The term biometrics is used to describe the process of analyzing biological and behavioral traits that are unique to an individual in order to confirm or determine his or her identity. Many biometric modalities are currently being researched and implemented including, fingerprints, hand and facial geometry, iris recognition, vein structure recognition, gait, voice recognition, etc... This project explores the possibility of using corneal topography measurements as a trait for biometric identification. Two new corneal topographers were developed for this study. The first was designed to function as an operator-free device that will allow a user to approach the device and have his or her corneal topography measured. Human subject topography data were collected with this device and compared to measurements made with the commercially available Keratron Piccolo topographer (Optikon, Rome, Italy). A third topographer that departs from the standard Placido disk technology allows for arbitrary pattern illumination through the use of LCD monitors. This topographer was built and tested to be used in future research studies. Topography data was collected from 59 subjects and modeled using Zernike polynomials, which provide for a simple method of compressing topography data and comparing one topographical measurement with a database for biometric identification. The data were analyzed to determine the biometric error rates associated with corneal topography measurements. Reasonably accurate results, between three to eight percent simultaneous false match and false non-match rates, were achieved.

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Purpose: To investigate the immune responses in cornea, ocular draining lymph nodes and spleen as well as the priming site of HSV-specific lymphocytes and their possible role in HSK development. To explore the possible treatment of HSK by transplanting corneal allograft and collagen artificial cornea. Methods: BALB/c mice corneas were infected with RE strain HSV-1. Immunohistochemistry of eye sections was performed and flow cytometry was carried out for cell suspension of cornea, TG, submandibular ocular draining lymph node (SMDLN),a non-ocular related lymph node and spleen at various times post HSV-1 eye inoculation. Results: There were strong immune responses in ocular draining lymph nodes post HSV-1 ocular infection, with a significant increasing number of innate cells as well as B cells and T cells. These changes were not observed in non-ocular related lymph nodes or spleen. An antigen specific response to HSV-1 antigen stimulation was observed <i>in vitro</i> for crude cells from ocular draining lymph node and to a lesser extent for spleen, but no changes were observed for the cells from non-ocular related lymph node. Interestingly, removal of ocular draining lymph nodes or spleen prior to HSV inoculation did not prevent HSK, but adversely impaired the control of viral replication, which was indicated by severe blepharitis and encephalitis. Both corneal allograft and collagen artificial cornea failed to survive in HSK eye, and retro-corneal membrane and degradation were the main obstacles for artificial cornea. Conclusions: HSV-specific lymphocytes are primed mainly in ocular draining lymph nodes, however, these cells might not be necessarily required for HSK development. Prevention of retro-corneal membrane seems to be important for survival of both corneal allograft and artificial cornea in HSK eyes.

Inherited retinal and corneal dystrophies represent a group of disorders with great genetic heterogeneity. Over 250 genes are associated with retinal diseases and 16 genes are causative of corneal dystrophies. This thesis is focused on finding the genetic causes of corneal dystrophy, Leber congenital amaurosis (LCA), Stargardt disease and retinitis pigmentosa in families from northern Sweden.  By whole exome sequencing a novel mutation, c.2816C&gt;T, p.Thr939Ile, in Collagen Type XVII, Alpha 1 chain, COL17A1, gene was identified in several families with epithelial recurrent erosion dystrophy (ERED). We showed that the COL17A1 protein is expressed in the basement membrane of the cornea, explaining the mutation involvement in the corneal symptoms. We could link all the families in this study to a couple born in the late 1700s confirming a founder mutation in northern Sweden. Our finding highlights role of COL17A1 in ERED and suggests screening of this gene in patients with similar phenotype worldwide. Furthermore the genetic causes in several retinal degenerations were identified. In one family with two recessive disorders, LCA and Stargardt disease, a novel stop mutation, c.2557C&gt;T, p.Gln853Stop, was detected in all LCA patients. In the Stargardt patients two intronic variants, the novel c.4773+3A&gt;G and c.5461-10T&gt;C, were detected in the ABCA4 gene. One individual was homozygous for the known variant c.5461-10T&gt;C and the other one was compound heterozygote with both variants present. Both variants, c.4773+3A&gt;G and c.5461-10T&gt;C caused exon skipping in HEK293T cells demonstrated by in vitro splice assay, proving their pathogenicity in Stargardt disease. Finally, in recessive retinitis pigmentosa, Bothnia Dystrophy (BD), we identified a second mutation in the RLBP1 gene, c.677T&gt;A, p.Met226Lys. Thus, BD is caused not only by common c.700C&gt;T variant but also by homozygosity of c.677T&gt;A or compound heterozygosity. Notably, known variant, c.40C&gt;T, p.R14W in the CAIV gene associated with a dominant retinal dystrophy RP17 was detected in one of the compound BD heterozygote and his unaffected mother. This variant appears to be a benign variant in the population of northern Sweden. In conclusion, novel genetic causes of retinal dystrophies in northern Sweden were found demonstrating the heterogeneity and complexity of retinal diseases. Identification of the genetic defect in COL17A1 in the corneal dystrophy contributes to understanding ERED pathogenesis and encourages refinement of IC3D classification. Our results provide valuable information for future molecular testing and genetic counselling of the families.

In vertebrates the cornea must maintain its transparency throughout adult life to ensure sight, and understanding the mechanisms underpinning corneal homeostasis are fundamental to developing new treatments to cure or prevent blindness. This study investigated the role the planar cell polarity pathway plays in the directed migration of adult corneal epithelial cells, in maintaining the homeostatic environment of the eye and during wound healing. RT-PCR confirmed, for the first time, the expression of multiple core PCP genes within human corneal epithelial (HCE) cells. Components of the PCP pathway were pharmacologically and genetically manipulated during wound healing of corneal epithelial cells and the importance of the downstream target JNK, and core PCP gene Vangl2, during wound healing was demonstrated. Manipulation of core PCP components was found also to directly affect the ability of HCE cells to realign and migrate in response to physical topographical cues in vitro. This study therefore indicated that PCP may regulate the directed migration of corneal epithelial cells as they travel over the basement membrane. Using conditional knockout mice the loss of Vangl2, a core PCP gene, and its effect on both planar and the apical-basal polarity of the corneal epithelium was investigated. Severe morphological defects were observed in Vangl2-null mice indicative of underlying problems in apical-basal polarity of the epithelial cells. The basement membrane of Vangl2-null cells was largely absent in vivo, which suggested that at least some of the planar defects were secondary to an unexpected failure of apical-basal polarity. This study has shown for the first time that PCP plays a crucial role in the maintenance of an adult vertebrate tissue, particularly during wound healing and maintenance of the corneal epithelium. It has also indicated a role for the core PCP gene, Vangl2, in setting up apical-basal polarity of these adult cells.

Master of Science / Department of Clinical Sciences / Amy Rankin / Objective- The purpose was to compare the efficacy and duration of 0.5% proparacaine, 0.5% bupivacaine, 2% lidocaine, and 2% mepivacaine on corneal sensitivity in clinically normal horses. Animals- 68 clinically normal horses Procedures- In group 1, 60 horses from the Kansas State University horse unit were assigned to receive one topical anesthetic in a completely randomized design. In group 2, 8 privately owned horses were sequentially treated with each of the topical anesthetics in random order with a one week washout period between drugs. Corneal sensitivity was assessed by corneal touch threshold (CTT) measurements which were taken with a Cochet-Bonnet aesthesiometer before anesthetic application (T0), 1 minute after (T1), every 5 minutes until 60 minutes (T5-T60), and then every 10 minutes until 90 minutes (T70-T90) after application. General linear mixed models were fitted to CTT in each design in order to assess the effects of topical anesthetics over time, accounting for repeated observations within individual horses. Results- Corneal sensitivity, as determined by CTT measurements, decreased immediately following application of the topical anesthetic, with persisting effects until T35 for proparacaine and mepivacaine, T45 for lidocaine, and T60 for bupivacaine. Maximal CTT reduction was achieved following application of bupivacaine or proparacaine, while mepivacaine was least effective. Conclusions and Clinical Relevance- All topical anesthetics reduced corneal sensitivity, though maximal anesthesia and effect of duration differed between drugs. For brief corneal anesthesia, 0.5% proparacaine or 2% lidocaine appeared adequate, while 0.5% bupivacaine may be most appropriate for procedures requiring longer periods of corneal anesthesia.

Neste trabalho foi desenvolvido um novo instrumento para monitoramento computadorizado da curvatura da região central anterior da córnea humana durante cirurgias refrativas. Através da projeção de um disco de Plácido na córnea, imagens dos reflexos são digitalizadas e processadas. Algoritmos baseados em técnicas de visão computacional e óptica geométrica determinam a curvatura da região central (-7 mm em diâmetro), com alta precisão e desempenho. Mapas coloridos com códigos de cor em dioptrias (proporcionais ao inverso do raio de curvatura) são gerados para auxiliar o oftalmologista durante a cirurgia. / In this work we have developed a new instrument for computerized monitoring of corneal central curvature during surgery. By projecting Placido Rings on the cornea, images of the reflections are digitized and processed. Algorithms based on computational vision and optical geometry determine the central curvature (-7 mm in diameter), with high performance and precision. Color coded maps in diopters (proportional to the inverse of the radius of curvature) are generated to aid the ophthalmologist during surgery.

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Made available in DSpace on 2014-06-11T19:22:13Z (GMT). No. of bitstreams: 0 Previous issue date: 2008-05-14Bitstream added on 2014-06-13T19:27:13Z : No. of bitstreams: 1 andreghetti_e_me_botfm.pdf: 433204 bytes, checksum: c3cfb144ceb98cb8b3ba7590f5346528 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Avaliar e comparar córneas de coelhos com implante de anel de FERRARA® com e sem revestimento de condroitin sulfato quanto à presença de hiperemia, secreção conjuntival, edema de córnea, vascularização corneana e extrusão do anel intraestromal e espessuras central e temporal da córnea. Pelo estudo histopatológico avaliar e comparar entre os dois grupos o número de camadas de células epiteliais sobre o anel, presença de alterações histopatológicas no estroma corneano, membrana de Descemet e endotélio. Foram estudados 30 coelhos albinos da raça Norfolk divididos em 2 grupos experimentais cada qual formado por 15 coelhos em cujas córneas do olho direito foram implantados o anel de FERRARA® clássico (G1) e anel de FERRARA® revestido por condroitin sulfato (G2). Os olhos esquerdos formaram o grupo controle. Em todos os grupos foram avaliados parâmetros clínicos: paquimetria central e temporal, hiperemia conjuntival, secreção, edema de córnea, vascularização e extrusão do anel. Foram também avaliados parâmetros morfológicos: número de camadas do epitélio, o estroma corneano, a membrana de Descemet e o endotélio. Os parâmetros clínicos foram avaliados em 3 M1 (1º dia pós-operatório), M2 (30º dia pós-operatório e M3 (60º dia pósoperatório). Os parâmetros morfológicos foram analisados no M3. As alterações encontradas foram descritas e comparadas através dos testes t de Student, Mann- Whitney, Wilcoxon para amostras independentes; Teste exato de Fisher, Teste Qui-quadrado, Teste de McNemar para amostras dependentes, conforme o parâmetro. Quanto à espessura central da córnea ocorreu um aumento estatísticamente significante entre os momentos antes e após a implantação nos dois grupos e aumento na espessura temporal apenas no G1. Os demais parâmetros clínicos não... / To evaluate and compare rabbit corneas with chondroitin-sulfatecoated and uncoated Ferrara ring implants as regards the presence of hyperemia, conjunctival secretion, corneal edema, corneal vascularization and extrusion of the intrastromal ring as well as central and temporal corneal thickness. To evaluate and compare the number of epithelial cell layers on the ring and the presence of histopathological alterations in the corneal stroma, Descemet’s membrane and endothelium between the two groups by means of a histopathological investigation. Thirty albinal Norfolk rabbits were studied in 2 experimental groups. Each group comprised 15 rabbits whose right-eye cornea received a classic Ferrara ring implant in group 1 (G1) and a Ferrara ring coated by chondroitin sulfate in Group 2 (G2). Their left eyes formed the control group. The following clinical parameters were evaluated in all groups: central and temporal pachymetry, conjunctival hyperemia, secretion, corneal edema, vascularization and ring extrusion. Morphological parameters were also evaluated as follows: number of epithelial layers, corneal stroma, Descemet’s membrane and endothelium. The clinical parameters were evaluated at 3 moments: M1 (first post-operative day), M2 (30th post-operative day) and M3 (60th post-operative day). The morphological parameters were analyzed at M3. The alterations found were described and compared by Student’s t, Mann- Whitney’s and Wilcoxon’s tests for independent samples and by Fisher’s exact, Chi-Square and McNemar’s tests for dependent samples, according to the different parameters. As regards central corneal thickness, a statistically significant increase was found between the moments prior to and after implantation in the two groups. Temporal thickness increase was observed only in G1.The other clinical parameters showed no significant ...(Complete abstract, click electronic access below)

Corneal degenerative diseases and opacity are leading causes of corneal impairment and blindness worldwide. Like many epithelial tissues, the constant renewal of transparent corneal epithelial cells is essential for a lifelong healthy cornea and optimal vision. The limbus (the boundary between the cornea and the conjunctiva) is believed to be the site that harbours adult stem cells responsible for corneal maintenance and repair after injury, referred to as limbal epithelial stem cells (LESCs). In the basal limbal epithelium, an active LESC subset divides to yield progenitor cells that migrate centripetally into the corneal epithelium for cell renewal. This asymmetric division however, is assumed to be regulated by a balance between cell renewal and loss of cells from the corneal surface. The search for specific LESC molecular markers has been difficult and to date there are few if any candidate markers that unambiguously identify LESCs but not their immediate progeny. Consequently, LESC clonality, activity and proliferative dynamics have remained poorly understood. In addition, the nature of the regulatory molecular pathways involved during LESC activity is still an open key question. In this research project, we identified stem cells on the ocular surface of the eye, assayed their activity and demonstrated quantitively for the first time how the cornea responds to damage. The retention of DNA labelling reagents in control and wounded corneas was combined with clonal analyses of cell division and migration using mice mosaic for reporter LacZ expression. Corneal transplant in LacZ reporter transgenic mice showed migration of LacZ-positive cells into the donor corneal button, with long-term disruption of patterns of migration. Corneal epithelial scrape wounds at the periphery also showed long– term disruption. Label retention suggested a small but statistically significant proliferation response of LESCs to injury, but this was attenuated or absent in aging mice and Pax6 mutants. The Hippo signalling pathway has been shown to have promising results in regulating stem cell activity and proliferation in many organs, however, its effect on LESC proliferation is unknown. Here, we investigated the regulatory role of the Hippo−YAP signalling pathway during cell proliferation, and determined whether the label retention assay in a uniform population of dividing cells is a real indicator of slow-cycling cells in vivo. Cell-cycling kinetics, Abstract v proliferation rate, and label retention were determined in a spontaneous human corneal epithelial (HCE-S) cell line, using double-labelling IdU and EdU thymidine analogues. During homeostasis, HCE-S cells underwent approximately one cell cycle per day, however, cells in which YAP-dependent signalling was activated by 17-Allylamino-17-demethoxygeldanamycin (17-AAG), an inhibitor of heat shock protein 90 (Hsp90), showed slower proliferation rate and longer cell-cycle time. In vitro label-retention assay in confluent cultures estimated number of ~3-4 cell cycles needed to dilute out the label from slow-cycling cells in vivo. The data are suggestive that the Hippo pathway has a potential regulatory role in proliferative corneal epithelium, and that label-retention assay is a real indicator of slow-cycling cells. Furthermore, this research observed the proliferative dynamics of conjunctival stem cells. Clonal analysis of patterns of cell growth in the conjunctiva were analysed following tamoxifen-induction of LacZ transgene activity. The long−term presence of coherent patches of LacZ-positive cells suggested the presence of long-lived conjunctival stem cells but that the turnover time for the bulbar conjunctival epithelium may be more than 16 weeks. The key results of this research are that the limbus is the niche for stem cells, that there is a unidirectional migration of cells from the limbus to the corneal epithelium during homeostasis, but this is disrupted, perhaps permanently, by wounding. We find only a mild response of limbal epithelial stem cells to acute corneal injury, which is reduced to no response with age and is dependent on genetic background.