-related dry eye disease.

Regulatory T cells promote corneal endothelial cell survival following transplantation via interleukin-10.

The functional competence of corneal endothelial cells (CEnCs) is critical for survival of corneal allografts, but these cells are often targets of the immune response mediated by graft-attacking effector T cells. Although regulatory T cells (Tregs) have been studied for their role in regulating the host's alloimmune response towards the graft, the cytoprotective function of these cells on CEnCs has not been investigated. The aim of this study was to determine whether Tregs suppress effector T cell-mediated and inflammatory cytokine-induced CEnC death, and to elucidate the mechanism by which this cytoprotection occurs. Using 2 well-established models of corneal transplantation (low-risk and high-risk models), we show that Tregs derived from low-risk graft recipients have a superior capacity in protecting CEnCs against effector T cell-mediated and interferon-γ and tumor necrosis factor-α-induced cell death compared to Tregs derived from high-risk hosts. We further demonstrate that the cytoprotective function of Tregs derived from low-risk hosts occurs independently of direct cell-cell contact and is mediated by the immunoregulatory cytokine IL-10. Our study is the first to report that Tregs provide cytoprotection for CEnCs through secretion of IL-10, indicating potentially novel therapeutic targets for enhancing CEnC survival following corneal transplantation.

Keratoconus progression associated with hormone replacement therapy.

PURPOSE: To report a postmenopausal patient with keratoconus who experienced significant progression after using hormone replacement therapy. OBSERVATIONS: A 51-year-old woman with previously stable keratoconus presented with acute disease progression following hormone replacement therapy in the context of prophylactic hysterectomy and bilateral ovariosalpingectomy. Over a 14-month period after starting hormone therapy, the steepest K increased from 63.7D to 71.5D in the right eye and from 65.8D to 78.1D in the left eye. CONCLUSIONS: Hormone replacement therapy may amplify progression of keratoconus.

Therapeutic efficacy of different routes of mesenchymal stem cell administration in corneal injury.

PURPOSE: Corneal injuries are associated with significant impairment in vision. Mesenchymal stem cells (MSCs) have been shown to limit inflammation and promote tissue repair at the ocular surface. Here, we evaluate the efficacies of different modes of MSC delivery (topical, subconjunctival, intraperitoneal [IP] and intravenous [IV]) to promote tissue repair and restore corneal transparency in a murine model of corneal injury. METHODS: MSCs were purified from the bone marrow of C57BL/6  mice and expanded using plastic adherence in vitro. Corneal injury was created using an Algerbrush, and 0.5 × 106 MSCs/mouse were administered via topical, subconjunctival, IP or IV routes. Qdot-labeled MSCs were employed to determine the effect of route of administration on corneal and conjunctival MSC frequencies. Corneal opacity scores were calculated using ImageJ. Expression of inflammatory cytokines was quantified by qPCR, and infiltration of CD45+ cells was evaluated by flow cytometry. RESULTS: Subconjunctival or IV administration results in increased frequencies of MSCs in ocular surface tissues following corneal injury, relative to topical or intraperitoneal delivery. Subconjunctival or IV administration reduces: (i) corneal opacity, (ii) tissue fibrosis as quantified by α-Sma expression, (iii) the expression of inflammatory cytokines (Il-1ß and Tnf-α) and (iv) CD45+ inflammatory cell infiltration relative to untreated injured control animals. Administration via subconjunctival or IV routes was observed to accelerate corneal repair by restoring tissue architecture and epithelial integrity. CONCLUSIONS: Our data suggest that subconjunctival or IV delivery of MSCs has superior therapeutic efficacy compared to topical or IP delivery following corneal injury.

Mesenchymal Stromal Cells Modulate Corneal Alloimmunity via Secretion of Hepatocyte Growth Factor.

Mesenchymal stromal cells (MSCs) are multipotent stem cells that participate in tissue repair and possess considerable immunomodulatory potential. MSCs have been shown to promote allograft survival, yet the mechanisms behind this phenomenon have not been fully defined. Here, we investigate the capacity of MSCs to suppress the allogeneic immune response by secreting the pleiotropic molecule hepatocyte growth factor (HGF). Using an in vivo mouse model of corneal transplantation, we report that MSCs promote graft survival in an HGF-dependent manner. Moreover, our data indicate that topically administered recombinant HGF (a) suppresses antigen-presenting cell maturation in draining lymphoid tissue, (b) limits T-helper type-1 cell generation, (c) decreases inflammatory cell infiltration into grafted tissue, and (d) is itself sufficient to promote transplant survival. These findings have potential translational implications for the development of HGF-based therapeutics. Stem Cells Translational Medicine 2019;8:1030-1040.

Thrombospondin-1 in ocular surface health and disease.

Thrombospondin 1 (TSP-1) is an extracellular matrix protein that interacts with a wide array of ligands including cell receptors, growth factors, cytokines and proteases to regulate various physiological and pathological processes. Constitutively expressed by certain ocular surface tissues (e.g. corneal and conjunctival epithelium), TSP-1 expression is modulated during ocular surface inflammation. TSP-1 is an important activator of latent TGF-ß, serving to promote the immunomodulatory and wound healing functions of TGF-ß. Mounting research has deepened our understanding of how TSP-1 expression (and lack thereof) contributes to ocular surface homeostasis and disease. Here, we review current knowledge of the function of TSP-1 in dry eye disease, ocular allergy, angiogenesis/lymphangiogenesis, corneal transplantation, corneal wound healing and infectious keratitis.

The purinergic receptor antagonist oxidized adenosine triphosphate suppresses immune-mediated corneal allograft rejection.

Adenosine triphosphate (ATP) is released into the extracellular environment during transplantation, and acts via purinergic receptors to amplify the alloimmune response. Here, using a well-established murine model of allogeneic corneal transplantation, we investigated the immunomodulatory mechanisms of the purinergic receptor antagonist oxidized ATP (oATP). Corneal transplantation was performed using C57BL/6 donors and BALB/c hosts. oATP or sterile saline was administered via intraperitoneal injection for 2 weeks postoperatively. Frequencies of CD45+ leukocytes, CD11b+MHCII+ antigen presenting cells (APCs), CD4+IFN-γ+ effector Th1 cells and CD4+Foxp3+ regulatory T cells (Tregs) were evaluated by flow cytometry. Slit-lamp microscopy was performed weekly for 8 weeks to evaluate graft opacity and determine transplant rejection. Treatment with oATP was shown to significantly reduce graft infiltration of CD45+ leukocytes, decrease APC maturation and suppress effector Th1 cell generation relative to saline-treated control. No difference in Treg frequencies or Foxp3 expression was observed between the oATP-treated and control groups. Finally, oATP treatment was shown to reduce graft opacity and increase graft survival. This report demonstrates that oATP limits the alloimmune response by regulating APC maturation and suppressing the generation of alloreactive Th1 immunity.

Oral guaifenesin for treatment of filamentary keratitis: A pilot study.

PURPOSE: Pilot study to evaluate the safety and efficacy of oral guaifenesin in reducing the signs and symptoms of filamentary keratitis. METHODS: Prospective, uncontrolled open-label pilot study. Twelve patients with non-Sjögren dry eye disease (DED) and secondary filamentary keratitis received treatment with oral guaifenesin 600 mg twice a day (total dose of 1.2 g/day) for 4 weeks. Adverse events, change in the number of corneal filaments, corneal fluorescein staining (CFS; NEI grading system), and symptoms (Ocular Surface Disease Index) were assessed. RESULTS: Before starting oral guaifenesin, all patients were on topical medical therapy for their condition. At baseline, the mean number of filaments was 5.8 ±â€¯2.9, CFS score 7.3 ±â€¯3.2, and OSDI score 55.6 ±â€¯25. After 4 weeks of treatment, the number of filaments was 2.1 ±â€¯2.2 (p = 0.04 vs. baseline), CFS score 6.5 ±â€¯3.1 (p = 0.5), and OSDI score 46.1 ±â€¯30.9 (p = 0.2). One patient discontinued the medication due to gastrointestinal side effects. CONCLUSIONS: Oral guaifenesin was safe and generally well tolerated, and demonstrated modest efficacy in reducing the severity of filamentary keratitis. These results should be considered preliminary; however, placebo-controlled investigations would be justified to evaluate the therapeutic efficacy of oral guaifenesin as a mucolytic in treatment of filamentary keratitis.