Cornea

Cornea Publications

Gonzalez-Andrades M, Sharifi R, Islam M-M, Divoux T, Haist M, Paschalis E, Gelfand L, Mamodaly S, Di Cecilia L, Cruzat A, Ulm F-J, Chodosh J, Delori F, Dohlman CH. Improving the practicality and safety of artificial corneas: Pre-assembly and gamma-rays sterilization of the boston keratoprosthesis. Ocul Surf 2018;Abstract
PURPOSE: To make the Boston keratoprosthesis (B-KPro), together with its carrier corneal graft, more easily procured, transported and stored, as well as less expensive, easier for the surgeon to implant and safer for the patient, it is proposed that the B-KPro-graft combination be pre-assembled by an expert technician, followed by sterilization with gamma ray irradiation (GI) allowing long-term storage at room temperature. For this to be possible, it must be shown that the B-KPro itself (not only the graft) remains unharmed by the irradiation. METHODS: Polymethyl methacrylate (PMMA) discs and B-KPros were submitted to either ethylene oxide sterilization or different doses of GI. Cell biocompatibility, mechanical strength and optical quality were evaluated. The feasibility of assembling the B-KPro to a corneal graft, and gamma-radiate afterwards, was also assessed. RESULTS: There were no differences in cell biocompatibility between the samples. The optical evaluation showed high levels of transparency for all the groups. The absorbance of ultraviolet was higher for the groups treated with GI. The mechanical evaluation by nanoindentation showed no alterations of the PMMA discs after GI. The flexure test revealed a similar mechanical behavior. Technically, pre-assembly and GI of the B-KPro revealed no problems. CONCLUSIONS: Sterilization of B-KPro using GI has no detrimental influence on the device. The pre-assembly of B-KPro to a donor cornea, followed by gamma sterilization, emerges as an efficient and safe procedure.
Lippestad M, Hodges RR, Utheim TP, Serhan CN, Dartt DA. Signaling pathways activated by resolvin E1 to stimulate mucin secretion and increase intracellular Ca in cultured rat conjunctival goblet cells. Exp Eye Res 2018;Abstract
Glycoconjugate mucin secretion from conjunctival goblet cells is tightly regulated by nerves and specialized pro-resolving mediators (SPMs) to maintain ocular surface health. Here we investigated the actions of the SPM resolvin E1 (RvE1) on cultured rat conjunctival goblet cell glycoconjugate secretion and intracellular [Ca] ([Ca]) and the signaling pathways used by RvE1. Goblet cells were cultured from rat conjunctiva in RPMI medium. The amount of RvE1-stimulated glycoconjugate mucin secretion was determined using an enzyme-linked lectin assay with Ulex Europaeus Agglutinin 1 lectin. Cultured goblet cells were also incubated with the Ca indicator dye fura 2/AM and [Ca] was measured. Cultured goblet cells were incubated with inhibitors to phospholipase (PL-) C, D, and A2 signaling pathways. RvE1 stimulated glycoconjugate secretion in a concentration dependent manner and was inhibited with the Ca chelator BAPTA. The Ca response was also increased in a concentration manner when stimulated by RvE1. Inhibition of PLC, PLD, and PLA2, but not Ca/calmodulin-dependent kinase blocked RvE1-stimulated increase in [Ca] and glycoconjugate secretion. We conclude that under normal, physiological conditions RvE1 stimulates multiple pathways to increase glycoconjugate secretion and [Ca]. RvE1 could be an important regulator of goblet cell glycoconjugate mucin secretion to maintain ocular surface health.
Amparo F, Dana R. Web-based longitudinal remote assessment of dry eye symptoms. Ocul Surf 2018;16(2):249-253.Abstract
PURPOSE: To investigate the feasibility of remote assessment and follow-up of dry eye symptoms using electronic versions of two validated questionnaires. METHODS: We conducted a prospective study of consecutive patients with dry eye disease (DED). Patients were enrolled during a clinical visit and were explained how to respond electronic versions of the Ocular surface Disease Index (OSDI) and the Symptom Assessment in Dry Eye (SANDE) questionnaires using a computer in the presence of investigators. A secure link to both questionnaires was sent to each patient every 2 weeks in order to respond and submit their symptoms over a 3-month period. We analyzed the number of patients who responded to both questionnaires, the recurrence, and the symptoms scores reported. RESULTS: A total of 1121 questionnaires were collected; 103 patients (85%) reported their symptoms at least once during the 3-month study duration. The majority of participants who completed the study (71.6%) responded remotely at least once per month during the 3-month duration of the study. The mean OSDI and SANDE scores from the total of remote evaluations were 34.9 ± 21.9 (range 0-97.5) and 50.3 ± 24.9 (range 0-100), respectively. There was a statistically significant correlation between the total scores collected with the two questionnaires (R = 0.67, P < 0.001). CONCLUSIONS: Patients are motivated to report DED symptoms while away from the clinic. Distance-based evaluation of DED symptoms is both feasible and convenient, and can be implemented to follow symptoms in large populations with chronic dry eye.
Eghrari AO, Vasanth S, Gapsis BC, Bison H, Jurkunas U, Riazuddin AS, Gottsch JD. Identification of a Novel TCF4 Isoform in the Human Corneal Endothelium. Cornea 2018;Abstract
PURPOSE: Alternative splice isoforms of TCF4, a gene implicated in Fuchs corneal dystrophy, have been identified in multiple human tissues outside of the eye. The aim of this study was to identify the transcriptional profile of TCF4 in the corneal endothelium. METHODS: We extracted RNA from the donor corneal endothelium and performed rapid amplification of cDNA ends. We tested the expression pattern of 1 newly identified isoform (7b) in a panel of cDNA derived from multiple human tissues and included cDNA from corneal endothelial (CE) and retinal pigment epithelial cell lines. To further delineate differential expression of TCF4 splice variants that span CTG18.1, we analyzed expression of 6 alternative splice isoforms that are transcribed from either exon 2 or 3 in RNA extracted from the corneal endothelium of 3 normal donors and a CE cell line. RESULTS: We identified 11 different isoforms in control CE tissue, including 1 isoform (7b) not reported previously. This isoform is enriched specifically in the corneal endothelium and placenta compared with other tissues in a panel of human cDNA. CONCLUSIONS: We demonstrate the complex expression profile of TCF4 in the human corneal endothelium and reveal expression of alternative splice variants of TCF4.
O'Neil EC, Huang J, Suhler EB, Dunn JP, Perez VL, Gritz DC, McWilliams K, Peskin E, Ying G-S, Bunya VY, Maguire MG, Kempen JH. Iontophoretic delivery of dexamethasone phosphate for non-infectious, non-necrotising anterior scleritis, dose-finding clinical trial. Br J Ophthalmol 2018;Abstract
Currently available treatment options for non-infectious scleritis, including non-steroidal anti-inflammatory drugs, systemic corticosteroids and immunosuppressive therapies, have both efficacy and side effect limitations. Iontophoretic delivery of corticosteroids has been demonstrated to be effective for anterior uveitis and represents a potential new approach to scleritis therapy. We hypothesised that iontophoretic delivery would provide effective and precise medication delivery to the sclera, while limiting systemic exposure and side effects. This first-in-human randomised, double-masked, dose-escalating study of iontophoretic administration of dexamethasone phosphate for scleritis suggests the treatment to be well tolerated and safe (within the limitations of the 18 patients sample size). There was a suggestion of efficacy in the lowest (1.2 mA/min at 0.4 mA) dose group (corresponding to the superficial location of scleritis compared with anterior uveitis), with 5/7 eyes meeting the primary efficacy outcome within 28 days. Our results suggest iontophoretic delivery of corticosteroids is a promising potential treatment for scleritis, with favourable safety and preliminary efficacy results in this phase 1 trial. TRIAL REGISTRATION NUMBER: NCT01059955.
Sahu SK, Mittal SK, Foulsham W, Li M, Sangwan VS, Chauhan SK. Mast Cells Initiate the Recruitment of Neutrophils Following Ocular Surface Injury. Invest Ophthalmol Vis Sci 2018;59(5):1732-1740.Abstract
Purpose: The purpose of this study was to investigate the contribution of mast cells to early neutrophil recruitment during ocular inflammation. Methods: In a murine model of corneal injury, the epithelium and anterior stroma were removed using a handheld motor brush. Cromolyn sodium (2% in PBS) eye drops were administered topically for mast cell inhibition. In vitro, bone marrow-derived mast cells were cultured alone or with corneal tissue. The frequencies of CD45+ inflammatory cells, CD11b+Ly6G+ neutrophils, and ckit+FcεR1+ mast cells in the cornea were assessed by flow cytometry. mRNA expression of CXCL2 was evaluated by real-time PCR and protein expression by ELISA. β-Hexosaminidase assays were performed to gauge mast cell activation. Results: Neutrophil infiltration of the cornea was observed within 1 hour of injury, with neutrophil frequencies increasing over subsequent hours. Concurrent expansion of mast cell frequencies at the cornea were observed, with mast cell activation (assessed by β-hexosaminidase levels) peaking at 6 hours after injury. Evaluation of CXCL2 mRNA and protein expression levels demonstrated augmented expression by injured corneal tissue relative to naïve corneal tissue. Mast cells were observed to constitutively express CXCL2, with significantly higher expression of CXCL2 protein compared with naïve corneal tissue. Culture with harvested injured corneas further amplified CXCL2 expression by mast cells. In vivo, mast cell inhibition was observed to decrease CXCL2 expression, limit early neutrophil infiltration, and reduce inflammatory cytokine expression by the cornea. Conclusions: Our data suggest that mast cell activation after corneal injury amplifies their secretion of CXCL2 and promotes the initiation of early neutrophil recruitment.
Micera A, Di Zazzo A, Esposito G, Longo R, Foulsham W, Sacco R, Sgrulletta R, Bonini S. Age-Related Changes to Human Tear Composition. Invest Ophthalmol Vis Sci 2018;59(5):2024-2031.Abstract
Purpose: We characterize age-associated alterations in the expression of inflammatory mediators and tissue remodeling factors in human tears. Methods: A total of 75 consecutive volunteers (32 male/44 female; 19-93 years) underwent clinical assessment of ocular surface status, ocular surface disease index (OSDI) grading and tear sampling. The volunteers were categorized into three groups: young (18-40 years), middle-aged (41-60 years), and old (>60 years). Total protein profiles and chip-based protein array evaluations were conducted to investigate the expression of 60 potential candidates, including pro-/anti-inflammatory mediators and tissue remodeling factors. Appropriate validations were performed using conventional assays. Multiple comparisons for regression between potential candidates and age were performed, as well as statistical analyses among the three age groups. Nonpooled samples were used for quantifications. Results: Pearson analysis of chip-arrays identified 9 of 60 potential candidates. Specifically, IL-8, IL-6, and regulated on activation, normal T cell expressed and secreted (RANTES; P < 0.0083) protein as well as matrix metalloproteinase (MMP)-1, IL-3, and TNF-α (P < 0.05) correlated positively with aging. MIP-3β showed an opposite tendency. Western blot and ELISA analysis corroborated the array data. OSDI grading did not correlate with aging. Conclusions: Dynamic changes to tear protein profiles occur with aging. Our study identifies the expression of IL-8, IL-6, RANTES, MMP-1, and MIP-3β as increasing with age. These select inflammatory and matrix remodeling factors may be relevant to the development of novel diagnostic tools and therapeutics in the context of age-related ocular surface disease.
Foulsham W, Coco G, Amouzegar A, Chauhan SK, Dana R. When Clarity Is Crucial: Regulating Ocular Surface Immunity. Trends Immunol 2018;39(4):288-301.Abstract
The ocular surface is a unique mucosal immune compartment in which anatomical, physiological, and immunological features act in concert to foster a particularly tolerant microenvironment. These mechanisms are vital to the functional competence of the eye, a fact underscored by the devastating toll of excessive inflammation at the cornea - blindness. Recent data have elucidated the contributions of specific anatomical components, immune cells, and soluble immunoregulatory factors in promoting homeostasis at the ocular surface. We highlight research trends at this distinctive mucosal barrier and identify crucial gaps in our current knowledge.
Xie H-T, Li J, Liu Y, Jiang D-L, Shen R-F, Zhang M-C. Cryopreserved limbal lamellar keratoplasty for peripheral corneal and limbal reconstruction. Int J Ophthalmol 2018;11(4):699-702.Abstract
This study aimed to evaluate the outcomes and described the recovery process of cryopreserved limbal lamellar keratoplasty (CLLK) for peripheral corneal and limbal diseases. Thirteen eyes of 12 patients with a mean age of 41±23.9y were included. The average follow-up was 12.1±5.6mo. Stable ocular surface was achieved in all eyes at last follow-up. Epithelialization originated from both recipient and graft in 9 eyes. We conclude that CLLK compensates for the shortage of donor corneas and cryopreserved limbal grafts provide epithelialization sources in ocular surface reconstruction.
Siatiri H, Mirzaee-Rad N, Aggarwal S, Kheirkhah A. Combined Tenonplasty and Scleral Graft for Refractory Scleritis Following Pterygium Removal with Mitomycin C Application. J Ophthalmic Vis Res 2018;13(2):200-202.Abstract
Purpose: To report a surgical approach combining scleral patch graft and tenonplasty for successful management of refractory Pseudomonas scleritis following pterygium removal with mitomycin C application. Case Report: A 75-year-old diabetic woman with a history of prior pterygium excision and mitomycin C application developed infectious necrotizing scleritis caused by . Owing to progression of scleritis despite medical management, the patient underwent surgery. Intraoperatively, extensive scleral ischemia was noted. Therefore, debridement of the necrotic tissue, scleral graft, tenonplasty to bring blood vessels to the ischemic sclera, and amniotic membrane transplantation were performed. Postoperatively, no signs of ischemia or recurrence of infection were observed. During 6 months of follow-up, the patient achieved complete restoration of the globe integrity with a non-inflamed ocular surface. Conclusion: Through restoration of blood supply to the ischemic sclera, tenonplasty is an effective adjunctive procedure in addition to conventional scleral patch graft for the treatment of refractory Pseudomonas scleritis associated with ischemia.
Brown L, Foulsham W, Pronin S, Tatham AJ. The Influence of Corneal Biomechanical Properties on Intraocular Pressure Measurements Using a Rebound Self-tonometer. J Glaucoma 2018;Abstract
PURPOSE: To examine the effect of corneal biomechanical properties on intraocular pressure (IOP) measurements obtained using a rebound self-tonometer (Icare HOME) compared to Goldmann applanation tonometry (GAT). METHODS: An observational study of 100 patients with glaucoma or ocular hypertension. All had a comprehensive ophthalmic examination and standard automated perimetry. IOP was assessed by GAT, Icare HOME and Ocular Response Analyzer (ORA), which was also used to assess corneal hysteresis (CH) and corneal resistance factor (CRF). Central corneal thickness (CCT) was recorded. RESULTS: Mean (±standard deviation) IOP measurements were 14.3±3.9▒mmHg and 11.7±4.7▒mmHg using GAT and Icare HOME respectively. Average CCT, CRF and CH were 534.5±37.3▒μm, 9.0±1.7▒mmHg, and 9.4±1.5▒mmHg respectively. The mean difference between Icare HOME and GAT was -2.66±3.13▒mmHg, with 95% limits of agreement of -8.80 to 3.48▒mmHg, however, there was evidence of proportional bias. There was negative correlation between IOP and CH (5.17▒mmHg higher Icare HOME IOP (P=0.041, R=0.029) and 7.23▒mmHg higher GAT IOP (P=0.008, R=0.080) for each 10▒mmHg lower CH), while thinner CCT was significantly associated with lower IOP (P<0.001, R=0.14 for Icare HOME and P<0.001, R=0.08 for GAT). In multivariable analysis, although CRF and CH remained associated with IOP measured using either GAT or ICare HOME, CCT was no longer significant. CONCLUSIONS: IOP measurements obtained using a self-tonometer, similar to GAT, were more influenced by overall corneal biomechanics than central corneal thickness.
Guhan S, Peng S-L, Janbatian H, Saadeh S, Greenstein S, Al Bahrani F, Fadlallah A, Yeh T-C, Melki SA. Surgical adhesives in ophthalmology: history and current trends. Br J Ophthalmol 2018;Abstract
Tissue adhesives are gaining popularity in ophthalmology, as they could potentially reduce the complications associated with current surgical methods. An ideal tissue adhesive should have superior tensile strength, be non-toxic and anti-inflammatory, improve efficiency and be cost-effective. Both synthetic and biological glues are available. The primary synthetic glues include cyanoacrylate and the recently introduced polyethylene glycol (PEG) derivatives, while most biological glues are composed of fibrin. Cyanoacrylate has a high tensile strength, but rapidly polymerises upon contact with any fluid and has been associated with histotoxicity. Fibrin induces less toxic and inflammatory reactions, and its polymerisation time can be controlled. Tensile strength studies have shown that fibrin is not as strong as cyanoacrylate. While more research is needed, PEG variants currently appear to have the most promise. These glues are non-toxic, strong and time-effective. Through MEDLINE and internet searches, this paper presents a systematic review of the current applications of surgical adhesives to corneal, glaucoma, retinal, cataract and strabismus surgeries. Our review suggests that surgical adhesives have promise to reduce problems in current ophthalmic surgical procedures.
Yin J, Kheirkhah A, Dohlman T, Saboo U, Dana R. Reduced Efficacy of Low-dose Topical Steroids in Dry Eye Disease Associated with Graft-versus-host Disease. Am J Ophthalmol 2018;Abstract
PURPOSE: To compare the response of dry eye disease (DED) to treatment with topical steroid in patients with and without graft-versus-host disease (GVHD). DESIGN: Post-hoc analysis of a double-masked, randomized clinical trial. METHODS: This single-center study included 42 patients with moderate to severe DED associated with (N=21) or without (N=21) chronic GVHD. In each group, patients received either loteprednol etabonate 0.5% ophthalmic suspension or artificial tears twice daily for 4 weeks. Clinical data, including Ocular Surface Disease Index (OSDI) questionnaire, corneal fluorescein staining (CFS), conjunctival lissamine green staining, tear break-up time (TBUT), and Schirmer's test, were evaluated before and after treatment. RESULTS: There were no significant differences in signs and symptoms of DED between the groups at baseline. In non-GVHD patients receiving loteprednol treatment, the average OSDI score decreased by 34% from 49.5 ± 5.9 to 32.6 ± 4.8 (Mean±SEM, P=0.001) and the average CFS score decreased by 41% from 5.6 ± 0.6 to 3.3 ± 0.9 (P=0.02). On the other hand, loteprednol treatment in GVHD patients resulted in minimal change in OSDI (59.2±6.7 to 61.1±7.1, 3% increase, P=0.66) and CFS (5.5±0.5 to 5.3±1.1, 4% decrease, P=0.85) scores. Treatment with artificial tears resulted in 22% decrease of OSDI (P=0.10) and 32% decrease of CFS (P=0.02) scores in non-GVHD patients, and had minimal effect in patients with GVHD. CONCLUSIONS: DED patient with ocular GVHD have a less favorable response to a low-dose topical steroid regimen compared with those without ocular GVHD even with similar baseline disease severity.
Rubinfeld RS, Stulting DR, Gum GG, Talamo JH. Quantitative analysis of corneal stromal riboflavin concentration without epithelial removal. J Cataract Refract Surg 2018;44(2):237-242.Abstract
PURPOSE: To compare the corneal stromal riboflavin concentration and distribution using 2 transepithelial corneal crosslinking (CXL) systems. SETTING: Absorption Systems, San Diego, California, USA. DESIGN: Experimental study. METHODS: The stromal riboflavin concentration of 2 transepithelial CXL systems was compared in rabbit eyes in vivo. The systems were the Paracel/Vibex Xtra, comprising riboflavin 0.25% solution containing TRIS and ethylenediaminetetraacetic acid and an isotonic solution of riboflavin 0.25%, (Group 1) and the CXLO system (Group 2). Manufacturers' Instructions For Use were followed. The intensity of riboflavin fluorescence by slitlamp observation 10, 15, and 20 minutes after instillation was graded on a scale of 0 to 5. The animals were humanely killed and the corneal stromal samples analyzed with liquid chromatography and mass spectrometry. RESULTS: The mean riboflavin fluorescence intensity grades in Group 1 (4 eyes) were 3.8, 4.8, and 4.8 at 10, 15, and 20 minutes, respectively. The mean grades in Group 2 (3 eyes) were 2.0, 2.3, and 2.0, respectively. The riboflavin distribution was uniform in Group 1 but not in Group 2. The mean riboflavin concentration by liquid chromatography and mass spectrometry was 27.0 μg/g stromal tissue in Group 1 and 6.7 μg/g in Group 2. A stromal riboflavin concentration theoretically adequate for CXL, 15 μg/g, was achieved in all eyes in Group 1 and no eyes in Group 2. Slitlamp grading correlated well with liquid chromatography and mass spectrometry concentration (R = 0.940). CONCLUSIONS: The system used in Group 1 produced corneal riboflavin concentrations that were theoretically adequate for effective transepithelial CXL (≥15 μg/g), while the system in Group 2 did not. Slitlamp grading successfully estimated the corneal riboflavin concentration and can be used to ensure an adequate concentration of riboflavin in the cornea for transepithelial CXL.

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