Academic literature on the topic 'Cornea – Diseases'
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Journal articles on the topic "Cornea – Diseases"
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Chendran, Prema, Yong Meng Hsien, and Wan Haslina Wan Abdul Halim. "Multifacet of Cornea Patch Graft in Anterior Segment Diseases." Case Reports in Ophthalmological Medicine 2019 (November 11, 2019): 1–5. http://dx.doi.org/10.1155/2019/6862487.
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Incidence of cornea melting or perforation is commonly seen in variety of cornea conditions. It can cause debilitating vision loss and impair patient’s daily activity. Several techniques have been described to surgically treat cornea perforation and melting. In this article, a series of corneal diseases treated with corneal patch graft are highlighted to relate different approach of cornea patch graft surgery. Post-operative management and complications are discussed.
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Guérin, Louis-Philippe, Gaëtan Le-Bel, Pascale Desjardins, Camille Couture, Elodie Gillard, Élodie Boisselier, Richard Bazin, Lucie Germain, and Sylvain L. Guérin. "The Human Tissue-Engineered Cornea (hTEC): Recent Progress." International Journal of Molecular Sciences 22, no. 3 (January 28, 2021): 1291. http://dx.doi.org/10.3390/ijms22031291.
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Each day, about 2000 U.S. workers have a job-related eye injury requiring medical treatment. Corneal diseases are the fifth cause of blindness worldwide. Most of these diseases can be cured using one form or another of corneal transplantation, which is the most successful transplantation in humans. In 2012, it was estimated that 12.7 million people were waiting for a corneal transplantation worldwide. Unfortunately, only 1 in 70 patients received a corneal graft that same year. In order to provide alternatives to the shortage of graftable corneas, considerable progress has been achieved in the development of living corneal substitutes produced by tissue engineering and designed to mimic their in vivo counterpart in terms of cell phenotype and tissue architecture. Most of these substitutes use synthetic biomaterials combined with immortalized cells, which makes them dissimilar from the native cornea. However, studies have emerged that describe the production of tridimensional (3D) tissue-engineered corneas using untransformed human corneal epithelial cells grown on a totally natural stroma synthesized by living corneal fibroblasts, that also show appropriate histology and expression of both extracellular matrix (ECM) components and integrins. This review highlights contributions from laboratories working on the production of human tissue-engineered corneas (hTECs) as future substitutes for grafting purposes. It overviews alternative models to the grafting of cadaveric corneas where cell organization is provided by the substrate, and then focuses on their 3D counterparts that are closer to the native human corneal architecture because of their tissue development and cell arrangement properties. These completely biological hTECs are therefore very promising as models that may help understand many aspects of the molecular and cellular mechanistic response of the cornea toward different types of diseases or wounds, as well as assist in the development of novel drugs that might be promising for therapeutic purposes.
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Han, Xiao, Yubao Zhang, Yirui Zhu, Yanzhi Zhao, Hongwei Yang, Guo Liu, Sizhu Ai, et al. "Quantification of biomechanical properties of human corneal scar using acoustic radiation force optical coherence elastography." Experimental Biology and Medicine 247, no. 6 (December 3, 2021): 462–69. http://dx.doi.org/10.1177/15353702211061881.
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Biomechanical properties of corneal scar are strongly correlated with many corneal diseases and some types of corneal surgery, however, there is no elasticity information available about corneal scar to date. Here, we proposed an acoustic radiation force optical coherence elastography system to evaluate corneal scar elasticity. Elasticity quantification was first conducted on ex vivo rabbit corneas, and the results validate the efficacy of our system. Then, experiments were performed on an ex vivo human scarred cornea, where the structural features, the elastic wave propagations, and the corresponding Young’s modulus of both the scarred region and the normal region were achieved and based on this, 2D spatial distribution of Young’s modulus of the scarred cornea was depicted. Up to our knowledge, we realized the first elasticity quantification of corneal scar, which may provide a potent tool to promote clinical research on the disorders and surgery of the cornea.
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Singh, Manmohan, Achuth Nair, Salavat R. Aglyamov, and Kirill V. Larin. "Compressional Optical Coherence Elastography of the Cornea." Photonics 8, no. 4 (April 7, 2021): 111. http://dx.doi.org/10.3390/photonics8040111.
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Assessing the biomechanical properties of the cornea is crucial for detecting the onset and progression of eye diseases. In this work, we demonstrate the application of compression-based optical coherence elastography (OCE) to measure the biomechanical properties of the cornea under various conditions, including validation in an in situ rabbit model and a demonstration of feasibility for in vivo measurements. Our results show a stark increase in the stiffness of the corneas as IOP was increased. Moreover, UV-A/riboflavin corneal collagen crosslinking (CXL) also dramatically increased the stiffness of the corneas. The results were consistent across 4 different scenarios (whole CXL in situ, partial CXL in situ, whole CXL in vivo, and partial CXL in vivo), emphasizing the reliability of compression OCE to measure corneal biomechanical properties and its potential for clinical applications.
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Yang, Seung Ahn, Su Hwan Park, and Ji Eun Lee. "Clinical Use of Mini-Scleral Contact Lens in Ocular Surface Diseases." Annals of Optometry and Contact Lens 21, no. 3 (September 30, 2022): 99–103. http://dx.doi.org/10.52725/aocl.2022.21.3.99.
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A scleral contact lens lies on the sclera, not the cornea, which differs from a rigid gas permeable (RGP) contact lens, and has shown successful clinical outcomes in patients unable to tolerate glasses or RGP contact lenses because of a severely deformed cornea. In addition, a scleral lens forms a tear film between the cornea and contact lens that stabilizes the ocular surface and could be a useful therapeutic option. The mini-scleral contact lens is a useful therapeutic option for visual improvement and symptom control in patients with corneal abnormalities such as keratoconus, corneal opacity, ocular surface disease, and irregular corneal astigmatism.
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Hussain, Noor Ahmed, Francisco C. Figueiredo, and Che J. Connon. "Use of biomaterials in corneal endothelial repair." Therapeutic Advances in Ophthalmology 13 (January 2021): 251584142110582. http://dx.doi.org/10.1177/25158414211058249.
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Human corneal endothelium (HCE) is a single layer of hexagonal cells that lines the posterior surface of the cornea. It forms the barrier that separates the aqueous humor from the rest of the corneal layers (stroma and epithelium layer). This layer plays a fundamental role in maintaining the hydration and transparency of the cornea, which in turn ensures a clear vision. In vivo, human corneal endothelial cells (HCECs) are generally believed to be nonproliferating. In many cases, due to their nonproliferative nature, any damage to these cells can lead to further issues with Descemet’s membrane (DM), stroma and epithelium which may ultimately lead to hazy vision and blindness. Endothelial keratoplasties such as Descemet’s stripping automated endothelial keratoplasty (DSAEK) and Descemet’s membrane endothelial keratoplasty (DEK) are the standard surgeries routinely used to restore vision following endothelial failure. Basically, these two similar surgical techniques involve the replacement of the diseased endothelial layer in the center of the cornea by a healthy layer taken from a donor cornea. Globally, eye banks are facing an increased demand to provide corneas that have suitable features for transplantation. Consequently, it can be stated that there is a significant shortage of corneal grafting tissue; for every 70 corneas required, only 1 is available. Nowadays, eye banks face long waiting lists due to shortage of donors, seriously aggravated when compared with previous years, due to the global COVID-19 pandemic. Thus, there is an urgent need to find alternative and more sustainable sources for treating endothelial diseases, such as utilizing bioengineering to use of biomaterials as a remedy. The current review focuses on the use of biomaterials to repair the corneal endothelium. A range of biomaterials have been considered based on their promising results and outstanding features, including previous studies and their key findings in the context of each biomaterial.
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Schultz, C. L., A. G. Buret, M. E. Olson, H. Ceri, R. R. Read, and D. W. Morck. "Lipopolysaccharide Entry in the Damaged Cornea and Specific Uptake by Polymorphonuclear Neutrophils." Infection and Immunity 68, no. 3 (March 1, 2000): 1731–34. http://dx.doi.org/10.1128/iai.68.3.1731-1734.2000.
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ABSTRACT Bacterial lipopolysaccharide (LPS) is an important agent of induction of ocular pathology following corneal injury or wearing of contaminated contact lenses. The mechanism of LPS uptake through the corneal epithelium is unclear, and the role played by inflammatory cells in this phenomenon has not been previously assessed. Fluorescein isothiocyanate-labeled LPS from Escherichia coli was deposited onto the abraded corneas of New Zealand White rabbits. Epifluorescence microscopy of living excised corneas revealed diffuse LPS staining in the epithelial and stromal layers only in the vicinity of the abrasion. In addition, specific cellular uptake of LPS was suggested by fluorescence staining of cells along the abrasion site. In a second series of experiments, an anti-CD18 polyclonal antibody was used to block infiltration of polymorphonuclear neutrophils (PMN) into the cornea. In these experiments, a diffuse distribution of fluorescent LPS was still observed along the abrasion, but the specific cellular uptake was abolished. The findings indicate that LPS enters the cornea via diffuse penetration at sites of injury and that specific cellular uptake of LPS occurs within the cornea via PMN which have migrated into the damaged tissue.
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Cole, Nerida, Mark Krockenberger, Fiona Stapleton, Shamila Khan, Emma Hume, Alan J. Husband, and Mark Willcox. "Experimental Pseudomonas aeruginosa Keratitis in Interleukin-10 Gene Knockout Mice." Infection and Immunity 71, no. 3 (March 2003): 1328–36. http://dx.doi.org/10.1128/iai.71.3.1328-1336.2003.
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ABSTRACT Pseudomonas aeruginosa keratitis is one of the most destructive diseases of the cornea. The host response to this infection is critical to the outcome. The cytokine interleukin-10 (IL-10) is thought to play an important role in modulating excessive inflammation and antimicrobial defenses. We have found that in IL-10−/− mice there is a significant decrease in bacterial load in corneas at 7 days postchallenge with P. aeruginosa. This decrease was accompanied by a reduction in neutrophil numbers in the cornea and changes in cytokine levels compared to those of wild-type mice. A characteristic increase in neovascularization in the cornea was found in the IL-10−/− mice. This increased angiogenesis correlated with an increased expression of KC, whereas the kinetics of macrophage inflammatory peptide 2 expression correlated with neutrophil numbers. This finding suggests that KC may play a role in corneal angiogenesis. The source of IL-10 in mouse corneas was identified as a subpopulation of infiltrating cells and keratocytes. This study demonstrates that IL-10 plays an important role in regulating the balance of inflammatory mediators during P. aeruginosa infection of the cornea.
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Maharramov, P. M. "Prevalence rate of cornea diseases according materials of outpatient facilities in Baku city." Russian Ophthalmological Journal 14, no. 2 (June 20, 2021): 23–26. http://dx.doi.org/10.21516/2072-0076-2021-14-2-23-26.
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Purpose: to assess the prevalence of corneal diseases using the data on the incidence of visits to outpatient facilities in the city of Baku. Material and methods. The data, presented by outpatient facilities for the year 2017, were statistically analyzed. Results. It was revealed that, for every 100 000 people, there were 266.1±3.4 cases of corneal diseases of which 97.9 ± 2.1 were infectious and 166.9 ± 2.7 were noninfectious diseases. Corneal neoplasms were detected in 1.3 ± 0.2 cases. The ratio of non-infectious and infectious diseases ofthe cornea was ca. 1.7. The lowest prevalence rate of both infectious and non-infectious diseases of the cornea was detected in children aged 0 to 9 years. In older age groups, the change of prevalence of corneal diseases was found to be chaotic. The trends of age-related prevalenceof infectious vs. non-infectious diseases of the cornea were basically similar; the highest rate was detected among patients aged 60–69. Conclusion.According to the appealability data, the prevalence rate of corneal diseases is rather high and age-dependent with a prevailing share of non-infectious corneal pathologies. In male population, this rate is notably lower than in female population.
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Semak, G. R., V. A. Zakharava, I. Yu Zherka, and P. Yu Yudin. "Lumican expression in chronic degenerative cornea diseases." Doklady of the National Academy of Sciences of Belarus 65, no. 3 (July 16, 2021): 345–54. http://dx.doi.org/10.29235/1561-8323-2021-65-3-345-354.
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The pattern of lumican expression in corneal explants of patients with chronic dystrophic cornea diseases and the changes in its expression after 1 % sodium hyaluronate expression are established. The prospective study included 37 patients with chronic dystrophic diseases of the cornea: keratopathies in the outcome of keratitis (20 cases) and endothelial-epithelial dystrophy (17 cases). The patients were divided into 2 groups. The first group in the preoperative period received the injections of 1 % low molecular weight sodium hyaluronate, the second group did not receive additional treatment. All patients included in the study underwent penetrating keratoplasty. The immunohistochemical study of corneal explants was performed using primary monoclonal antibodies to lumican with subsequent morphometric evaluation of the preparations. The proportion of pixels with high and moderate intensity and the index of expression intensity in immunopositive regions were calculated. In the group of patients with aggressive keratitis, the intensity of lumican expression both in the epithelium and in the corneal stroma was statistically significantly higher than in the control group and decreased with the use of 1 % low molecular weight sodium hyaluronate. After the leukoma formation, the expression of lumican both in the epithelium and in the corneal stroma was comparable to that in the control group with higher parameters of epithelial expression after sodium hyaluronate administration. In the groups of endothelial-epithelial dystrophy, an increase in the intensity of expression was noted after sodium hyaluronate injections. The noted increase in the epithelial expression of lumican against the background of pronounced alteration is accompanied by its gradual decrease as the regeneration is completed. An important factor is its normal content in the corneal stroma, since both a sharp increase and low expression parameters are accompanied by a decrease in corneal transparency.
Dissertations / Theses on the topic "Cornea – Diseases"
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Schultes, Klaus. "Ultrastructural characterization of ultraviolet induced corneal disease : an animal model." Master's thesis, University of Cape Town, 1994. http://hdl.handle.net/11427/27046.
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The majority of ancient people worshipped the sun and viewed it as a health - bringing deity. During the eighteenth and nineteenth century therapeutic benefits of sunlight exposure were beginning to be understood and by the end of the nineteenth century the importance of ultraviolet radiation was being realized. Danish physician Niels Finsen, whom many regard as the father of ultraviolet phototherapy, also stressed that it was ultraviolet radiation in the solar spectrum which cause sunburn. We now recognize that the small portion of ultraviolet radiation which reaches the earth's surface is not necessarily therapeutic, but in fact could be harmful to humans. There are numerous accounts of the harmful effects of UV radiation to the skin and the eye as a whole. These effects may be caused by either acute or chronic exposure to UV radiation. For example, some acute effects of UV-B radiation include conjunctivitis and photokeratitis. "Snow blindness" and "arc welders eye" are further examples of acute ultraviolet damage specifically to the surface of the cornea. On the other hand, chronic exposure to ultraviolet radiation is thought to be responsible for pterygia, climatic droplet keratopathy Hill and Maske (1989), cancers of the external eye, cataracts and various types of retinal diseases. The present study is an extension of ongoing studies on ultraviolet radiation damage to the cornea in the Department of Ophthalmology, University of Cape Town and Groote Schuur Hospital. Their specific interest lies in the causes and treatment of climatic droplet keratopathy. The aims of the present study are: 1) Establish a possible role of ultraviolet B radiation in human corneal diseases such as climatic droplet keratopathy and pterygium using the rabbit as an animal model. 2) Determine by means of SEM the initial effects and subsequent recovery of the epithelium after a 3-hour dose of ultraviolet B radiation. We refer to this study as "acute" response to ultraviolet B radiation. 3) To try and confirm the effects observed by SEM with ultrastructural studies using TEM. 4) In addition, we are also looking at the possible effects after exposing rabbit cornea to a daily dose of low level ultraviolet B radiation, over a long period of time. We refer to this as chronic exposure to ultraviolet B radiation. It is hoped that by exposing rabbits to ultraviolet light, principally ultraviolet B radiation, diseases similar to those found in humans could be simulated and disease progression studied. People are generally exposed to substantial amounts of UV radiation for a very long time. Since people generally live longer they will be exposed to an ever-increasing amount of solar UV radiation and subsequently, there is an increasing risk of developing corneal diseases. The possible threat to the ozone is also a real possibility and could lead to increased levels of ultraviolet radiation reaching the earth's surface. This will require a greater understanding of the very nature of corneal damage due to acute and chronic exposure. This study focusses mainly on the acute response to UV-B radiation since most studies have investigated effects of prolonged exposure to UV light. Accordingly, much less is known about acute exposure. Many people suffering from acute UV B radiation effects probably never visit the ophthalmologist or wait for a couple of days. This could also contribute to the fact that effects of short-term damage is not well documented.
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Yang, Juan. "Universal corneal epithelial-like cells derived from human embryonic stem cells in a defined, xeno-free, and albumin-free condition for cellularization of a corneal scaffold." Thesis, University of Macau, 2018. http://umaclib3.umac.mo/record=b3953938.
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Hammar, Björn. "Two New Corneal Diseases Characterized by Recurrent Erosions." Doctoral thesis, Linköpings universitet, Oftalmologi, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-17490.
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Recurrent corneal erosions are a common complication of superficial corneal wounds. They most commonly arise following a trauma, in association with various corneal dystrophies, or are idiopathic. The main aim of this thesis was to investigate two hereditary corneal diseases with recurrent erosions in order to find out if they had been described before, and more specifically to describe the clinical picture and the morphological changes, differentiate them from other known autosomal dominant corneal dystrophies with a clinical resemblance, and to exclude genetic linkage to known corneal dystrophies with autosomal-dominant inheritance and a clinical resemblance. The thesis is based on two families of subjects belonging to different phenotypes. The subjects from Småland (Dystrophia Smolandiensis) belonged to a six-generation family, which included 171 individuals of whom 44 were affected individuals, and the family from Hälsingland (Dystrophia Helsinglandica) included sevengenerations of 342 individuals, of whom 84 were affected. The individuals in both families were investigated by collection of medical history through medical records and questionnaires assessing different aspects of the diseases, pedigree analysis, and from clinical examination. Haplotype analysis was used to exclude genetic linkage of both diseases to known autosomal-dominant corneal dystrophies with a clinical resemblance. The morphological changes in Dystrophia Smolandiensis were investigated by examining affected individuals with in-vivo confocal microscopy and/or slit-lamp biomicroscopy, and examining corneal tissue samples using histopathology and immunohistochemistry. In Dystrophia Helsinglandica, the morphological changes were described using in-vivo confocal microscopy and/or slit-lamp biomicroscopy, but also using videokeratography and corneal sensitivity measurement. The main results were the findings of two new corneal disorders with autosomal dominant inheritance, characterized by recurrent corneal erosions. In Dystrophia Smolandiensis the symptoms often started within the first year of life. The number of recurrences per year was highest from the onset and for about 30-40 years, and the duration of recurrence could stretch up to 21 days. The frequency of recurrences was variable in the disease from continuous symptoms to once a year and tended to decrease later in life. The risk of having recurrences did not disappear completely with age. Typical precipitating factors of recurrence were draught and a common cold. About two thirds of the affected individuals responded well to oral vitamin B treatment, but no other therapy has so far been successful. In Dystrophia Smolandiensis development of corneal opacifications or secondary scarring of varying type and degree was seen in about half of the subjects. Opacifications were first noted at the age of about 7 years, but usually first seen at the age of 20-40 years. Corneal grafting was performed in nine individuals, and recurrences were seen in all grafts. The corneal buttons showed epithelial hyperplasia, partial or total loss of Bowman’s layer, and subepithelial fibrosis in the light microscope. The deeper stroma, Descement’s membrane, and endothelium were normal. Confocal microscopy confirmed loss of Bowman’s layer and revealed that the corneal nerves either were normal in their sub-basal plexa or showed signs of regeneration. None of the morphological findings were specific. We believe that the opacifications are reactive corneal changes to repeated erosive events. The onset in Dystrophia Helsinglandica was usually at the age of 4-7 years and late-developing subepithelial fibrosis not significantly affecting visual acuity was seen in all affected individuals over the age of 37 years. The number of recurrences per year was highest from the onset and for about 20-30 years, and the duration of recurrence was usually up to about a week. The frequency of recurrences tended to decrease in the disease with increasing age, but did not cease completely. The precipitating factor of recurrence was typically a minor trauma. No therapy has so far been successful in the family. The corneal changes of affected individuals were classified into different stages from a nearly normal cornea to progressive fairly discrete subepithelial fibrosis of the central cornea. Discrete localized Subepithelial fibrosis in the periphery or mid-periphery (stage I) was the sole finding in 12% of the individuals. A more widespread subepithelial fibrosis, mainly in the mid-periphery, was found in 31% of the individuals (stage II). In stage III, the subepithelial fibrosis engaged the central cornea but did not affect the vision to a significant degree. In late phases of stage III small jellylike corneal irregularities could be seen. We believe that the opacifications are reactive changes to repeated erosive events. In conclusion this thesis describes two new corneal disorders – Dystrophia Smolandiensis and Dystrophia Helsinglandica.
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Alzubaidi, Rania S. M. "Fully automated computer system for diagnosis of corneal diseases. Development of image processing technologies for the diagnosis of Acanthamoeba and Fusarium diseases in confocal microscopy images." Thesis, University of Bradford, 2017. http://hdl.handle.net/10454/17142.
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Confocal microscopy demonstrated its value in the diagnosis of Acanthamoeba and fungal keratitis which considered sight-threatening corneal diseases. However, it can be difficult to find and train confocal microscopy graders to accurately detect Acanthamoeba cysts and fungal filaments in the images. Use of an automated system could overcome this problem and help to start the correct treatment more quickly. Also, response to treatment can be difficult to assess in infectious keratitis using clinical examination alone, but there is evidence that the morphology of filaments and cysts may change over time with the use of correct treatment. An automated system to analyse confocal microscopy images for such changes would also assist clinicians in determining whether the ulcer is improving, or whether a change of treatment is needed.
This research proposes a fully automated novel system with GUI to detect cysts and hyphae (filaments) and measure useful quantitative parameters for them through many stages; Image enhancement, image segmentation, quantitative analysis for detected cysts and hyphae, and registration and tracking of ordered sequence of images.
The performance of the proposed segmentation procedure is evaluated by comparing between the manual and the automated traced images of the dataset that was provided by the Manchester Royal Eye Hospital. The positive predictive values rate of cysts for Acanthamoeba images was 76%. For detected hyphae in Fusarium images, many standard measurements were computed. The accuracy of their values was quantified by calculating the percent error rate for each measurement and which ranged from 23% to 49%.
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Frida, Jonsson. "Underlying genetic mechanisms of hereditary dystrophies in retina and cornea." Doctoral thesis, Umeå universitet, Institutionen för medicinsk biovetenskap, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-130538.
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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>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>T, p.Gln853Stop, was detected in all LCA patients. In the Stargardt patients two intronic variants, the novel c.4773+3A>G and c.5461-10T>C, were detected in the ABCA4 gene. One individual was homozygous for the known variant c.5461-10T>C and the other one was compound heterozygote with both variants present. Both variants, c.4773+3A>G and c.5461-10T>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>A, p.Met226Lys. Thus, BD is caused not only by common c.700C>T variant but also by homozygosity of c.677T>A or compound heterozygosity. Notably, known variant, c.40C>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.
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Zderic, Vesna. "Ultrasound-enhanced ocular drug delivery /." Thesis, Connect to this title online; UW restricted, 2004. http://hdl.handle.net/1773/8085.
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Hamilton, Kirsten School of Optometry & vVsion Science UNSW. "Corneal hydration and the accuracy of Goldmann tonometry." Awarded by:University of New South Wales. School of Optometry and vVsion Science, 2006. http://handle.unsw.edu.au/1959.4/30468.
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The purpose of this thesis was to investigate the effect of corneal swelling on the accuracy of Goldmann tonometry estimates of intraocular pressure (IOP). In the first experiment, central corneal thickness (CCT, ultrasonic pachymetry), IOP (Goldmann tonometry) and corneal curvature (keratometry) was measured in one eye of 25 subjects every two hours for 24 hours, except for 8 hours overnight (no measurements taken), and for the first two hours after awakening (measurement frequency 20 minutes). CCT (+20.1??10.9 pm) and IOP (+3.1??2.4 mmHg) peaked on eye opening, and then decreased at a similar rate (r=0.967, p<0.001) for the next two hours. Corneal swelling may have influenced the accuracy of Goldmann IOP measurements during this time. In the second and third studies, the CCT, IOP and corneal curvature were measured in both eyes of two groups of 25 subjects before and after the induction of corneal swelling, resulting from two hours of monocular closed eye contact lens wear. The increase in IOP was correlated to the increase in CCT at a rate of 0.33 to 0.48 mmHg per 10 pm, which signified an overestimation error in Goldmann IOP measurement. However, the change in IOP could not be accounted for solely by the change in CCT. In the fourth study, CCT, IOP and corneal curvature were used in conjunction with the Orssengo-Pye algorithm to determine the range of Young's modulus in the normal population, which was 0.29??0.06 MPa. Physiological variations in Young's modulus had a similar effect on Goldmann tonometry to CCT. In the fifth study, the data collected for studies 2 and 3 was used to calculate the Young's modulus changes associated with corneal swelling, again with the assistance of the Orssengo-Pye algorithm. No systematic change in Young's modulus was recorded after contact lens wear, but the model suggested that corneal biomechanical changes were responsible for the remainder of the change in IOP. All experimental results were combined to develop a model to calculate the diurnal variation of Goldmann IOP errors. The likely error in IOP due to overnight corneal swelling was 0.6 to 1.4 mmHg, which may explain as much as 45% (1.4 mmHg) of the 3.1 mmHg diurnal variation of IOP. In summary, small amounts of corneal swelling were shown to have a clinically significant impact on the accuracy of Goldmann tonometry. This may interfere with the measurement of the diurnal variation of IOP, particularly if measurements are taken prior to the resolution of overnight corneal swelling.
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Barbosa, Virginia Tessarine. "Emprego do etil-cianoacrilato ou do octil-cianoacrilato no preenchimento de lesões corneais, após ceratectomia lamelar em coelhos /." Jaboticabal : [s.n.], 2007. http://hdl.handle.net/11449/89026.
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Orientador: José Luiz LausBanca: Duvaldo Eurides
Banca: Márcia Rita Fernandes Machado
Resumo: São diversas as indicações para o emprego de adesivos derivados do cianoacrilato na área médica. Em oftalmologia humana, há décadas, estes biomateriais são utilizados com resultados satisfatórios. Entretanto, em veterinária, ainda são escassos o conhecimento de suas propriedades e a sua aplicação. Considerando o interesse em se avaliar o comportamento do etil-cianoacrilato, comparativamente ao octil-cianoacrilato, clínica e histopatologicamente, em córneas de coelhos, empregaramse 36 animais, nos quais, após ceratectomia lemelar de 3 mm de diâmetro, os adesivos foram aplicados e recobertos por uma fina película acelular. No pós-operatório, foram realizadas avaliações gerais (dias 1 a 10), exames oftálmicos (dias 0, 1, 3, 5, 7, 10, 14, 21, 30, 44 e 60) e estudos histopatológicos (períodos 3, 7, 14, 21, 30 e 60). Consideraram-se, ainda, os custos e disponibilidade dos adesivos. Clinicamente, houve diferença significativa para as variáveis, consumo de água, atitude, blefarite, edema corneal, teste da fluoresceína e tempo de permanência dos adesivos. À histopatologia, para o etil-cianoacrilato, já nos primeiros períodos de avaliação, observou-se epitelização corneal, organização do colágeno e moderada reação inflamatória. Para o octil-cianoacrilato, constatou-se a permanência do adesivo até as fases mais tardias, sob o qual, mais lentamente os eventos de reepitelização e organização do colágeno ocorreram com reação inflamatória discreta. Os custos e disponibilidade de aquisição do etil-cianoacrilato foram mais acessíveis do que os do octil-cianoacrilato.
Abstract: There are several indications for the employment of adhesives derived from the cyanoacrylate in the medical area. In human ophthalmology, from decades, the cyanoacrylates have been used with satisfactory results. However, in veterinary medicine, there is a scarcity of knowledge of its properties and applications. Considering the objective of evaluating the behavior of the ethyl-cyanoacrylate, comparatively to octhyl-cyanoacrylate, clinically and histopatologically, in rabbit corneas, there were used 36 animals. After lamellar keratectomy with 3 mm of diameter the adhesives was applied and recovered with a fine pellicle. In the post operative period general (days 1 to 10), ophthalmic (days 0, 1, 3, 5, 7, 14, 21, 30, 44 and 60) and hystopathologic (periods 3, 7, 14, 21, 30 and 60) exams was performed. There was also considered the costs and accessibility of the adhesives. Clinically, there were significant differences for the variables water consumption, attitude, blepharitis, corneal edema, fluorescein test and adhesive permanence time. With respect to the histopathological evaluation, for the treatment with ethyl-cyanoacrylate, there was observed already in the very first periods of evaluation, corneal epitelization, collagen organization and moderate inflammatory reaction. For the octhyl-cyanoacrylate treatment, there was observed the adhesive permanence until later phases, under which more vagarously the events of reepithelization and collagen organization occurred with a discrete inflammatory reaction. The ethyl-cyanoacrylate presented minor costs and more facility to acquire.
Mestre
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Costa, Dacio Carvalho. "Uso de triancinologia subconjuntival no tratamento da rejeição endotelial do transplante de cornea." [s.n.], 2009. http://repositorio.unicamp.br/jspui/handle/REPOSIP/311490.
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Orientador: Newton Kara-JoseTese (doutorado) - Universidade Estadual de Campinas, Faculdade de Ciencias Medicas
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Resumo: Objetivo: Comparar a eficácia da injeção subconjuntival de 20 mg de triancinolona associada a prednisolona 1% tópica com a injeção intravenosa de 500 mg de metilprednisolona associada a prednisolona 1% tópica no tratamento da rejeição endotelial de transplante de córnea. Métodos: Estudo caso-controle realizado no Hospital das Clínicas da UNICAMP. Os pacientes submetidos a transplante penetrante de córnea que apresentaram primeiro episódio de rejeição endotelial com até 15 dias do início dos sintomas durante o período de novembro de 2005 a outubro de 2006 foram tratados com injeção subconjuntival de 20 mg de acetonido de triancinolona associado a acetato de prednisolona 1% tópico. Estes pacientes foram pareados por idade e diagnóstico com pacientes submetidos a tratamento com injeção intravenosa de 500 mg de succinato sódico de metilprednisolona associado a acetato de prednisolona 1% tópico e analisados quanto à capacidade de reversão do episódio de rejeição, pressão intraocular aos 30 dias e acuidade visual ao final de 1 ano. Resultados: 16 pacientes foram tratados com 20 mg de triancinolona subconjuntival e prednisolona 1% tópica durante o período de recrutamento e foram pareados com 16 pacientes tratados com 500 mg de metilprednisolona intravenosa e prednisolona 1% tópica. Ao final de 1 ano, o grupo tratado com triancinolona obteve melhores resultados do que o grupo tratado com metilprednisolona (p=0,025), obtendo 15 pacientes com córnea transparente enquanto o grupo tratado com metilprednisolona obteve 10 pacientes. 3 pacientes do grupo tratado com triancinolona apresentaram segundo episódio de rejeição durante o seguimento e foram retratados com sucesso enquanto no grupo da metilprednisolona, 4 pacientes apresentaram segunda rejeição, com 2 pacientes apresentando falência com o retratamento e 2 obtendo sucesso. A pressão intraocular subiu nos dois grupos (p=0,002) após 30 dias, porém não houve diferença entre os grupos (p=0,433). A acuidade visual melhorou após 1 ano em ambos os grupos (p=0,049) e o grupo tratado com triancinolona obteve melhor acuidade visual (p=0,002). Conclusão: A injeção subconjuntival de 20 mg de triancinolona combinada com prednisolona 1% tópica mostrou-se mais eficaz em reverter episódios de rejeição de transplante de córnea neste estudo caso-controle do que a aplicação intravenosa de 500 mg de metilprednisolona. Estudos adicionais necessitam ser realizados para verificar a segurança e eficácia deste tratamento em grandes populações
Abstract: Purpose: To compare the efficacy of 20 mg subconjunctival triamcinolone in association with topical prednisolone 1% to 500 mg intravenous methylprednisolone in association with topical prednisolone 1% in the treatment of cornea endothelial graft rejection. Methods: Case-control study carried out at State University of Campinas Hospital. Patients submitted to penetrating keratoplasty that presented first episode of corneal endothelial rejection within 15 days of symptoms onset between November 2005 and October 2006 were treated with 20 mg subconjunctival injection of triamcinolone acetate in association with topical prednisolone acetate 1%. These patients were matched for age and diagnosis to patients that were submitted to a single 500 mg intravenous injection of methylprednisolone sodium succinate in association with topical prednisolone acetate 1% and analyzed regarding the reversion of the rejection episode, intraocular pressure at day 30 and visual acuity at the end of 1 year. Results: 16 patients were treated with 20 mg subconjunctival triamcinolone and topical prednisolone 1% during the period of recruitment and were matched to 16 patients treated with 500 mg intravenous methylprednisolone and topical prednisolone 1%. At the end of 1 year, the group treated with triamcinolone had a better outcome than the group treated with methylprednisolone (p=0.025), having 15 patients with clear grafts as the group treated with methylprednisolone had 10 patients. 3 patients from the group treated with triamcinolone had new rejection episodes during follow-up and were retreated successfully as in the group treated with methylprednisolone 4 patients had a new rejection episode, with 2 progressing to failure and 2 to success with retreatment. Intraocular pressure rose in both groups (p=0.002) at day 30 but there were no statistically significant differences between the groups (p=0.433). Visual acuity improved after 1 year in both groups (p=0.049) and the group treated with triamcinolone had better visual acuities (p=0.002). Conclusions: 20 mg subconjunctival injection of triamcinolone acetonide associated with topical prednisolone acetate 1% showed to be more effective than 500 mg intravenous methylprednisolone associated with prednisolone acetate 1% in this case-control study. Further studies need to be accomplished to verify its safety and effectiveness in larger populations
Doutorado
Oftalmologia
Doutor em Ciências Médicas
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Lima, Mário Henrique Camargos de. "Avaliação da função visual de pacientes submetidos a transplante de córnea lamelar anterior profundo utilizando dissecção com fio." Universidade de São Paulo, 2015. http://www.teses.usp.br/teses/disponiveis/5/5149/tde-05012016-154155/.
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Objetivo: Avaliar a função visual de pacientes submetidos a transplante lamelar anterior profundo (DALK) utilizando a dissecção com tunelizador manual e fio. Métodos: Foram incluídos 33 pacientes com ceratocone que apresentavam BCVA <= 0,60 LogMar, miopia e astigmatismo entre 8,00 e 10,00D, K central médio > 53,00D, ausência de cicatrizes, espessura corneana mínima entre 300 e 400 um. Foi feita avaliação oftalmológica completa no pré e no pós-operatório de 6 a 8 meses. Estas avaliações foram complementadas com exame topográfico da córnea, microscopia especular para avaliação da densidade das células endoteliais corneanas, aberrometria corneana e exame de tomografia de coerência óptica do segmento anterior. As variáveis BCVA, UCBA e os valores totais das aberrações corneanas de alta ordem foram correlacionadas com a espessura do leito estromal residual. Resultados: Os pacientes submetidos à DALK apresentaram BCVA de 0,68 ± 0,27 LogMar o que representa BCVA superior a 20/40 em 60% da amostra analisada. Não foram observadas micro ou macroperfurações. Houve diminuição na contagem endotelial de 2702,87 ± 548,87 células por mm2 para 2282,10 ± 525,66 células por mm2 . A dissecção do estroma profundo com o fio facilitou a remoção de tecido estromal posterior, fato corroborado com o achado de que o leito residual estromal aferido foi de 49,18 ± 18,36 ?m na região central e foi inferior a 80 ?m em grande parte dos pacientes estudados. No que se refere à regularidade da dissecção, observou-se tendência a valores mais elevados de espessura residual na periferia (60,09 ± 17,70 ?m). Não houve correlação da BCVA, UCVA e do total de aberrações de alta ordem da córnea com a espessura do leito estromal residual. Conclusão: A apreciação dos resultados desse estudo mostrou que com a técnica utilizada para realização de DALK em portadores de ceratocone obteve-se resultados topográficos e funcionais semelhantes a outras técnicas consagradas pela literatura. A facilidade na dissecção do estroma profundo, a regularidade da dissecção e a presença de baixíssimo índice de conversão para transplantes penetrantes são encorajadoresObjective: Evaluate the visual function of patients undergoing deep anterior lamellar keratoplasty (DALK) using a manual spatula and a wire dissection. Methods: Thirty three keratoconus patients were included, meeting the following inclusion criteria: BCVA logMAR <=0,60, myopia and astigmatism between 8.00 and 10,00D, K central average > 53.00D, no corneal scars and minimal corneal thickness between 300 and 400 um. Complete ocular evaluation was performed preoperatively and postoperatively in 6-8 months. These assessments were supplemented by topographical survey of the cornea, specular microscopy to evaluate the density of corneal endothelial cells, corneal wavefront analysis and examination of optical coherence tomography of the anterior segment (Visante). The BCVA variables, UCVA and the total amounts of corneal higher-order aberrations were correlated with the the residual stromal bed thickness. Results: Patients that undergone to DALK with the described technique presented a BCVA of 0.68 ± 0.27 logMAR which represents a BCVA of more than 20/40 at 60% of the analyzed sample. There were no micro or macroperforations. We observed a small decrease in the endothelial cell count from 2702.87 ± 548.87 cells per mm2 to 2282.10 ± 525.66 cells per mm2. The dissection of the deep stroma with a wire facilitated the posterior stromal tissue removal, thus the measured stromal bed thickness was 49.18 ± 18.36 ?m in the central region and less than 80 ?m in the majority of the studied patients. As regards the dissection regularity, we showed a tendency to higher values of residual thickness at the periphery (60.09 ± 17.70 ?m). There was no correlation of the BCVA, UCVA and total corneal higher-order aberrations with the residual stromal bed thickness. Conclusion: The assessment of the study data showed that the described technique achieved a topographical and functional result similar to other techniques consecrated by literature. The shallow learning curve, the ease to perform the dissection of the deep stroma, the postoperative stromal regularity and the presence of very low conversion rate for penetrating keratoplasty are encouraging
Books on the topic "Cornea – Diseases"
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1919-, Grayson Merrill, ed. Grayson's diseases of the cornea. 3rd ed. St. Louis, MO: Mosby-Year Book, 1991.
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1919-, Grayson Merrill, ed. Grayson's diseases of the cornea. 4th ed. St. Louis, Mo: Mosby, 1997.
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Rapuano, Christopher J. Cornea. New York: McGraw-Hill Medical Pub. Division, 2003.
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A, Palay David, ed. Cornea color atlas. St. Louis: Mosby, 1995.
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Trattler, William B. Cornea handbook. Thorofare, NJ: SLACK Inc., 2010.
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Cornea handbook. Thorofare, NJ: SLACK Inc., 2010.
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1941-, Waring George O., ed. Corneal disorders: Clinical diagnosis and management. 2nd ed. Philadelphia: Saunders, 1998.
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Copeland, Robert A., Natalie A. Afshari, and Claes H. Dohlman. Copeland and Afshari's principles and practice of cornea. New Delhi: Jaypee-Highlights Medical Publishers, Inc., 2013.
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Ophthalmology, American Academy of, ed. External disease and cornea. San Francisco, CA: American Academy of Ophthalmology, 1998.
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Krachmer, Jay H. Cornea. 2nd ed. Philadelphia: Elsevier/Mosby, 2005.
Find full textBook chapters on the topic "Cornea – Diseases"
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Galloway, N. R. "Common Diseases of the Conjunctiva and Cornea." In Common Eye Diseases and their Management, 51–72. London: Springer London, 1985. http://dx.doi.org/10.1007/978-1-4471-3521-0_5.
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Galloway, Nicholas Robert, and Winfried Mawutor Kwaku Amoaku. "Common Diseases of the Conjunctiva and Cornea." In Common Eye Diseases and their Management, 41–54. London: Springer London, 1999. http://dx.doi.org/10.1007/978-1-4471-3625-5_6.
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Galloway, Nicholas R., Winfried M. K. Amoaku, Peter H. Galloway, and Andrew C. Browning. "Common Diseases of the Conjunctiva and Cornea." In Common Eye Diseases and their Management, 47–63. Cham: Springer International Publishing, 2016. http://dx.doi.org/10.1007/978-3-319-32869-0_6.
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Galloway, Nicholas R., Winfried M. K. Amoaku, Peter H. Galloway, and Andrew C. Browning. "Common Diseases of the Conjunctiva and Cornea." In Common Eye Diseases and their Management, 49–65. Cham: Springer International Publishing, 2022. http://dx.doi.org/10.1007/978-3-031-08450-8_6.
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Verbruggen, A. M., M. De Roo, E. De Clercq, R. Busson, R. Bernaerts, P. C. Maudgal, C. Ameye, and L. Missotten. "Permeability of the Cornea to (125I)IVDU, an Analogue of Bromovinyldeoxyuridine." In Herpetic Eye Diseases, 257–61. Dordrecht: Springer Netherlands, 1985. http://dx.doi.org/10.1007/978-94-009-5518-9_36.
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Verkman, Alan S. "Aquaporins and Water Transport in the Cornea." In Ocular Transporters In Ophthalmic Diseases And Drug Delivery, 3–16. Totowa, NJ: Humana Press, 2008. http://dx.doi.org/10.1007/978-1-59745-375-2_1.
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Jacob-LaBarre, Jean T., and Delmar R. Caldwell. "Development of a New Type of Artificial Cornea for Treatment of Endstage Corneal Diseases." In Progress in Biomedical Polymers, 27–39. Boston, MA: Springer US, 1990. http://dx.doi.org/10.1007/978-1-4899-0768-4_6.
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Harkin, Damien G., Allison J. Sutherland, Laura J. Bray, Leanne Foyn, Fiona J. Li, and Brendan G. Cronin. "The use of mesenchymal stromal cells in the treatment of diseases of the cornea." In The Biology and Therapeutic Application of Mesenchymal Cells, 524–43. Hoboken, NJ, USA: John Wiley & Sons, Inc., 2016. http://dx.doi.org/10.1002/9781118907474.ch36.
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"Cornea." In Inherited Eye Diseases, 47–118. CRC Press, 2005. http://dx.doi.org/10.1201/b14269-8.
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Kaiura, Terry L., Glenn L. Stoller, and George J. Florakis. "Inflammatory Bowel Disease and Other Systemic Inflammatory Diseases." In Cornea, 711–19. Elsevier, 2011. http://dx.doi.org/10.1016/b978-0-323-06387-6.00068-4.
Full textConference papers on the topic "Cornea – Diseases"
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Molladavoodi, Sara, John B. Medley, Maud Gorbet, and H. J. Kwon. "Mechanotransduction in Corneal Epithelial Cells." In ASME 2013 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/imece2013-65406.
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Mechanical properties of the cornea can be affected by diseases such as keratoconus. In keratoconus, a decrease in both thickness and rigidity of the cornea is observed. It is currently not clear whether and how changes in mechanical properties of the cornea are associated with corneal epithelial cell behavior. In the present study, polyacrylamide (PAA) gels with different elastic moduli have been prepared and human corneal epithelial cells (HCECs) have been cultured on them. To investigate the effect that changes in elastic modulus may have on adhesion and migration of corneal epithelial cells, actin filament organization and expression of adhesion molecules were characterized. It was found that HCECs actin filament organization improves with increasing substrate stiffness and integrin α3 expression significantly increases on more compliant substrates.
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Khan, Altaf, Zoujun Dai, and Thomas J. Royston. "Measuring and Modeling Elastography of Human Cornea Using Scanning Laser Doppler Vibrometry." In ASME 2013 Summer Bioengineering Conference. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/sbc2013-14566.
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Our interest is in noninvasively mapping the viscoelastic properties of the human cornea with the aid of a Scanning Laser Doppler Vibrometer (SLDV). Mechanical properties of the cornea can be used to predict early onset of diseases, such as glaucoma and keratoconus. By applying mechanical vibration near the cornea and measuring the dynamic wave propagation across the cornea, an elastographic map can be reconstructed. To effectively reconstruct the data, an appropriate analytical solution is needed to interpret the measured motion; in the present article, we review initial measurements and modeling of phantom cornea models. Several viscoelastic plate phantoms were constructed using silicone gels to simulate corneal structures. Comprehensive frequency sweeps were performed on these phantoms. The material can be represented using a fractional order model of viscoelasticity. Similar experiments have been completed on ex-vivo human cornea from donor eyes. The design shows proof of concept and is now being modified to a more applicable manner for in vivo experiments.
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Pinos, Eduardo, Roberto Coronel, and Maria Cordero. "Three-dimensional construction of the corneal geometry from tomographic images and biomechanical parameters of the cornea." In 13th International Conference on Applied Human Factors and Ergonomics (AHFE 2022). AHFE International, 2022. http://dx.doi.org/10.54941/ahfe1002692.
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Currently, there are various diseases that affect the corneal structure, when not treated in a timely manner can cause damage to the corneal structure, which affects the correct vision of people, in these cases the patient goes to the ophthalmologist, who through clinical studies determines the pathology and the degree of impairment of the corneal structure, in many cases surgery is necessary to correct this damage, however, there are cases in which after surgery the cornea suffers further damage to its structure, further affecting the visual acuity.To avoid damage after surgery, more effective methods are searched to determine whether the patient requires surgery or not, by analyzing the corneal biomechanics and its properties, in addition, the morphological analysis of the corneal tissue that allows observing the physical changes produced by these diseases. With the purpose of studying the physical structure and the forces applied on the corneal tissue, this article presents a construction of the corneal surface, for this, different types of elastic, hyperelastic and visco-elastic materials for simulation have been analyzed, whose characteristics resemble the flexible behavior of the corneal tissue in conditions of tension and deformation, in addition, a three-dimensional corneal geometry has been obtained from images of corneal tomographies, which were extracted from ophthalmologic examinations. Consequently, the unification of the three-dimensional geometry of the cornea with the properties of elasticity, Poisson's ratio and density assigned to a simulation material, results in a corneal model that resembles the natural corneal tissue.
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Schelokov, R. V., and V. V. Yatsishen. "Diagnostics of virus diseases of a cornea by ellipsometry methods." In SPIE Proceedings, edited by Valery V. Tuchin. SPIE, 2004. http://dx.doi.org/10.1117/12.578978.
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Khan, Altaf A., Zoujun Dai, Soledad Cortina, Wallace Chamon, and Thomas J. Royston. "Localized Elastography Map of Human Cornea Through Surface Vibrations." In ASME 2013 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/imece2013-64016.
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Elastography techniques are being developed to diagnose and monitor the progression and treatment of diseases that correlate with changes in soft tissue stiffness. The objective of this paper is to outline the application of vibrations to the human cornea in order to reconstruct a stiffness map. Having a localized stiffness map is useful for early diagnosis of cornea related diseases such as glaucoma and keratoconus. Experimental data was collected by directly vibrating the excised cornea axisymetrically along the edge and measuring wave propagation inward with the use of laser vibrometry. Different methods have been implemented to increase the reflectivity of the cornea for laser vibrometry. To corroborate the data, as well as to test feasibility, experiments have been done on phantoms constructed from silicone-based polymers. To reconstruct the data into a stiffness map, an appropriate analytical model has to be derived. This paper outlines the derivation of the analytical model for the cornea starting with simple circular plates and moving towards the curved geometry of the cornea. To verify the analytical model, finite element simulations were used to replicate the results. These results have also been checked against experimental data to help determine any external variables that affect results. Overall, the feasibility and application of a process has been determined. Future goals include increasing in-vivo application to make the process safe and cost-effective.
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Zhang, Li, Willem F. Wolkers, and Alptekin Aksan. "Thermal Damage Distribution in Human Cornea Following Thermal Keratoplasty: An FTIR Study." In ASME 2007 Summer Bioengineering Conference. American Society of Mechanical Engineers, 2007. http://dx.doi.org/10.1115/sbc2007-176239.
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Hyperopia (farsightedness) and presbyopia are two common eye diseases, especially seen in the elderly. In both cases, eyes lose the ability to focus on nearby objects due to change in the cornea shape or stiffening of the lens. In recent years, thermal treatment of cornea in the form of Conductive Keratoplasty (CK) procedures has been successfully utilized to reshape the cornea. In the CK treatment, a thin radiofrequency (RF) probe is inserted into the cornea and heat is delivered into the stroma [1]. The heat treatment causes collagen denaturation and mechanical shrinkage of the collagen fibers. In the CK treated region, the collagen fibers are aligned in a circular fashion. Therefore, the shrinkage of these fibers steepens the curvature of the cornea. The amount of heat delivered to the stroma during CK treatment can be controlled either by changing the applied RF power or the heating time. In this study, we utilized Fourier Transform Infrared Spectroscopy (FTIR) to map the thermal damage distribution in the human cornea tissue following simulated CK treatment.
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Szabo, T. "FRAGMENTATION OF CERULOPLASMIN BY THROMBINF." In XIth International Congress on Thrombosis and Haemostasis. Schattauer GmbH, 1987. http://dx.doi.org/10.1055/s-0038-1644663.
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Copper containing proteolytic fragments of ceruloplasmin (CP), a 135 KDα2 -glycoprotein, have been shown to induce angiogenesis in the rabbit cornea assay.Neovascularisation plays an important role in different biological phenomena including chronic inflammation, wound healing, recanalisation of occluded blood vessels, tumor growth etc. Most of these events are associated with elevated CP levels. Neovascularisation occurs in diabetic macro- and microangiopathies as well. Serum CP concentrations in 92 diabetics were measured and compored to 50 healthy blood donors and 50 unselected hospitalized patients without malignancies. A marked CP elevation was observed in diabetics, especially in those with vascular complications. There was no correlation between the CP and the actual blood glucose concentrations, duration of the disease of the type of the treatment. Activation of the haemostatic processes has been found in the majority of diabetic patients with vascular diseases. In case CP is a substrate for thrombin, the generation of this specific serine protease may lead to the release of angiogenic peptides from CP on the site of vascular occlusion. For this reason, purified human CP was incubated with thrombin at pH 7.4, 37×C, and samples were removed at 0, 30, 60, 120, 240, min., and\after 2k hours for CP oxidase activity measurements and for SDS PAGE. Thrombin treatment did not affect the enzymic activity of CP. On SDS PAGE the band corresponding to the parent molecule eventually disappeared, and a Mr ll6 KD fragment together with three smaller peptides has been produced, with molecular masses 61, 4l and 20 KD, respectively. Based on these experiments, CP is to be considered as a new protein substrate for thrombin. The physiological relevance of this phenomenon needs further examination.
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Shafahi, Maryam, and Parham Piroozan. "Model of Drug Delivery to the Eye." In ASME 2014 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2014. http://dx.doi.org/10.1115/imece2014-39438.
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Ocular diseases cause vision deficiency and blindness in a substantial number of people in the world every day. Therefore, a controlled and sustained system of drug delivery to a specific spot within the eye is of interest for the ophthalmology community. The unique and complicated anatomy, physiology, and biochemistry of the eye make this organ highly resistant to drug delivery systems. The major challenge is to improve the efficiency of each treatment method along with avoiding the invasive techniques which damage the eye’s protective barrier tissues. In this work we make a computer model for the drug delivery to the anterior sections of the eye and provide a summary of transport characteristics of the eye, pharmacokinetics and efficacy of the utilized drugs. A two dimensional finite element model is utilized to solve the conservation of mass and momentum equations within different eye sub-domains such as cornea, anterior chamber, iris and sclera. The commercial software Comsol Multiphysics was utilized to obtain the profile of concentration in the eye and the grid independency of the numerical results has been checked. The results are being shown in terms of transient drug concentration profile in the eye subdomains. The influence of the modeling parameters on the efficiency of the drug delivery system is studied. The effect of physical variables such as drug molecular size and its bioavailability are investigated. The results are compared with the available literature data which are based on the drug diffusion within the domain.
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Tareq HAMMOODI, Zeyad. "CORONA EPIDEMIC (COVD 19) BETWEEN SHARIA AND MEDICINE." In International Research Congress of Contemporary Studies in Social Sciences (Rimar Congress 2). Rimar Academy, 2021. http://dx.doi.org/10.47832/rimarcongress2-7.
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The Corona epidemic is a wide group of viruses that include viruses that can cause a group of illnesses in humans, ranging from the common cold to severe acute respiratory syndrome, as there is no definitive and specific treatment for the epidemic. The medicines used are helpful and supportive, and they mostly aim to reduce the patient’s temperature with the use of pulmonary resuscitation devices, as the body’s resistance depends on autoimmunity, as it is the main factor in preventing this epidemic, and here we must know the role of medical and forensic scholars in preventing and treating With what appears from this epidemic and other epidemics, we do not know when and how they will appear to the world. The emergence of this disease is an extension of several diseases before it and the so-called (contemporary diseases), which are contagious communicable diseases, including bird flonza disease, swine flonza, sass and AIDS, mad cow disease, Ebola, human papillomavirus, herpes simplex virus, yellow fever, and many others These diseases are epidemic.
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"Neurological symptoms of corona virus disease." In 4th International Conference on Biological & Health Sciences (CIC-BIOHS’2022). Cihan University, 2022. http://dx.doi.org/10.24086/biohs2022/paper.836.
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Corona virus disease is an infectious disease induced by a family of viruses that can cause common cold and severe acute respiratory syndrome (SARS).This research work was designed to shed light on the different presentation forms, especially the unusual ones of the disease as an attempt to make early diagnosis for better and efficient treatment and prevention of the disease.A sample of 203 subjects who have had corona disease were questioned about the symptoms they were complaining of during the illness. Correlation coefficient study was conducted to declare the relationship between the different symptoms especially the unusual ones and the disease, among the symptoms themselves, certain symptoms with the age group, as well as the gender.The results showed positive correlation between many of the usual symptoms and the disease for instance, fever, headache, cough, dyspnea, malaise, muscle and joint pain, dizziness, loss of smell and appetite, running nose, sore throat, nausea, vomiting, and diarrhea. No significant correlation could be detected with the unusual symptoms like, elevated blood pressure, conjunctival congestion, amnesia, and decreased concentration, skin rash, loss of consciousness, intestinal colic and gastric pain.According to the available results no specific symptom could be attributed to a given age group or gender with the exception of the neurological symptoms in the form of amnesia, loss of consciousness, and decreased concentration. These findings were found to be firmly correlated with the severity of fever. The authors postulate that these symptoms can be attributed to the temporary reduction in the number of neurotransmitters molecules of the brain. Further work is needed to provide evidence in support of this postulation. In conclusion, for early diagnosis and therefore to achieve efficient treatment of corona disease, unusual presentation must be kept in mind. Fever must be delt with seriously and effectively to prevent or minimize the development of neurological symptoms. Using all means of audio, video, and social media to spread the information about the disease will have a crucial role in slowing the spread of the disease especially the new strains.
Reports on the topic "Cornea – Diseases"
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Wise, Kiersten. Fungicide Efficacy for Control of Corn Diseases. United States: Crop Protection Netework, February 2019. http://dx.doi.org/10.31274/cpn-20190620-002.
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Wise, Kiersten, and Purdue Extension. Corn Disease Management: Tar Spot. United States: Crop Protection Netework, February 2019. http://dx.doi.org/10.31274/cpn-20190620-008.
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Wise, Kiersten, Bob Kemerait, Trey Price, and Tom Allen. Spots on corn: Disease or something different? United States: Crop Protection Network, July 2021. http://dx.doi.org/10.31274/cpn-20210721-0.
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Nicholson, Ralph, Reuven Reuveni, and Moshe Shimoni. Biochemical Markers for Disease Resistance in Corn. United States Department of Agriculture, May 1996. http://dx.doi.org/10.32747/1996.7613037.bard.
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The objective was to screen maize lines for their ability to express resistance based on biochemical traits. Cultivars were screened for retention of the hydroxamic acid DIMBOA and the synthesis of phenols (based on anthocyanin production) as markers for resistance. Lines were selected and inoculated with fungal pathogens (Exserohilum turcicum, Puccinia sorghi, Cochliobolus heterostraphus, Colletotricum graminicola.), and the Maize Dwarf Mosaic and Johnson Grass Mosaic viruses. Lines were screened in the field and greenhouse. Results showed that lines selected for augmented phenol synthesis do exhibit heightened levels of resistance to fungal pathogens. Isolation of mRNA followed by northern analyses for expression of A1 (dihydroflavanol reductase) and peroxidase confirmed that genes for these enzymes were turned on in response to inoculation of lines predicted to exhibit resistance. Peroxidase and b-1,3-glucanase were assayed in breeding lines having or lacking the se gene. A specific ionically-bound peroxidase isozyme and a b-1,3-glucanase isozyme were revealed in lines having the se gene. Data suggest that peroxidase and b-1,3-glucanase isozymes, may be considered as markers to identify resistance to E. turcicum in maize genotypes with the se gene.
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Malvick, Dean, Tamra Jackson-Ziems, and Alison Robertson. Corn Disease Management: Goss’s Bacterial Wilt and Blight. United States: Crop Protection Netework, August 2018. http://dx.doi.org/10.31274/cpn-20190620-003.
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Webster, Richard W., Maxwell O. Chibuogwu, Hannah Reed, Brian Mueller, Carol L. Groves, Albert U. Tenuta, Martin I. Chilvers, Kiersten A. Wise, and Damon Smith. Disease Development and Deoxynivalenol Accumulation in Silage Corn. United States of America: Crop Protection Netework, November 2021. http://dx.doi.org/10.31274/cpn-20211130-000.
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Munkvold, Gary P., Charlie Martinson, and John M. Shriver. Fungicidal Control of Leaf Diseases in High-Oil Hybrid Corn, 2000. Ames: Iowa State University, Digital Repository, 2001. http://dx.doi.org/10.31274/farmprogressreports-180814-242.
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Munkvold, Gary P. Stalk and Ear Diseases in Bt and Non-Bt Corn Hybrids, 2000. Ames: Iowa State University, Digital Repository, 2001. http://dx.doi.org/10.31274/farmprogressreports-180814-104.
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Esker, Paul, and Forrest W. Nutter. Population Dynamics of Corn Flea Beetles and their Importance for Stewart’s Disease of Corn. Ames: Iowa State University, Digital Repository, 2004. http://dx.doi.org/10.31274/farmprogressreports-180814-618.
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Nutter, Forrest W., Blucher Menelas, and Paul Esker. Using Seed and Foliar Insecticides to Control Corn Flea Beetles and Stewart's Disease of Corn. Ames: Iowa State University, Digital Repository, 2003. http://dx.doi.org/10.31274/farmprogressreports-180814-10.
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