January 2018

Carvalho LS, Xiao R, Wassmer S, Langsdorf A, Zinn E, Pacouret S, Shah S, Comander JI, Kim L, Lim L, Vandenberghe LH. Synthetic adeno-associated viral vector efficiently targets mouse and non-human primate retina in vivo. Hum Gene Ther 2018;Abstract
Gene therapy is a promising approach in the treatment of inherited and common complex disorders of the retina. Preclinical and clinical studies have validated the use of adeno-associated viral vectors (AAV) as a safe and efficient delivery vehicle for gene transfer. RPE and rods, and to a lesser extent, cone photoreceptors can be efficiently targeted with AAV. Other retinal cell types however are more challenging targets. The aim of this study was to characterize the transduction profile and efficiency of in silico designed, synthetic Anc80 AAVs for retinal gene transfer. Three Anc80 variants were evaluated for retinal targeting in mice and primates following subretinal delivery. In the murine retina Anc80L65 demonstrated high level of RPE and photoreceptor targeting with comparable cone photoreceptor affinity compared to other AAVs. Remarkably, Anc80L65 enhanced transduction kinetics with visible expression as early as day 1 and steady state mRNA levels at day 3. Inner retinal tropism of Anc80 variants demonstrated distinct transduction patterns of Müller glia, retinal ganglion cells and INL neurons. Finally, murine findings with Anc80L65 qualitatively translated to the Rhesus macaque in terms of cell targets, levels and onset of expression. Our findings support the use of Anc80L65 for therapeutic subretinal gene delivery.
Cavalcanti BM, Cruzat A, Sahin A, Pavan-Langston D, Samayoa E, Hamrah P. In vivo confocal microscopy detects bilateral changes of corneal immune cells and nerves in unilateral herpes zoster ophthalmicus. Ocul Surf 2018;16(1):101-111.Abstract
PURPOSE: To analyze bilateral corneal immune cell and nerve alterations in patients with unilateral herpes zoster ophthalmicus (HZO) by laser in vivo confocal microscopy (IVCM) and their correlation with corneal sensation and clinical findings. MATERIALS AND METHODS: This is a prospective, cross-sectional, controlled, single-center study. Twenty-four eyes of 24 HZO patients and their contralateral clinically unaffected eyes and normal controls (n = 24) were included. Laser IVCM (Heidelberg Retina Tomograph/Rostock Cornea Module), corneal esthesiometry (Cochet-Bonnet) were performed. Changes in corneal dendritiform cell (DC) density and morphology, number and length of subbasal nerve fibers and their correlation to corneal sensation, pain, lesion location, disease duration, and number of episodes were analyzed. RESULTS: HZO-affected and contralateral eyes showed a significant increase in DC influx of the central cornea as compared to controls (147.4 ± 33.9, 120.1 ± 21.2, and 23.0 ± 3.6 cells/mm2; p < 0.0001). In HZO eyes DCs were larger in area (319.4 ± 59.8 μm2; p < 0.001) and number of dendrites (3.5 ± 0.4 n/cell; p = 0.01) as compared to controls (52.2 ± 11.7, and 2.3 ± 0.5). DC density and size showed moderate negative correlation with total nerve length (R = -0.43 and R = -0.57, respectively; all p < 0.001). A higher frequency of nerve beading and activated DCs close to nerve fibers were detected specifically in pain patients. CONCLUSIONS: Chronic unilateral HZO causes significant bilateral increase in corneal DC density and decrease of the corneal subbasal nerves as compared to controls. Negative correlation was observed for DC density and size to nerve parameters, suggesting interplay between the immune and nervous systems. Patients with chronic pain also showed increased nerve beading and activated DCs.
Cestari DM, Cunnane ME, Rizzo JF, Stone JH. Case 2-2018. A 41-Year-Old Woman with Vision Disturbances and Headache. N Engl J Med 2018;378(3):282-289.
Chen CL, Clay TH, McLeod S, Peggy Chang H-Y, Gelb AW, Dudley AR. A Revised Estimate of Costs Associated With Routine Preoperative Testing in Medicare Cataract Patients With a Procedure-Specific Indicator. JAMA Ophthalmol 2018;Abstract
Importance: Routine preoperative medical testing is not recommended for patients undergoing low-risk surgery, but testing is common before surgery. A 30-day preoperative testing window is conventionally used for study purposes; however, the extent of routine testing that occurs prior to that point is unknown. Objective: To improve on existing cost estimates by identifying all routine preoperative testing that takes place after the decision is made to perform cataract surgery. Design, Setting, and Participants: This cross-sectional study assessed preoperative care in a 50% sample of Medicare beneficiaries older than 66 years who underwent ambulatory cataract surgery in 2011. Data analysis was completed from March 2016 to October 2017. Main Outcomes and Measures: Using ocular biometry as a procedure-specific indicator to mark the start of the routine preoperative testing window, we measured testing rates in the interval between ocular biometry and cataract surgery and compared this with testing rates in the 6 months preceding biometry. We estimated the total cost of testing that occurred between biometry and cataract surgery. Results: A total of 440 857 patients underwent cataract surgery. A total of 423 710 (96.1%) had an ocular biometry claim before index surgery, of whom 264 514 (60.0%) were female; the mean (SD) age of the cohort was 76.1 (6.2) years. A total of 111 998 (25.4%) underwent surgery more than 30 days after biometry. Among patients with a biometry claim, the mean number of tests/patient/month increased from 1.1 in the baseline period to 1.7 in the interval between biometry and cataract surgery. Although preoperative testing peaked in all patients in the 30 days preceding surgery (1.8 tests/patient/month), the subset of patients with no overlap between postbiometry and presurgery periods experienced increased testing rates to 1.8 tests per patient per month in the 30 days after biometry, regardless of the elapsed time between biometry and surgery. The total estimated cost of routine preoperative testing in the full cohort was $22.7 million; we estimate that routine preoperative testing costs Medicare up to $45.4 million annually. Conclusions and Relevance: In this study of Medicare beneficiaries, routine preoperative medical testing occurs more often and is costlier than has been reported previously. Extra costs are attributable to testing that occurs prior to the 30-day window preceding surgery. As a cost-cutting measure, routine preoperative medical testing should be avoided in patients with cataracts throughout the interval between ocular biometry and cataract surgery.
Choi HJ, Wang R, Jakobs TC. Single-Cell Dissociation and Characterization in the Murine Retina and Optic Nerve. Methods Mol Biol 2018;1695:311-334.Abstract
Recent technological advances have extended the range of analytic tools to very small samples. It is now possible to assay the transcriptome, and in some cases even the proteome, of single cells reliably. This allows addressing novel questions, such as the genotype/phenotype relationships of single neurons, heterogeneity within individual cells of the same type, or the basis of differential vulnerability to injury. An important prerequisite for these kinds of studies is the ability to isolate well-defined individual cells without contamination by adjacent tissue. In the retina and optic nerve, cells of different types and functions are closely intermingled, limiting the use of standard methods such as laser capture microdissection. Here, we describe a simple method to isolate morphologically intact cells from the retina and the optic nerve and discuss considerations in recognizing and isolating different cell types after dissociation.
Chuck RS, Jacobs DS, Lee JK, Afshari NA, Vitale S, Shen TT, Keenan JD, of Panel AAOPPPRM/I. Refractive Errors & Refractive Surgery Preferred Practice Pattern®. Ophthalmology 2018;125(1):P1-P104.
Cruzat A, Gonzalez-Andrades M, Mauris J, AbuSamra DB, Chidambaram P, Kenyon KR, Chodosh J, Dohlman CH, Argüeso P. Colocalization of Galectin-3 With CD147 Is Associated With Increased Gelatinolytic Activity in Ulcerating Human Corneas. Invest Ophthalmol Vis Sci 2018;59(1):223-230.Abstract
Purpose: Galectin-3 is a carbohydrate-binding protein known to promote expression of matrix metalloproteinases, a hallmark of ulceration, through interaction with the extracellular matrix metalloproteinase inducer CD147. The aim of this study was to investigate the distribution of galectin-3 in corneas of patients with ulcerative keratitis and to determine its relationship to CD147 and the presence of gelatinolytic activity. Methods: This was an observational case series involving donor tissue from 13 patients with active corneal ulceration and 6 control corneas. Fixed-frozen sections of the corneas were processed to localize galectin-3 and CD147 by immunofluorescence microscopy. Gelatinolytic activity was detected by in situ zymography. Results: Tissue from patients with active corneal ulceration showed a greater galectin-3 immunoreactivity in basal epithelia and stroma compared with controls. Immunofluorescence grading scores revealed increased colocalization of galectin-3 and CD147 in corneal ulcers at the epithelial-stromal junction and within fibroblasts. Quantitative analysis using the Manders' colocalization coefficient demonstrated significant overlap in corneas from patients with ulcerative keratitis (M1 = 0.29; M2 = 0.22) as opposed to control corneas (M1 = 0.01, P < 0.01; M2 = 0.02, P < 0.05). In these experiments, there was a significant positive correlation between the degree of galectin-3 and CD147 colocalization and the presence of gelatinolytic activity. Conclusions: Our results indicate that concomitant stimulation and colocalization of galectin-3 with CD147 are associated with increased gelatinolytic activity in the actively ulcerating human cornea and suggest a mechanism by which galectin-3 may contribute to the degradation of extracellular matrix proteins during ulceration.
Ebrahimiadib N, Hernandez M, Modjtahedi BS, Roohipoor RC, Foster SC. Atopy in Patients With Ocular Cicatricial Pemphigoid. Cornea 2018;Abstract
PURPOSE: To evaluate the presence of atopy in patients with ocular cicatricial pemphigoid (OCP). METHOD: Patient encounters between August 2005 and November 2016 at the Massachusetts Eye Research and Surgery Institute (MERSI) were searched to identify those with biopsy-proven OCP who had concurrent evidence of atopy. RESULTS: There were 230 patients with biopsy-proven OCP. Thirty-three of them were found to have clinical symptoms of atopy (asthma, hay fever, and eczema) and of these, 23 had evidence of atopy in their conjunctival biopsy specimens. All patients were administered immunomodulatory therapy for treatment of their OCP with 20 patients requiring additional antiallergy treatment to control residual atopic ocular symptoms. Among patients who used antiallergy medications, 80% showed improvement in residual symptoms. Rituximab and/or intravenous immunoglobulin is a preferred OCP medication for patients with OCP with some evidence of atopy. CONCLUSIONS: Clinicians should consider the coexistence of atopy in patients with OCP, especially in those with persistent symptoms after initiation of immunomodulatory therapy.
Eslani M, Putra I, Shen X, Hamouie J, Tadepalli A, Anwar KN, Kink JA, Ghassemi S, Agnihotri G, Reshetylo S, Mashaghi A, Dana R, Hematti P, Djalilian AR. Cornea Derived MSCs Therapeutically Modulate Macrophage Immunophenotype And Angiogenic Function. Stem Cells 2018;Abstract
Macrophages are crucial drivers of inflammatory corneal neovascularization and thus are potential targets for immunomodulatory therapies. We hypothesized that therapeutic use of cornea derived mesenchymal stromal cells (cMSCs) may alter the function of macrophages. We found that cMSCs can modulate the phenotype and angiogenic function of macrophages. In vitro, cMSCs induce apoptosis of macrophages while preferentially promoting a distinct CD14hi CD16hi CD163hi CD206hi immunophenotype that has significantly reduced angiogenic effects based on in vitro angiogenesis assays. In vivo, application of cMSCs to murine corneas after injury leads to reduced macrophage infiltration and higher expression of CD206 in macrophages. Macrophages co-cultured ("educated") by cMSCs express significantly higher levels of anti-angiogenic and anti-inflammatory factors compared to control macrophages. In vivo, injured corneas treated with cMSC-educated macrophages demonstrate significantly less neovascularization compared to corneas treated with control macrophages. Knocking down the expression of PEDF in cMSCs significantly abrogates its modulating effects on macrophages, as shown by the reduced rate of apoptosis, decreased expression of sFLT-1/PEDF, and increased expression of VEGF-A in the co-cultured macrophages. Similarly, cMSCs isolated from PEDF knockout mice are less effective compared to wild type cMSCs at inhibiting macrophage infiltration when applied to wild type corneas after injury. Overall, these results demonstrate that cMSCs therapeutically suppress the angiogenic capacity of macrophages and highlight the role of cMSC secreted PEDF in the modulation of macrophage phenotype and function. This article is protected by copyright. All rights reserved.
Feinstein M, Moussa K, Han Y. Ab Interno Tube Occlusion for Postoperative Hypotony in a Patient with an Ahmed Glaucoma Drainage Device. J Glaucoma 2018;Abstract
PURPOSE: To report a case of Ahmed glaucoma valve-induced hypotony that was successfully managed with postoperative intraluminal stenting of the aqueous shunt tube. PATIENT AND METHODS: We describe a 68-year-old male with advanced uveitic glaucoma with an intraocular pressure (IOP) of 25▒mm Hg in the left eye. The patient initially responded well to an Ahmed glaucoma valve implant, but at 10 weeks post-implantation, the patient underwent cataract surgery and developed persistent hypotony, choroidal folds, and decreased vision. RESULTS: Prior to partial occlusion of the aqueous shunt tube, the patient had an IOP of 3▒mm Hg and a best corrected visual acuity (BCVA) of 20/60. Following intraluminal stenting of the aqueous shunt tube with 4-0 polypropylene suture (Prolene; Ethican), IOP rose to 7-10▒mm Hg, BCVA improved to 20/30, and the choroidal folds resolved; IOP and BCVA remained stable through one-year of follow up and no additional surgical or pharmacological interventions were required. CONCLUSION: Aqueous shunt-induced hypotony can be successfully managed with intraluminal stenting and should be considered before tubal ligation or shunt removal.
Fernandez-Godino R, Bujakowska KM, Pierce EA. Changes in extracellular matrix cause RPE cells to make basal deposits and activate the alternative complement pathway. Hum Mol Genet 2018;27(1):147-159.Abstract
The design of efficient therapies for age-related macular degeneration (AMD) is limited by our understanding of the pathogenesis of basal deposits, which form between retinal pigment epithelium (RPE) and Bruch's membrane (BrM) early in disease, and involve activation of the complement system. To investigate the roles of BrM, RPE and complement in an AMD, we generated abnormal extracellular matrix (ECM) using CRISPR-edited ARPE-19 cells. We introduced to these cells the p.R345W mutation in EFEMP1, which causes early-onset macular degeneration. The abnormal ECM binds active complement C3 and causes the formation of basal deposits by normal human fetal (hf)RPE cells. Human fetal RPE (hfRPE) cells grown on abnormal ECM or BrM explants from AMD donors show chronic activation of the alternative complement pathway by excessive deposition of C3b. This process is exacerbated by impaired ECM turnover via increased matrix metalloproteinase-2 activity. The local cleavage of C3 via convertase-independent mechanisms can be a new therapeutic target for early AMD.
Ferrara M, Eggenschwiler L, Stephenson A, Montieth A, Nakhoul N, Araùjo-Miranda R, Foster SC. The Challenge of Pediatric Uveitis: Tertiary Referral Center Experience in the United States. Ocul Immunol Inflamm 2018;:1-8.Abstract
PURPOSE: To describe the distribution, clinical findings, visual outcomes, treatment, and complications of children with uveitis at a tertiary referral ophthalmic center. METHODS: Retrospective cohort study. We reviewed the medical records of all patients ≤16 years with uveitis referred to Massachusetts Eye Research and Surgery Institution from March 2005 to July 2016. RESULTS: Of 286 included children, 62.24% were female. Mean age of onset was 8.4 years. The uveitis was mainly anterior (61.9%), recurrent (68.53%), bilateral (81.82%), and noninfectious (96.5%). Idiopathic cases accounted for 51.4%. The most frequent systemic association was juvenile idiopathic arthritis (34.96%). The majority of patients (78.32%) experienced complications. All patients, except one, needed systemic therapy. CONCLUSION: Pediatric uveitis is challenging to diagnose and manage, with frequent and potentially severe complications. Most cases were bilateral, recurrent, and idiopathic. Prompt referral to uveitis-specialized centers and an appropriate systemic therapy are mandatory for good visual outcomes.
Fu Z, Löfqvist CA, Liegl R, Wang Z, Sun Y, Gong Y, Liu C-H, Meng SS, Burnim SB, Arellano I, Chouinard MT, Duran R, Poblete A, Cho SS, Akula JD, Kinter M, Ley D, Hansen Pupp I, Talukdar S, Hellström A, Smith LEH. Photoreceptor glucose metabolism determines normal retinal vascular growth. EMBO Mol Med 2018;10(1):76-90.Abstract
The neural cells and factors determining normal vascular growth are not well defined even though vision-threatening neovessel growth, a major cause of blindness in retinopathy of prematurity (ROP) (and diabetic retinopathy), is driven by delayed normal vascular growth. We here examined whether hyperglycemia and low adiponectin (APN) levels delayed normal retinal vascularization, driven primarily by dysregulated photoreceptor metabolism. In premature infants, low APN levels correlated with hyperglycemia and delayed retinal vascular formation. Experimentally in a neonatal mouse model of postnatal hyperglycemia modeling early ROP, hyperglycemia caused photoreceptor dysfunction and delayed neurovascular maturation associated with changes in the APN pathway; recombinant mouse APN or APN receptor agonist AdipoRon treatment normalized vascular growth. APN deficiency decreased retinal mitochondrial metabolic enzyme levels particularly in photoreceptors, suppressed retinal vascular development, and decreased photoreceptor platelet-derived growth factor (Pdgfb). APN pathway activation reversed these effects. Blockade of mitochondrial respiration abolished AdipoRon-induced Pdgfb increase in photoreceptors. Photoreceptor knockdown of Pdgfb delayed retinal vascular formation. Stimulation of the APN pathway might prevent hyperglycemia-associated retinal abnormalities and suppress phase I ROP in premature infants.
Houston KE, Peli E, Goldstein RB, Bowers AR. Driving With Hemianopia VI: Peripheral Prisms and Perceptual-Motor Training Improve Detection in a Driving Simulator. Transl Vis Sci Technol 2018;7(1):5.Abstract
Purpose: Drivers with homonymous hemianopia (HH) were previously found to have impaired detection of blind-side hazards, yet in many jurisdictions they may obtain a license. We evaluated whether oblique 57Δ peripheral prisms (p-prisms) and perceptual-motor training improved blind-side detection rates. Methods: Patients with HH (n = 11) wore p-prisms for 2 weeks and then received perceptual-motor training (six visits) detecting and touching stimuli in the prism-expanded vision. In a driving simulator, patients drove and pressed the horn upon detection of pedestrians who ran toward the roadway (26 from each side): (1) without p-prisms at baseline; (2) with p-prisms after 2 weeks acclimation but before training; (3) with p-prisms after training; and (4) 3 months later. Results: P-prisms improved blind-side detection from 42% to 56%, which further improved after training to 72% (all P < 0.001). Blind-side timely responses (adequate time to have stopped) improved from 31% without to 44% with p-prisms (P < 0.001) and further improved with training to 55% (P = 0.02). At the 3-month follow-up, improvements from training were maintained for detection (65%; P = 0.02) but not timely responses (P = 0.725). There was wide between-subject variability in baseline detection performance and response to p-prisms. There were no negative effects of p-prisms on vehicle control or seeing-side performance. Conclusions: P-prisms improved detection with no negative effects, and training may provide additional benefit. Translational Relevance: In jurisdictions where people with HH are legally driving, these data aid in clinical decision making by providing evidence that p-prisms improve performance without negative effects.
Inomata T, Hua J, Nakao T, Shiang T, Chiang H, Amouzegar A, Dana R. Corneal Tissue From Dry Eye Donors Leads to Enhanced Graft Rejection. Cornea 2018;37(1):95-101.Abstract
PURPOSE: To assess the effect of dry eye disease (DED) in graft donors on dendritic cell (DC) maturation, host T-cell sensitization, and corneal allograft rejection. METHODS: Corneas of control (healthy donor) and DED mice (C57BL/6) were transplanted onto fully allogeneic naive BALB/c recipients (n = 10 mice/group). Long-term allograft survival was evaluated for 8 weeks. Corneas and draining lymph nodes (dLNs) were harvested at posttransplantation day 14 (n = 5 mice/group). The frequencies of MHCII CD11c DCs in the donor corneas and host dLNs and the frequencies of interferon (IFN)-γ and IL-17 CD4 T cells and Foxp3 expression by Tregs in host dLNs were investigated using flow cytometry. The enzyme-linked immunospot assay was used to assess host T-cell allosensitization through direct and indirect pathways (n = 3/group). RESULTS: Recipients of DED donor corneas showed significantly reduced graft survival (10%) compared with control mice (50% survival, P = 0.022), and had significantly increased frequencies of mature DCs in the grafted cornea (DED donor 44.0% ± 0.36% vs. healthy donor 35.4 ± 0.5%; P < 0.0001) and host dLNs (DED donor 25.1% ± 0.66% vs. healthy donor 13.7% ± 1.6%; P = 0.005). Frequencies of IFN-γ and IL-17 T cells were increased in the dLNs of recipients of DED corneas, whereas the expression (mean fluorescence intensity) of Foxp3 in Tregs was decreased significantly in these mice (DED donor 6004 ± 193 vs. healthy donor 6806 ± 81; P = 0.0002). Enzyme-linked immunospot analysis showed that the direct pathway of allosensitization was significantly amplified in recipients of grafts with DED (P = 0.0146). CONCLUSIONS: Our results indicate that DED in the donor is a significant risk factor for subsequent corneal allograft rejection.
Jakobiec FA, Zakka FR, Bojovic B. Ellipsoid Smooth Muscle Tumor of the Lower Eyelid: An Exploration of Its Possible Origin. Ophthal Plast Reconstr Surg 2018;34(1):e6-e10.Abstract
Ocular adnexal smooth muscle masses/neoplasms are extremely rare. Such lesions are comparatively more common in the conjunctiva than in the orbit and are most unusual in the eyelid. A 58-year-old woman slowly developed over 4 months a firm, movable sausage-shaped lesion in the deep lateral half of the right lower eyelid. The lesion ran parallel to and above the orbital rim. At surgery, the lesion was located between the orbicularis muscle and the inferior orbital septum. The term ellipsoid is used descriptively and does not imply any particular biologic behavior. Immunohistochemical evaluation revealed smooth muscle actin and desmin positivity. Due to the ubiquity of small blood vessels and the absence of smooth muscle bundles in the potential space between the orbicularis striated muscle and the inferior orbital septum, venular smooth muscle emerges as a highly likely source for the lesion.
Kaochar S, Dong J, Torres M, Rajapakshe K, Nikolos F, Davis CM, Ehli EA, Coarfa C, Mitsiades N, Poulaki V. ICG-001 Exerts Potent Anticancer Activity Against Uveal Melanoma Cells. Invest Ophthalmol Vis Sci 2018;59(1):132-143.Abstract
Purpose: Uveal melanoma (UM) is uniformly refractory to all available systemic chemotherapies, thus creating an urgent need for novel therapeutics. In this study, we investigated the sensitivity of UM cells to ICG-001, a small molecule reported to suppress the Wnt/β-catenin-mediated transcriptional program. Methods: We used a panel of UM cell lines to examine the effects of ICG-001 on cellular proliferation, migration, and gene expression. In vivo efficacy of ICG-001 was evaluated in a UM xenograft model. Results: ICG-001 exerted strong antiproliferative activity against UM cells, leading to cell cycle arrest, apoptosis, and inhibition of migration. Global gene expression profiling revealed strong suppression of genes associated with cell cycle proliferation, DNA replication, and G1/S transition. Gene set enrichment analysis revealed that ICG-001 suppressed Wnt, mTOR, and MAPK signaling. Strikingly, ICG-001 suppressed the expression of genes associated with UM aggressiveness, including CDH1, CITED1, EMP1, EMP3, SDCBP, and SPARC. Notably, the transcriptomic footprint of ICG-001, when applied to a UM patient dataset, was associated with better clinical outcome. Lastly, ICG-001 exerted anticancer activity against a UM tumor xenograft in mice. Conclusions: Using in vitro and in vivo experiments, we demonstrate that ICG-001 has strong anticancer activity against UM cells and suppresses transcriptional programs critical for the cancer cell. Our results suggest that ICG-001 holds promise and should be examined further as a novel therapeutic agent for UM.
Kaufman AR, Nosé RM, Pineda R. Descemetorhexis Without Endothelial Keratoplasty (DWEK): Proposal for Nomenclature Standardization. Cornea 2018;
Kheirkhah A, Satitpitakul V, Syed ZA, Müller R, Goyal S, Tu EY, Dana R. Factors Influencing the Diagnostic Accuracy of Laser-Scanning In Vivo Confocal Microscopy for Acanthamoeba Keratitis. Cornea 2018;Abstract
PURPOSE: To determine the factors that influence the sensitivity and specificity of laser-scanning in vivo confocal microscopy (IVCM) for diagnosing Acanthamoeba keratitis (AK). METHODS: This retrospective, controlled study included 28 eyes of 27 patients with AK and 34 eyes of 34 patients with bacterial keratitis (as the control group). All patients had undergone corneal imaging with a laser-scanning IVCM (Heidelberg Retina Tomograph 3 with the Rostock Cornea Module). The IVCM images were independently evaluated by 2 experienced and 2 inexperienced masked observers. Sensitivity and specificity of IVCM for diagnosing AK and the effects of various clinical and imaging parameters on the sensitivity were then investigated. RESULTS: Overall, IVCM had average sensitivity and specificity of 69.7% ± 2.5% and 97.1% ± 4.2% for experienced observers and 59.0% ± 7.6% and 92.7% ± 10.4% for inexperienced observers, respectively. However, the sensitivity did not show any significant association with the duration of disease, size of ulcer, depth of involvement, culture results, or cyst morphology. Although interobserver agreement was good (κ = 0.60, P < 0.001) for the experienced observers, it was only at a moderate level (κ = 0.48, P < 0.001) for the inexperienced observers. CONCLUSIONS: IVCM has a moderate sensitivity and a high specificity for diagnosis of AK. Although clinical parameters do not affect this diagnostic accuracy, a higher sensitivity is seen when images are interpreted by experienced observers.
King R, Struebing FL, Li Y, Wang J, Koch AA, Cooke Bailey JN, Gharahkhani P, Gharahkhani P, Gharahkhani P, Macgregor S, Allingham RR, Hauser MA, Wiggs JL, Geisert EE. Genomic locus modulating corneal thickness in the mouse identifies POU6F2 as a potential risk of developing glaucoma. PLoS Genet 2018;14(1):e1007145.Abstract
Central corneal thickness (CCT) is one of the most heritable ocular traits and it is also a phenotypic risk factor for primary open angle glaucoma (POAG). The present study uses the BXD Recombinant Inbred (RI) strains to identify novel quantitative trait loci (QTLs) modulating CCT in the mouse with the potential of identifying a molecular link between CCT and risk of developing POAG. The BXD RI strain set was used to define mammalian genomic loci modulating CCT, with a total of 818 corneas measured from 61 BXD RI strains (between 60-100 days of age). The mice were anesthetized and the eyes were positioned in front of the lens of the Phoenix Micron IV Image-Guided OCT system or the Bioptigen OCT system. CCT data for each strain was averaged and used to QTLs modulating this phenotype using the bioinformatics tools on GeneNetwork (www.genenetwork.org). The candidate genes and genomic loci identified in the mouse were then directly compared with the summary data from a human POAG genome wide association study (NEIGHBORHOOD) to determine if any genomic elements modulating mouse CCT are also risk factors for POAG.This analysis revealed one significant QTL on Chr 13 and a suggestive QTL on Chr 7. The significant locus on Chr 13 (13 to 19 Mb) was examined further to define candidate genes modulating this eye phenotype. For the Chr 13 QTL in the mouse, only one gene in the region (Pou6f2) contained nonsynonymous SNPs. Of these five nonsynonymous SNPs in Pou6f2, two resulted in changes in the amino acid proline which could result in altered secondary structure affecting protein function. The 7 Mb region under the mouse Chr 13 peak distributes over 2 chromosomes in the human: Chr 1 and Chr 7. These genomic loci were examined in the NEIGHBORHOOD database to determine if they are potential risk factors for human glaucoma identified using meta-data from human GWAS. The top 50 hits all resided within one gene (POU6F2), with the highest significance level of p = 10-6 for SNP rs76319873. POU6F2 is found in retinal ganglion cells and in corneal limbal stem cells. To test the effect of POU6F2 on CCT we examined the corneas of a Pou6f2-null mice and the corneas were thinner than those of wild-type littermates. In addition, these POU6F2 RGCs die early in the DBA/2J model of glaucoma than most RGCs. Using a mouse genetic reference panel, we identified a transcription factor, Pou6f2, that modulates CCT in the mouse. POU6F2 is also found in a subset of retinal ganglion cells and these RGCs are sensitive to injury.