Cornea

Cornea Publications

Argüeso P. Galectins as Regulators of Corneal Inflammation. Curr Opin Physiol 2021;19:17-21.Abstract
The cornea is a transparent avascular tissue on the anterior segment of the eye responsible for providing refractive power and forming a protective barrier against the external environment. Infectious and inflammatory conditions can compromise the structure of the cornea, leading to visual impairment and blindness. Galectins are a group of β-galactoside-binding proteins expressed by immune and non-immune cells that play pivotal roles in innate and adaptive immunity. In this brief review, we discuss how different members of this family of proteins affect both pro-inflammatory and anti-inflammatory responses in the cornea, particularly in the context of infection, transplantation and wound healing. We further describe recent research showing beneficial effects of galectin-targeted therapy in corneal diseases.
Chirapapaisan C, Muller RT, Sahin A, Cruzat A, Cavalcanti BM, Jamali A, Pavan-Langston D, Hamrah P. Effect of herpes simplex keratitis scar location on bilateral corneal nerve alterations: an in vivo confocal microscopy study. Br J Ophthalmol 2020;Abstract
AIMS: To evaluate the impact of herpes simplex virus (HSV)-induced scar location on bilateral corneal nerve alterations using laser in vivo confocal microscopy (IVCM). METHODS: Central and peripheral corneal subbasal nerve density (CSND) were assessed bilaterally in 39 patients with unilateral HSV-induced corneal scars (21 central scars (CS), 18 peripheral scars (PS)) using IVCM. Results were compared between patients and 24 age-matched controls. CSND was correlated to corneal sensation for all locations. RESULTS: Overall patients revealed significant decrease of CSND in the central and peripheral cornea (9.13±0.98 and 6.26±0.53 mm/mm, p<0.001), compared with controls (22.60±0.77 and 9.88±0.49 mm/mm). CS group showed a decrease in central (8.09±1.30 mm/mm) and total peripheral nerves (5.15±0.62 mm/mm) of the affected eyes, whereas PS group demonstrated a decrease in central (10.34±1.48 mm/mm) and localised peripheral nerves only in the scar area (4.22±0.77 mm/mm) (all p<0.001). In contralateral eyes, CSND decreased in the central cornea of the CS group (16.88±1.27, p=0.004), and in the peripheral area, mirroring the scar area in the affected eyes of the PS group (7.20±0.87, p=0.032). Corneal sensation significantly decreased in the whole cornea of the affected, but not in contralateral eyes (p<0.001). A positive correlation between CSND and corneal sensation was found in all locations (p<0.001). CONCLUSIONS: Patients with HSV scar demonstrate bilateral CSND decrease as shown by IVCM. CSND and corneal sensation decrease in both central and peripheral cornea in affected eyes, although only in the scar area in PS group. Interestingly, diminishment of CSND was found locally in the contralateral eyes, corresponding and mirroring the scar location in the affected eyes.
Tellefsen S, Badian RA, Utheim TP, Utheim ØA, Stojanovic A, Tashbayev B, Raeder S, Dartt DA, Chen X. Sex and age differences in symptoms and signs of dry eye disease in a Norwegian cohort of patients. Ocul Surf 2020;Abstract
PURPOSE: To investigate sex and age differences in symptoms and signs in a Norwegian clinic-based cohort of patients with dry eye disease (DED). METHODS: Visitors at the Norwegian Dry Eye Clinic were examined using Ocular Surface Disease Index (OSDI) questionnaire score, tear osmolarity, tear break-up time (TFBUT), ocular surface staining, corneal sensitivity, Schirmer I test, and meibum expressibility (ME) and quality (MQ). A diagnosis of DED was made by an ophthalmologist based on symptoms and signs, and only DED patients were enrolled in the study: 1823 patients (338 males; mean age 51.2 ± 16.2 years; 1485 females; mean age 52.5 ± 16.0 years). The patients were divided into age subgroups: 20-39 years, 40-59 years and ≥60 years. Sex differences in the aforementioned tests were analyzed. Values were reported as mean ± standard deviation (SD), and intergroup comparisons were performed using Mann-Whitney U test. Multiple regression was used to analyze sex and age influences on symptoms and signs. RESULTS: When patients of all ages were analyzed, females had increased osmolarity, shorter TFBUT, reduced MQ and ME and higher corneal sensitivity. OSDI, Schirmer I test, ocular surface staining and corneal staining were not significantly different between the sexes. Only with TFBUT and ME were the sex difference present in all age subgroups. Multiple regression showed that all parameters were influenced by either sex or age, but only TFBUT and ME were influenced by both sex and age. (all p < 0.05). CONCLUSIONS: Sex and age differences in dry eye were most consistent in TFBUT and ME, that indicate differences in meibomian gland functionality. Sex and age subgroup stratification is important in future studies investigating DED in other populations.
Hui P-C, Pereira LA, Dore R, Chen S, Taniguchi E, Chodosh J, Dohlman CH, Paschalis EI. Intrinsic Optical Properties of Boston Keratoprosthesis. Transl Vis Sci Technol 2020;9(12):10.Abstract
Purpose: To benchmark the optical performance of Boston Keratoprosthesis (B-KPro). Methods: Back focal lengths (BFL) of B-KPros for various eye axial lengths were measured using an optical bench, International Organization for Standardization-certified for intraocular lens characterization, and compared against manufacturer's specification. The modulation transfer function (MTF) and the resolution efficiencies were measured. The theoretical geometry-dependent higher-order aberrations (HOA) were calculated. The devices were characterized with optical profilometry for estimating the surface scattering. Aberration correction and subsequent image quality improvement were simulated in CODE-V. Natural scene-imaging was performed in a mock ocular environment. Retrospective analysis of 15 B-KPro recipient eyes were presented to evaluate the possibility of achieving 20/20 best-corrected visual acuity (BCVA). Results: BFL measurements were in excellent agreement with the manufacturer-reported values (r = 0.999). The MTF specification exceeded what is required for achieving 20/20 visual acuity. Astigmatism and field curvature, correctable in simulations, were the primary aberrations limiting imaging performance. Profilometry of the anterior surface revealed nanoscale roughness (root-mean-square amplitude, 30-50 nm), contributing negligibly to optical scattering. Images of natural scenes obtained with a simulated B-KPro eye demonstrated good central vision, with 10/10 visual acuity (equivalent to 20/20). Full restoration of 20/20 BCVA was obtainable for over 9 years in some patients. Conclusions: Theoretical and experimental considerations demonstrate that B-KPro has the optical capacity to restore 20/20 BCVA in patients. Further image quality improvement can be anticipated through correction of HOAs. Translational Relevance: We establish an objective benchmark to characterize the optics of the B-KPro and other keratoprosthesis and propose design changes to allow improved vision in B-KPro patients.
Venkateswaran N, Klavdianou O, Kondylis G, Kosmidis I, Palioura S. Paraneoplastic Pemphigus Associated with Bilateral Corneal Perforations in Follicular Dendritic Cell Sarcoma. Ocul Immunol Inflamm 2020;:1-3.Abstract
PURPOSE: To describe a case of paraneoplastic pemphigus (PNP) presenting as spontaneous bilateral corneal perforations in a patient with follicular dendritic cell sarcoma. METHODS: Retrospective chart review Results: A 73-year-old Greek woman with a history of follicular dendritic cell sarcoma (FDCS) presented with bilateral corneal perforations and a cicatrizing conjunctivitis. Her diagnosis was consistent with PNP with corneal and conjunctival involvement after a change in her chemotherapy regimen from intravenous cyclophosphamide to gemcitabine. She was treated with a multilayered amniotic membrane in the right eye and cyanoacrylate glue in the left eye. Systemic intravenous cyclophosphamide and oral prednisone were re-started. Both perforations healed but the patient passed away soon after precluding further follow-up. CONCLUSIONS: Ocular manifestations of PNP can rarely present with spontaneous corneal perforations. This is the first case of FDCS-associated PNP with corneal involvement. Such cases should be diagnosed expediently and managed with aggressive systemic immunosuppressive therapy.
Ramier A, Eltony AM, Chen YT, Clouser F, Birkenfeld JS, Watts A, Yun S-H. In vivo measurement of shear modulus of the human cornea using optical coherence elastography. Sci Rep 2020;10(1):17366.Abstract
Corneal stiffness plays a critical role in shaping the cornea with respect to intraocular pressure and physical interventions. However, it remains difficult to measure the mechanical properties noninvasively. Here, we report the first measurement of shear modulus in human corneas in vivo using optical coherence elastography (OCE) based on surface elastic waves. In a pilot study of 12 healthy subjects aged between 25 and 67, the Rayleigh-wave speed was 7.86 ± 0.75 m/s, corresponding to a shear modulus of 72 ± 14 kPa. Our data reveal two unexpected trends: no correlation was found between the wave speed and IOP between 13-18 mmHg, and shear modulus decreases with age (- 0.32 ± 0.17 m/s per decade). We propose that shear stiffness is governed by the interfibrillar matrix, whereas tensile strength is dominated by collagen fibrils. Rayleigh-wave OCE may prove useful for clinical diagnosis, refractive surgeries, and treatment monitoring.
Latifi G, Banafshe Afshan A, Houshang Beheshtnejad A, Zarei-Ghanavati M, Mohammadi N, Ghaffari R, Ghassemi H, Mohammadi SS, Kheirkhah A. Changes in Corneal Subbasal Nerves after Punctal Occlusion in Dry Eye Disease. Curr Eye Res 2020;:1-7.Abstract
PURPOSE: To evaluate corneal subbasal nerve plexus by in vivo confocal microscopy (IVCM) following punctal occlusion in patients with moderate to severe dry eye disease (DED). MATERIALS AND METHODS: Patients with grade 3 or 4 severity of DED based on Delphi Panel dry eye severity grading scheme were enrolled in the study. Permanent inferior punctal occlusion was performed. A comprehensive ophthalmic evaluation, including Ocular Surface Disease Index (OSDI) questionnaire, tear break-up time (TBUT), corneal fluorescein staining, conjunctival Rose bengal staining, Schirmer's test, and corneal sensation by Cochet-Bonnet esthesiometry, were performed at baseline, and 1 and 3 months after punctal occlusion. Furthermore, density and number of corneal subbasal nerves were evaluated by IVCM. RESULTS: Forty-one eyes of 23 patients with a mean age of 46.3 ± 9.0 years were enrolled. Corneal fluorescein staining, Rose bengal staining, and TBUT significantly improved at 3 months following punctal occlusion ( < .015). Corneal esthesiometry significantly increased at both postoperative visits ( < .03), and OSDI scores improved only at 3-month follow-up ( < .005). Nerve density and total number significantly increased 3 months after punctal occlusion ( < .045). Baseline nerve density had significant correlations with TBUT, fluorescein staining, Rose bengal staining ( < .012), but not with esthesiometry, Schirmer scores, or OSDI scores ( > .329). CONCLUSIONS: Corneal subbasal nerve density and total number increased following punctal occlusion in patients with moderate to severe DED. These findings were associated with improvements in corneal sensation, and signs and symptoms of DED. This emphasizes the effect of punctal occlusion in regeneration of corneal subbasal nerve plexus.
Carreno-Galeano JT, Dohlman TH, Yin J, Dana R. Limbal Stem Cell Deficiency Associated With Herpes Keratitis. Cornea 2020;Abstract
PURPOSE: To describe the demographic features and clinical characteristics of patients with herpes keratitis (HK) and limbal stem cell deficiency (LSCD) and identify possible factors associated with development of LSCD after HK. METHODS: In this retrospective case-series study, records of patients with a clinical diagnosis of HK seen at Massachusetts Eye and Ear over a 5-year period were reviewed for evidence of LSCD. Patient demographics, medical history, treatment, and best-corrected visual acuities (BCVAs) were recorded. RESULTS: We identified 626 patients with HK. Fifty-seven had been diagnosed with LSCD (9.3%). Thirteen percent of patients with herpes zoster keratitis (N= 25) and 7% of patients with herpes simplex keratitis (N= 32) had LSCD (P = 0.01). Keratitis caused by herpes zoster virus [odds ratios (OR), 1.77; 95% confidence interval (CI), 0.97-3.19; P = 0.01], stromal involvement (OR, 2.28; 95% CI, 1.27-4.18; P = 0.02), and the use of topical antihypertensives (OR, 2.28; 95% CI, 1.27-4.18; P = 0.02) were found to be associated with a higher likelihood of developing LSCD. The final logarithm of the minimum angle of resolution (LogMAR) BCVA was significantly lower in patients with LSCD compared with those without LSCD with a mean BCVA of 1.34 ± 1.52 LogMar (∼20/200) as compared to 0.18 ± 0.54 LogMar (∼20/30 ± 20/60) in those patients without LSCD (P = 0.005). CONCLUSIONS: Our data suggest that HK may be a risk factor for development of LSCD. Patients with HK should be monitored for the development of LSCD to reduce the risk of chronic ocular surface morbidity.
Hayashi T, Yasutsugu I, Shimizu T, Kuroki T, Kobashigawa Y, Iijima Y, Yuda K. Pars plana vitrectomy combined with penetrating keratoplasty and transscleral-sutured intraocular lens implantation in complex eyes: a case series. BMC Ophthalmol 2020;20(1):369.Abstract
BACKGROUND: The aim of this study was to evaluate the clinical outcomes of pars plana vitrectomy (PPV) combined with penetrating keratoplasty (PKP) and transscleral-sutured intraocular lens (IOL) implantation (IOL-suture) in complex eyes. METHODS: In this prospective, consecutive interventional case series, patients who underwent PKP combined with PPV and IOL implantation from July 2014 to March 2018 at Yokohama Minami Kyosai Hospital were enrolled. The postoperative best corrected visual acuity (BCVA) (converted to logarithm of the minimal angle of resolution [logMAR] units), intraocular pressure (IOP, mmHg), endothelial cell density (ECD, cells/mm), graft survival, complications, astigmatism, and spherical equivalent (dioptres [D]) were evaluated. RESULTS: This study included 11 eyes of 11 patients (three females and eight males; mean age, 61.8 ± 13.9 years) with an injury (n = 6) or bullous keratopathy (n = 5). The BCVA significantly improved from 1.50 ± 0.66 logMAR preoperatively to 0.78 ± 0.59 logMAR (p < 0.001) postoperatively. The baseline ECD significantly decreased from 2396 ± 238 cells/mm preoperatively to 1132 ± 323 cells/mm (p < 0.001) postoperatively. Despite two rejection episodes, graft survival rates were 100%. The mean follow-up period was 38.0 ± 20.5 months. Two patients required combined glaucoma surgery, and three patients underwent subsequent glaucoma surgery. Postoperative astigmatism and spherical equivalent were 3.9 ± 3.2 D and 0.29 ± 2.18 D, respectively. CONCLUSION: The combination of PKP, PPV, and IOL-suture implantation could be a safe and effective approach for eyes requiring anterior segment surgery; however, these eyes are associated with a higher incidence of glaucoma surgery.
Chen D, Wang J, Sullivan DA, Kam WR, Liu Y. Effects of Terpinen-4-ol on Meibomian Gland Epithelial Cells In Vitro. Cornea 2020;Abstract
PURPOSE: Infestation with demodex mites has been linked to the development of chalazion, meibomian gland dysfunction, and blepharitis. An effective treatment is the eyelid application of terpinen-4-ol (T4O), a tea tree oil component. However, T4O is also known to be toxic to nonocular epithelial cells. We hypothesize that T4O toxicity also extends to human meibomian gland epithelial cells (HMGECs). METHODS: Immortalized (I) HMGECs were cultured with varying concentrations (1.0%-0.001%) of T4O under proliferating or differentiating conditions up to 5 days. Experimental procedures included analyses of cell appearance, survival, P-Akt signaling, lysosome accumulation, and neutral lipid content. RESULTS: Our findings show that T4O causes a dose- and time-dependent decrease in the cell survival of IHMGECs. After 15 minutes of exposure to 1% T4O, IHMGECs exhibited rounding, atrophy, and poor adherence. Within 90 minutes of such treatment, almost all cells died. Reducing the T4O concentration to 0.1% also led to a marked decrease in P-Akt signaling and cell survival of IHMGECs. Decreasing the T4O amount to 0.01% caused a slight, but significant, reduction in the IHMGEC number after 5 days of culture and did not influence the ability of these cells to differentiate. CONCLUSIONS: T4O, even at levels 10-fold to 100-fold lower than demodicidal concentrations, is toxic to HMGECs in vitro.
Lužnik Z, Sun Z, Nakagawa H, Taylor AW, Jurkunas UV, Yin J, Dana R. Association of α-Melanocyte-Stimulating Hormone With Corneal Endothelial Cell Survival During Oxidative Stress and Inflammation-Induced Cell Loss in Donor Tissue. JAMA Ophthalmol 2020;Abstract
Importance: Corneal endothelial cell (CEnC) damage and loss are major issues in eye banking and transplantation. The underlying mechanisms for CEnC loss are incompletely understood, and cytoprotective strategies that enhance CEnC viability could have a major effect on donor tissue quality and graft survival. Objective: To investigate the cytoprotective role of neuropeptide α-melanocyte-stimulating hormone (α-MSH) in preventing CEnC loss in eye bank cold-stored corneas under oxidative and inflammatory cytokine-induced stress. Design, Setting, and Participants: This single-center comparative research study conducted ex vivo experiments using 16 pairs of research-grade human donor corneas (courtesy of Eversight Eye Bank). Data were collected from June 2018 to November 2019, and data were analyzed from December 2019 to January 2020. Exposures: Two corneas from the same donor were randomized to either control or 0.1 mmol/L of α-MSH treatment and then subjected to oxidative stress (1.4 mmol/L of hydrogen peroxide-phosphate-buffered saline for 15 minutes at 37 °C; n = 8 pairs) or cytokine-induced stress (100 ng/mL of tumor necrosis factor-α and 100 ng/mL of interferon γ for 18 hours at 37 °C; n = 8 pairs). Corneas were then stored at 4 °C. Specular images were taken at baseline and repeated twice per week using a calibrated wide-field specular microscope. CEnC viability was assessed using a fluorescent live/dead viability assay. Main Outcome and Measures: Endothelial morphometry analysis, central corneal thickness measurements, and percentage of dead cells at day 11. Results: Of 16 donors who provided corneas, 9 (56%) were male, and the mean (SD) age was 57.9 (12.4) years. Corneas were paired, and baseline parameters were comparable between all groups. At all time points, CEnC loss was lower in the α-MSH groups compared with the control groups. This difference was statistically significant after cytokine-induced stress (20.2% vs 35.2%; sample estimate of median, -14.9; 95% CI, -23.6 to -6.3; P = .008). Compared with the control group, α-MSH treatment resulted in a smaller increase in central corneal thickness (cytokine-induced stress: 89.3 μm vs 169.8 μm; sample estimate of median, -84.9; 95% CI, -131.5 to -41.6; P = .008; oxidative stress: 43.6 μm vs 111.9 μm; sample estimate of median, -68.8; 95% CI, -100.0 to -34.5; P = .008) and a smaller proportion of cell death (cytokine-induced stress: 2.7% vs 10.4%; difference, -7.7; 95% CI, -13.1 to -2.4; P = .01; oxidative stress: 2.9% vs 12.4%; difference, 9.5; 95% CI, 5.1 to 13.9; P = .006). Conclusions and Relevance: In this study, α-MSH treatment attenuated CEnC loss during cold storage after acute oxidative and cytokine-induced stress in human eye bank cold-stored corneas. These data suggest that supplementation of corneal storage solution with α-MSH may positively affect CEnC survival after transplant and protect the endothelium from proinflammatory cytokines and oxidative stress after full-thickness or endothelial keratoplasty, which is particularly valuable in patients at high risk of graft failure.
Daniel S, Renwick M, Chau VQ, Datta S, Maddineni P, Zode G, Wade EM, Robertson SP, Petroll MW, Hulleman JD. Fibulin-3 knockout mice demonstrate corneal dysfunction but maintain normal retinal integrity. J Mol Med (Berl) 2020;98(11):1639-1656.Abstract
Fibulin-3 (F3) is an extracellular matrix glycoprotein found in basement membranes across the body. An autosomal dominant R345W mutation in F3 causes a macular dystrophy resembling dry age-related macular degeneration (AMD), whereas genetic removal of wild-type (WT) F3 protects mice from sub-retinal pigment epithelium (RPE) deposit formation. These observations suggest that F3 is a protein which can regulate pathogenic sub-RPE deposit formation in the eye. Yet the precise role of WT F3 within the eye is still largely unknown. We found that F3 is expressed throughout the mouse eye (cornea, trabecular meshwork (TM) ring, neural retina, RPE/choroid, and optic nerve). We next performed a thorough structural and functional characterization of each of these tissues in WT and homozygous (F3) knockout mice. The corneal stroma in F3 mice progressively thins beginning at 2 months, and the development of corneal opacity and vascularization starts at 9 months, which worsens with age. However, in all other tissues (TM, neural retina, RPE, and optic nerve), gross structural anatomy and functionality were similar across WT and F3 mice when evaluated using SD-OCT, histological analyses, electron microscopy, scotopic electroretinogram, optokinetic response, and axonal anterograde transport. The lack of noticeable retinal abnormalities in F3 mice was confirmed in a human patient with biallelic loss-of-function mutations in F3. These data suggest that (i) F3 is important for maintaining the structural integrity of the cornea, (ii) absence of F3 does not affect the structure or function of any other ocular tissue in which it is expressed, and (iii) targeted silencing of F3 in the retina and/or RPE will likely be well-tolerated, serving as a safe therapeutic strategy for reducing sub-RPE deposit formation in disease. KEY MESSAGES: • Fibulins are expressed throughout the body at varying levels. • Fibulin-3 has a tissue-specific pattern of expression within the eye. • Lack of fibulin-3 leads to structural deformities in the cornea. • The retina and RPE remain structurally and functionally healthy in the absence of fibulin-3 in both mice and humans.
Taketani Y, Marmalidou A, Dohlman TH, Singh RB, Amouzegar A, Chauhan SK, Chen Y, Dana R. Restoration of Regulatory T-Cell Function in Dry Eye Disease by Antagonizing Substance P/Neurokinin-1 Receptor. Am J Pathol 2020;190(9):1859-1866.Abstract
Substance P (SP) is a tachykinin neuropeptide, implicated in the pathogenesis of various inflammatory conditions and a critical mediator in pain transmission. Recently, the role of SP was described in the pathogenesis of dry eye disease (DED) through its role in the maturation of antigen-presenting cells at the ocular surface after exposure to desiccating stress. However, the effect of SP on regulatory T cells (Tregs), which are functionally impaired in DED, remains unclear. This study examined the phenotypic and functional changes in Tregs in response to SP in DED. The in vitro cultures of normal Tregs in the presence of SP led to a significant reduction in both Treg frequencies and their suppressive function, which was prevented by the addition of an SP receptor (neurokinin-1 receptor) antagonist. Furthermore, in vivo treatment with the neurokinin-1 receptor antagonist in DED mice effectively restored Treg function, suppressed pathogenic T helper 17 response, and significantly ameliorated the disease. Our results show that a significant increase in SP levels promotes Treg dysfunction in DED, and blockade of SP effectively restores Treg function and suppresses DED severity.
Jamali A, Hu K, Sendra VG, Blanco T, Lopez MJ, Ortiz G, Qazi Y, Zheng L, Turhan A, Harris DL, Hamrah P. Characterization of Resident Corneal Plasmacytoid Dendritic Cells and Their Pivotal Role in Herpes Simplex Keratitis. Cell Rep 2020;32(9):108099.Abstract
The presence and potential functions of resident plasmacytoid dendritic cells (pDCs) in peripheral tissues is unclear. We report that pDCs constitutively populate naïve corneas and are increased during sterile injuries or acute herpes simplex virus 1 (HSV-1) keratitis. Their local depletion leads to severe clinical disease, nerve loss, viral dissemination to the trigeminal ganglion and draining lymph nodes, and mortality, while their local adoptive transfer limits disease. pDCs are the main source of HSV-1-induced IFN-α in the corneal stroma through TLR9, and they prevent re-programming of regulatory T cells (Tregs) to effector ex-Tregs. Clinical signs of infection are observed in pDC-depleted corneas, but not in pDC-sufficient corneas, following low-dose HSV-1 inoculation, suggesting their critical role in corneal antiviral immunity. Our findings demonstrate a vital role for corneal pDCs in the control of local viral infections.

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