Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 1981. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND ENGINEERING. / Bibliography: leaves 59-62. / by John Luigi Battaglioli. / M.S.

Traditional methods of drug delivery to the eye include topical application, intraocular injection and systemic administration; however, each method has its limitation to efficiently delivery drugs to the back of the eye. In this study, microneedles were tested to provide targeted drug delivery into the eye in a minimally invasive way. To better interpret subsequent microneedle studies, we first quantified lateral drug diffusion profile within the sclera, by carrying out a diffusion study of a model compound, sulforhodamine, through human cadaver sclera, and developing a theoretical model for prediction of drug delivery kinetics and distribution. The results showed that measurable amounts of sulforhodamine were detected at distances of 5 and 10 mm from the sulforhodamine donor reservoir at 4 h and 3 days, respectively. The effective lateral diffusivity of sulforhodamine was determined to be 3.82 x 10-6 cm2/s, which is similar in magnitude to the transverse diffusivity. We next assessed the capability of using coated solid metal microneedles to deliver drugs into the ocular tissue in both in vitro and in vivo scenarios. The in vitro insertion tests showed that these microneedles were mechanically strong enough to penetrate into human cadaver sclera, and the coating solution rapidly dissolved off the needles after insertion and had been deposited within the tissue. In the in vivo experiments, microneedle delivery exhibited elevated fluorescein levels in the rabbit eye 60 times greater than that delivered by topical application of the equivalent dose. Similarly, microneedle delivery of pilocarpine caused rapid and extensive pupil constriction. Safety exams reported no inflammatory responses in the eye after microneedle administrations. We also used hollow glass microneedles to infuse solutions into the sclera tissue in vitro and examined the physiological barriers for flow. On average, 18 microliters of sulforhodamine solution and a solution containing nanoparticles was delivered into the sclera upon retraction of the microneedle. Successful delivery of micron-sized particles into the sclera could be improved by breaking down tightly packed collagen and GAG fibers using either collagenase or hyaluronidase.

Tracking gaze of an individual provides important information in understanding the behavior of that person. Gaze tracking has been widely used in a variety of applications from tracking consumers gaze fixation on advertisements, controlling human-computer devices, to understanding behaviors of patients with various types of visual and/or neurological disorders such as autism. Gaze pattern can be identified using different methods but most of them require the use of specialized equipments which can be prohibitively expensive for some applications. In this dissertation, we investigate the possibility of using sclera and iris regions captured in a webcam sequence to estimate gaze pattern. The sclera and iris regions in the video frame are first extracted by using an adaptive thresholding technique. The gaze pattern is then determined based on areas of different sclera and iris regions and distances between tracked points along the irises. The technique is novel as sclera regions are often ignored in eye tracking literature while we have demonstrated that they can be easily extracted from images captured by low-cost camera and are useful in determining the gaze pattern. The accuracy and computational efficiency of the proposed technique is demonstrated by experiments with human subjects.

Made available in DSpace on 2014-06-11T19:27:57Z (GMT). No. of bitstreams: 0 Previous issue date: 2011-03-18Bitstream added on 2014-06-13T20:57:20Z : No. of bitstreams: 1 candioto_cg_me_jabo.pdf: 1268753 bytes, checksum: 33fa5ad0387bc80fb30d39654299dced (MD5) / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / O bulbo do olho é uma parte do organismo pouco estudada e que carece de mais valores fisiológicos nas diversas espécies de animais. Neste sentido, o objetivo deste trabalho foi avaliar os cortes histológicos dos olhos de Falco tinnunculus (peneireiro-de-dorso-malhado), por meio da morfometria da córnea, retina, coróide e esclera. As aves eram adultas e de vida livre. Os resultados obtidos foram comparados entre machos e fêmeas e entre os olhos direito e esquerdo. Após enucleação dos olhos, os mesmos foram fixados em solução tamponada de formaldeído por 48 horas e posteriormente, descalcificados. Os olhos direitos foram cortados verticalmente (dorsoventral), e os esquerdos horizontalmente (temporonasal). Após inclusão em parafina, foram confeccionados cortes de 5m de espessura e corados pelas técnicas rotineiras de hematoxilina e eosina. Para a análise dos cortes, foram definidos e medidos, seis pontos (1 a 6) na retina, coróide e esclera, e três pontos referentes na córnea (A, B e C). Com um software de análise de imagens, avaliou-se a espessura em micrômetros da córnea total, e suas camadas (epitelial, “camada média”, endotelial), além da retina, coróide e esclera nos seus respectivos pontos pré-determinados. Na córnea as maiores espessuras foram na periferia (ponto A e C) e as menores na área central (ponto B). As comparações entre as médias foram feitas pelo teste de Tukey (p<0,05). Nas fêmeas a retina foi mais espessa que nos machos. O dados descritos no trabalho complementam os conhecimentos básicos da histomorfologia do olho de Falco tinnunculus necessários para avaliação de cortes histopatológicos / The bulb of the eye is not a well-studied part of the body and needs more physiological values for various animal species. In this manner, the objective of the study was to evaluate the histological eye Falco tinnunculus (commom kestrel), through measurements of the cornea, retina, choroid and sclera. The birds were adults from wild life. The results were compared between males and females and between the right and left eyes. After enucleation of the eyes, they were fixed in buffered formaldehyde for 48 hours and subsequently decalcified. The right eyes were cut vertically (dorsoventral), and left horizontally (temporonasal). After paraffin embedding, sections were prepared from 5m thick and stained using routine hematoxylin and eosin. For the analysis of the cuts, six points (1-6) in the retina, choroid and sclera, and three points on the cornea (A, B and C) have been defined and measured. With an image analyzing software, the corneal thickness and its layers (epithelium, middle layer, endothelial), were evaluated in total microns, as well as the retina, choroid and sclera in their respective pre-determined points. Corneal thickness was greater in the periphery (A and C) and lower in the central area (B). Comparisons between means were made using the Tukey test (p <0.05). In females retina was thicker than the males. The data described in the paper complement the basic knowledge of histomorphology eye Falco tinnunculus for the assessment of histopathology

Orientador: Karin Werther / Banca: Fabiano Montiani-Ferreira / Banca: Rosimeri de Oliveira Vasconcelos / Resumo: O bulbo do olho é uma parte do organismo pouco estudada e que carece de mais valores fisiológicos nas diversas espécies de animais. Neste sentido, o objetivo deste trabalho foi avaliar os cortes histológicos dos olhos de Falco tinnunculus (peneireiro-de-dorso-malhado), por meio da morfometria da córnea, retina, coróide e esclera. As aves eram adultas e de vida livre. Os resultados obtidos foram comparados entre machos e fêmeas e entre os olhos direito e esquerdo. Após enucleação dos olhos, os mesmos foram fixados em solução tamponada de formaldeído por 48 horas e posteriormente, descalcificados. Os olhos direitos foram cortados verticalmente (dorsoventral), e os esquerdos horizontalmente (temporonasal). Após inclusão em parafina, foram confeccionados cortes de 5m de espessura e corados pelas técnicas rotineiras de hematoxilina e eosina. Para a análise dos cortes, foram definidos e medidos, seis pontos (1 a 6) na retina, coróide e esclera, e três pontos referentes na córnea (A, B e C). Com um software de análise de imagens, avaliou-se a espessura em micrômetros da córnea total, e suas camadas (epitelial, "camada média", endotelial), além da retina, coróide e esclera nos seus respectivos pontos pré-determinados. Na córnea as maiores espessuras foram na periferia (ponto A e C) e as menores na área central (ponto B). As comparações entre as médias foram feitas pelo teste de Tukey (p<0,05). Nas fêmeas a retina foi mais espessa que nos machos. O dados descritos no trabalho complementam os conhecimentos básicos da histomorfologia do olho de Falco tinnunculus necessários para avaliação de cortes histopatológicos / Abstract: The bulb of the eye is not a well-studied part of the body and needs more physiological values for various animal species. In this manner, the objective of the study was to evaluate the histological eye Falco tinnunculus (commom kestrel), through measurements of the cornea, retina, choroid and sclera. The birds were adults from wild life. The results were compared between males and females and between the right and left eyes. After enucleation of the eyes, they were fixed in buffered formaldehyde for 48 hours and subsequently decalcified. The right eyes were cut vertically (dorsoventral), and left horizontally (temporonasal). After paraffin embedding, sections were prepared from 5m thick and stained using routine hematoxylin and eosin. For the analysis of the cuts, six points (1-6) in the retina, choroid and sclera, and three points on the cornea (A, B and C) have been defined and measured. With an image analyzing software, the corneal thickness and its layers (epithelium, "middle layer", endothelial), were evaluated in total microns, as well as the retina, choroid and sclera in their respective pre-determined points. Corneal thickness was greater in the periphery (A and C) and lower in the central area (B). Comparisons between means were made using the Tukey test (p <0.05). In females retina was thicker than the males. The data described in the paper complement the basic knowledge of histomorphology eye Falco tinnunculus for the assessment of histopathology / Mestre

Thesis (Ph. D.)--University of Oklahoma. / Bibliography: leaves 164-207.

Glaucoma is a blinding disease characterized by damage to the optic nerve and often caused by an increase in the intra-ocular pressure. Glaucoma affects from 2% to 8% of the South African population, depending on race and age. Primary Open-angle Glaucoma (POAG) is found mostly in patients above the age of 40 years. POAG is more prevalent in black people, with the number of black persons contracting the disease double that of persons of European origin. In South Africa, the prevalence of blindness is estimated to be 0,6%, thus 240 000 out of a total of 40 million. Glaucoma is responsible for an estimated 20% of the total number of blind people, thus approximately 48 000. The treatment of glaucoma in Africa, and particularly in rural areas, presents many unresolved problems. Conventional conservative treatment with eye drops is difficult, due to the following reasons: -- Logistical problems of providing patients with a supply of medication. -- Appropriate use of drops requires education, together with a high degree of personal compliance. -- Cost of medical treatment. Patients require life-long treatment. Eye drops cost approximately R100,00 per person per month. Thus, over a ten-year period, the cost would be R12 000,00 per person and R576 million for the estimated 48 000 sufferers. Conventional surgery is not very effective, due to the following reasons: -- Scarring takes place at the surgical site. -- Can be performed only in main centres with microsurgical facilities and competent staff. -- Requires travelling expenses, not only for surgery, but also for periodical follow-up examinations. -- Surgical complications are not uncommon. Conventional laser surgery is not effective, for the following reasons: -- Can be performed only in main centres with laser surgery facilities and competent staff. -- Requires travelling expenses, not only for surgery, but also for periodical follow-up examinations. -- Complications of surgery are not uncommon. This dissertation describes an investigation concerning treatment of glaucoma, with specific reference to the use of optical energy sources. The spectral transmission of the human sclera is investigated. Alternative methods of sourcing optical energy to the ciliary processes are presented and compared. Results obtained can be summarized as follows: -- The spectral transmission of the sclera was measured. -- Trans-scleral transmission was measured to be very low (less than 5%). The result was confirmed by means of histological investigation, where high scleral absorption was found. -- Since no well-defined transmission window could be found, the application source need not be monochromatic. -- Results published in literature were found to be inconsistent. / Dissertation (MEng (Bio-engineering))--University of Pretoria, 2006. / Electrical, Electronic and Computer Engineering / unrestricted

Made available in DSpace on 2015-07-22T20:49:32Z (GMT). No. of bitstreams: 0 Previous issue date: 2010-04-28 / O objetivo deste trabalho é avaliar as anormalidades da esclera, coroide e retina de coelhos induzidas pela dieta hipercolesterolêmica, além da possibilidade de prevenção dessas anormalidades com administração sistêmica de rosiglitazona. Para isto, 54 coelhos new zealand foram distribuídos em quatro grupos: grupo-controle (GC) recebeu dieta normal; grupo 1 recebeu dieta hipercolesterolêmica; grupo 2 recebeu dieta hipercolesterolêmica associada à administração diária de 3 mg de rosiglitazona a partir do 14º dia do início do experimento; e grupo 3 recebeu dieta hipercolesterolêmica associada à administração diária de 3 mg de rosiglitazona desde o início do experimento. Os coelhos foram pesados e submetidos à dosagem sérica de colesterol total, triglicerídeos, high density lipoprotein (HDL) colesterol e glicemia de jejum no início do experimento, no 14º dia e no momento da eutanásia (42º dia). A esclera e coroide foram submetidas à análise histológica e histomorfométrica. A retina foi submetida à análise imuno-histoquímica com o anticorpo monoclonal anticalretinina (CR) e anticorpo anti-glial fibrillary acidic protein (GFAP). Quando positivo para o marcador anticalretinina, duas análises quantitativas foram realizadas. Na primeira, foram contadas todas as células ganglionares imunorreativas. Na segunda, todas as células e elementos celulares imunorreativos foram avaliados pelo exame de morfometria de cores. Os dados foram analisados pelo teste nãoparamétrico de Kruskal-Wallis e teste de Shapiro-Wilks-Testand. Valores abaixo de 0,05 foram considerados estatisticamente significantes. Os resultados referentes ao peso demonstraram significativo aumento nos grupos 1 e 3 em relação ao GC no 14º dia (p<0,009), enquanto no 42º dia os grupos 1, 2 e 3 apresentaram representativamente mais peso que o GC (p<0,023). Quanto às variáveis laboratoriais, destacaram-se o aumento significativo da glicose e colesterol total de G1 em relação ao controle (p<0,001), assim como o acentuado aumento da HDL no G3 em relação aos demais grupos (p<0,001), no 14º dia. A HDL manteve-se expressivamente elevada no G3 em relação aos demais grupos no momento da eutanásia (p<0,001). À análise histomorfométrica da esclera e coroide obteve-se normalidade do GC. Por outro lado, o G1 mostrou marcante aumento da espessura da esclera e coroide em relação ao GC (p=0,008), enquanto que no G3 houve espessamento de esclera e coroide menor que no G1 (p=0,048). Elevado número de histiócitos foi observado na parede escleral do grupo submetido à dieta hipercolesterolêmica (G1), seguido de forma decrescente por G2, G3 e GC. A análise imuno-histoquímica da retina com o anticorpo monoclonal anticalretinina ressaltou número mais alto de células ganglionares imunorreativas no G1 que no G3 (p=0,002). O exame de morfometria de cores revelou significativa imunorreatividade das células e elementos celulares do G1 em relação aos outros grupos (p<0,001). Nesta análise evidenciou-se também acentuada imunorreatividade das células e elementos celulares de G2 e G3 em relação ao GC (p≤0,002). GFAP foi negativo em todos os grupos. Neste modelo, os achados permitem concluir que a hipercolesterolemia provoca anormalidades precoces histomorfométricas e imuno-histoquímicas do complexo esclerocoriorretiniano; e a ativação dos receptores do PPAR gama-ocular, a partir da dieta oral de rosiglitazona, foi efetiva em atenuar tais anormalidades nessas estruturas. / The purpose of this study is to evaluate scleral, choroid and retinal abnormalities in rabbits induced by a hypercholesterolemic diet and the prevention of these abnormalities after oral administration of rosiglitazone in rabbits. Fifty-four new zealand rabbits were divided into four groups: the control group (CG) was fed a normal diet; group 1 G1), a hypercholesterolemic diet; group 2 (G2) a hypercholesterolemic diet associated with daily administration of 3 mg of rosiglitazone from day 14 after the beginning of the diet; and group 3 G3), a hypercholesterolemic diet associated with daily administration of 3 mg of rosiglitazone since the beginning of the experiment. The rabbits were weighed and underwent the following examinations: seric dosages of total cholesterol, triglycerides, cholesterol HDL, and fasting glycemia at the beginning of the experiment, on the 14th day and on the 42nd, the euthanasia day. The sclera and choroid underwent histologic and histomorphometric analyses and the retina underwent immunohistochemical analysis with anti-calretinin (CR) and anti-glial fibrillary acidic protein (GFAP) antibody. When positive for the anti-calretinin marker, two quantitative analyses were performed. In the first analysis, all immunoreactive ganglion cells were counted. In the second analysis, all immunoreactive cells and cell elements were studied with the color morphometry method. The data were evaluated using the nonparametric Kruskal-Wallis and the Shapiro – Wilk tests. Values of p<0.05 were considered statistically significant. The results obtained showed a significant weight increase in Groups 1 and 3 in relation to CG on Day 14 (p<0.009). Additionally, a significant weight increase was observed in G1, G2 and G3 in relation to CG on Day 42 (p<0.023). The lab results showed a significant increase in glucose and total cholesterol in G1 in relation to CG (p<0.001) on Day 14, as well as a significant HDL increase in G3, when compared with the other groups (p<0.001) on Day 14. HDL in G3 was significantly high when compared to the other groups, on the euthanasia day (p<0.001). The results obtained regarding weight showed a significant increase in Groups 1, 2 and 3 in relation to CG on Day 14 (p<0.01) and Day 42 (p<0.02). The lab results showed a significant increase in glucose and total cholesterol in Groups 1, 2 and 3 in relation to CG (p<0.01) on Day 14, as well as a significant increase in HDL in G3 when compared with the other groups, on euthanasia day (p<0.01). The histomorphometric analysis of CG sclera and choroid presented normal results. Conversely, G1 showed a significant increase in sclera and choroid thickness in relation to CG (p= 0,008), whereas G3 showed thickness lower than in G1 (p=0,048). A larger number of histiocytes were observed on the scleral wall of the group that was fed the hypercholesterolemic diet (G1), followed, in a descending order, by groups 2 and 3, and the control group. The immunohistochemical analysis of the retina with the anti-calretinin monoclonal antibody showed that G1 presented a larger number of immunoreactive ganglion cells than G3 (p = 0.002). The color morphometry showed significant immunoreactivity of G1 cells and cell elements when compared with the other groups (p<0.001). A significant immunoreactivity of G2 and G3 cells and cell elements in relation to CG was also observed (p<0.002). GFAP results were negative in all groups. The findings of this proposed study model suggest that hypercholesterolemia induces early histomorphometric and immunohistochemical abnormalities in the sclerochorioretinal complex and that the activation of PPAR gamma in ocular cells attenuated these abnormalities with the administration of the oral rosiglitazone diet. / TEDE / BV UNIFESP: Teses e dissertações

Die Arbeit umreißt das Krankheitsbild der Myopie (Kurzsichtigkeit) und deren unterschiedliche Ausprägungen, im Speziellen der progressiven und pathologischen Myopie. Hierbei wird ein Einblick in die Symptomatik, die anatomischen Ursachen und die heutigen medizinischen Interventionen gegeben. Hierdurch wird die Problematik einer zu „weichen“ Sklera (Lederhaut des Auges) und des damit einhergehenden fortschreitenden Augenwachstums deutlich. Im Zentrum der Arbeit steht ein neuer therapeutischer Ansatz zur vorbeugenden Behandlung der pathologischen Myopie; das Riboflavin/Blaulicht Cross-Linking der Sklera des Kaninchenauges. Dessen Wirkungsweise ermöglicht die biomechanische Versteifung von kollagenem Gewebe. Aus diesem Sachverhalt ergibt sich die Fragestellung der Arbeit: Ist das sklerale Riboflavin/Blaulicht Cross Linking geeignet das Augenwachstum im Tiermodell (junge Kaninchen) verträglich zu hemmen? Operationsbeeinflussende Parameter wie die Riboflavin-Durchdringungsdauer der Sklera und die sklerale Lichtdurchlässigkeit werden untersucht und für die Optimierung der Operationsmethode herangezogen und diskutiert. Zur Einschätzung des Versuchsansatzes werden die im Methodikteil dargelegten Anwendungen an adulten und jungen Kaninchen/Kaninchenaugen durchgeführt. In Tierversuchen wird die Schadensschwelle in Abhängigkeit der Blaulichtintensität, des Alters und der Pigmentierung untersucht, wobei histologische, immunhistochemische und elektronenmikroskopische Verfahren angewendet werden. Der inhibitorische Einfluss des Riboflavin/Blaulicht Cross-Linkings auf das Augenwachstum kann im Jungtiermodell durch verschiedene metrische Verfahren und MRT-Untersuchungen belegt werden.

Background: Collagen cross-linking of the sclera is a promising approach to strengthen scleral rigidity and thus to inhibit eye growth in progressive myopia. Additionally, cross-linking might inhibit degrading processes in idiopathic melting or in ocular inflammatory diseases of the sclera. Different cross-linking treatments were tested to increase resistance to enzymatic degradation of the rabbit sclera. Methods: Scleral patches from rabbit eyes were cross-linked using paraformaldehyde, glutaraldehyde or riboflavin combined with UV-A-light or with blue light. The patches were incubated with collagenase I (MMP1) for various durations up to 24 h to elucidate differences in scleral resistance to enzymatic degradation. Degraded protein components in the supernatant were detected and quantified using measurements of Fluoraldehyde o-Phthaldialdehyde (OPA) fluorescence . Results: All cross-linking methods reduced the enzymatic degradation of rabbit scleral tissue by MMP1. Incubation with glutaraldehyde (1%) and paraformaldehyde (4%) caused nearly a complete inhibition of enzymatic degradation (down to 7% ± 2.8 of digested protein compared to control). Cross-linking with riboflavin/UV-A-light reduced the degradation by MMP1 to 62% ± 12.7 after 24 h. Cross-linking with riboflavin/blue light reduced the degradation by MMP1 to 77% ± 13.5 after 24 h. No significant differences could be detected comparing different light intensities, light exposure times or riboflavin concentrations. Conclusions: The application of all cross-linking methods increased the resistance of rabbit scleral tissue to MMP1-degradation. Especially, gentle cross-linking with riboflavin and UV-A or blue light might be a clinical approach in future.