Microbial contamination of contact lenses is a significant risk factor leading to adverse responses. Adhesion of microorganisms to a contact lens is the first step in a series of events that leads to contact lens-related infections or inflammation. Recently, some of the non-steroidal anti-inflammatory drugs (NSAIDs) have been shown to have the ability to interfere with microbial biofilm formation. In this project, antibacterial properties of commonly used NSAIDs (salicylic acid, sodium diclofenac and ketorolac) were assessed and characterised using biological assays and molecular biological techniques. Salicylic acid, ketorolac and diclofenac reduced adhesion of a range of bacterial species isolated from corneal infection and inflammatory events to contact lenses in a dose-dependent manner. Salicylic acid also decreased the adhesion of Pseudomonas aeruginosa and Staphylococcus epidermidis to human corneal epithelial cells in a dose-dependent manner. Results further demonstrated that NSAIDs had a significant impact on the production of virulence factors such as Type IV pili mediated (twitching) motility, flagella mediated swimming, elastase, protease IV and alkaline protease and affected the production of acylated homoserine lactones of P. aeruginosa. Salicylic acid and ketorolac affect the expression of P. aeruginosa outer membrane proteins. In the presence of the salicylic acid and ketorolac more than 85% of all detectable outer membrane proteins changed and most were down-regulated. Moreover, in the presence of salicylic acid at least five gene products, including Na+ - translocating NADH (Nrq1), choline dehydrogenase (CHDH), a hypothetical protein of unknown function, a gene product with no similarity to any known sequence in the database and a sequence similar to 23S rRNA of P. aeruginosa, were down-regulated. The results of this study clearly demonstrated that NSAIDs have a significant impact on virulence factors and the expression of acylated homoserine lactones by P. aeruginosa. This thesis has illustrated the potential of NSAIDs for preventing bacterial contamination of contact lenses by ocular pathogens and highlights the potential for NSAIDs as antibacterial agents. Therefore, this class of compound should be investigated further for their therapeutic efficacy in vivo.

This survey research systematically collects Information on the long term effects of Irlen tinted lenses, from a specific diagnosed scotopic sensitive population. The survey used is based on Whiting's survey (1988), with variations and extensions made to increase information attained. Although the main focus of the survey is reading and related academic skills, other areas presenting new directions for further research, have also been included. 306 diagnosed scotopic sensitive Individuals, who had been using prescribed Irlen tinted lenses for a minimum of six months, were surveyed. 82.8 percent of the respondents indicated that they (or their child) had experienced great benefits from wearing Irlen tinted lenses. 70.1 percent Indicated that the greatest benefit had been in the area of reading. Cross-tabulations were made with length of time wearing the lenses, gender, and whether the respondent was filling in the questionnaire for themselves or for their child. The results of this descriptive research support Whiting's (1988), earlier findings. A review of the available literature and the Implications of these findings are discussed.

Syfte: Syftet med denna studie var att jämföra den initiala komforten mellan sfäriska och asfäriska stabila linser då uppfattningen har varit att asfäriska linser (med sin mer följsamma passform) borde vara bekvämare. Metoder: Studien omfattade 30 deltagare med en medelålder på 26 år. Med hjälp av topografens (Topcon CA-100) kontaktlinstillpassningsprogramvara valdes en sfärisk A- design lins (från Nordiska Lins) och en asfärisk A90 lins (från Expert Optik, Sverige) ut med passande parametrar. Linserna sattes i vardera öga utan att försökspersonen visste vilken lins som var vilken. Efter 5 respektive 15 minuter fick patienten, med hjälp av en modifierad VAS-skala, avgöra hur linserna kändes både i höger och vänster öga. Resultat: Ingen signifikant skillnad i komforten mellan de asfäriska och sfäriska linserna varken observerades efter 5 (p=0,78) eller 15 (p=0,84) minuter. Överlag ökade komforten både för de asfäriska och för de sfäriska linserna efter att de suttit i en stund; komforten ökade med 0,9 enheter för de asfäriska respektive 1,1 enheter för de sfäriska linserna mellan 5 och 15 minuters bärtid. Det fanns en signifikant skillnad i komfort för den enskilda asfäriska linsen mellan första och andra graderingstillfället (p=0,015) och samma gällde de sfäriska (p=0,0001). Slutsats: Resultatet visar ingen markant skillnad i initial komfort på stabila linser med dessa olika typer av designer; en multikurvig asfärisk samt en trekurvig sfärisk lins. Med detta i åtanke behöver man inte, ur ett komfortmässigt perspektiv, ta hänsyn till den specifika designen vid tillpassning med moderna stabila linser.

Durante las últimas décadas, la construcción de anillos de almacenamiento de electrones exclusivamente dedicados a la producción de radiación sincrotrón ha sido la clave para justificar el gran desarrollo de los componentes ópticos para rayos X. Se requieren nuevos elementos ópticos para una explotación óptima de las propiedades de esta luz, que puede usarse para descubrir los secretos de la materia y para revelar el mundo microscópico. El uso de radiación sincrotrón como sonda ha hecho posible una gran cantidad de experimentos para expandir el conocimiento de muchas áreas científicas. Paulatinamente, la radiación sincrotrón se ha convertido en un instrumento indispensable para muchos científicos, que trabajan en disciplinas muy diferentes como la biología, la química, la ciencia de materiales o incluso la arqueología. La microscopía de rayos X ha emergido como técnica para observar estructuras que no son accesibles con microscopia óptica convencional, y que tiene ventajas respeto a la microscopía electrónica debido a la mayor longitud de penetración y a la sensibilidad química de la radiación X. La óptica de los microscopios de rayos X incluye componentes como las lentes zonales de Fresnel que se producen con técnicas de microfabricación. En este trabajo, se han fabricado lentes zonales de Fresnel utilizando distintas técnicas y se han testado en diversas Fuentes de Luz Sincrotrón. Describiremos en detalle las técnicas de micro- y nanofabricación que son necesarias para la producción de estos elementes, des de la litografía por haz de electrones a la transferencia del patrón a distintos materiales. En particular, presentamos lentes para rayos X blandos hechas de silicio. Mostraremos que éstas funcionan bien en las fuentes de luz existentes y que debido a su robustez serán también apropiadas para las fuentes de rayos X de 4a generación. También preparamos un elemento óptico difractivo que produce una mancha iluminación cuadrada y llana, y que puede usarse como lente condensadora en microscopía de rayos X de transmisión. Finalmente, también demostramos un nuevo método de fabricación que puede mejorar la resolución espacial última de las lentes difractivas para rayos X. Se fabricaron lentes zonales de Fresnel con una última zona de 20 nm y líneas de 15 nm han sido claramente resueltas en microscopía de rayos X de rastreo. Este trabajo se ha realizado en el Laboratorio de Luz Sincrotrón en Barcelona, con la participación del Centro Nacional de Microelectrónica de Barcelona (CSIC-CNM) y del Grupo de Óptica del Departamento de Física de la Universidad Autónoma de Barcelona. Al mismo tiempo, partes esenciales de este trabajo se han realizado con la colaboración del Dr. C. David y el Dr. K. Jefimovs del Labor fur Mikro- und Nanotechnologie al Paul Scherrer Institut en Villigen (Suiza). / During the last decades, the construction of electron storage rings exclusively dedicated to the production of synchrotron radiation has been a key reason to explain the large development of x-ray optics. New optical elements are required for an optimal exploitation of the properties of this light, which can be used to find out the secrets of matter and to reveal the microscopic world. The use of synchrotron light as a probe has made possible a large quantity of experiments to expand the knowledge in many scientific areas. Little by little, synchrotron radiation sources have become an indispensable tool for the research of lots of scientists, who work in very different disciplines such as biology, chemistry, physics, material science or even archaeology. X-ray microscopy has emerged as a technique to observe structures which are not accessible with conventional optical microscopy, and that has advantages in respect to electron microscopy due to the longer penetration depth and chemical sensitivity of the x-ray radiation. The optics of the x-ray microscopes includes components such as the Fresnel zone plate lenses which are made by means of microfabrication techniques. Within this work, Fresnel zone plate lenses were produced using different approaches and they have been tested in several Synchrotron Light Sources. We will describe in detail the micro- and nanofabrication techniques that are necessary for the production of such elements, from the electron beam lithography to the pattern transfer into different materials. In particular, we will present lenses for soft x-rays made of silicon. We show that they perform well at the current light sources and we think that due to their robustness they will also be suitable for the 4th generation x-ray sources. We also prepared a diffractive optical element which produces a square flat top illumination spot, and that can be used as a condenser lens in full-field transmission x-ray microscopy. Finally, we will also demonstrate a novel fabrication method which can push the ultimate spatial resolution of x-ray diffractive lenses. Fresnel zone plates with an outermost zone width of 20 nm have been fabricated and 15 nm lines have been clearly resolved in scanning transmission x-ray microscopy. This work has been carried out in the Laboratori de Llum Sincrotró in Barcelona, with the participation of the Centro Nacional de Microelectrònica de Barcelona (CSIC - CNM) and the Grup d'Òptica del Departament de Física de la Universitat Autònoma de Barcelona. At the same time, essential parts of this work have been done in close collaboration with Dr. C. David and Dr. K. Jefimovs from the Labor für Mikro- und Nanotechnologie at the Paul Scherrer Institut in Villigen (Switzerland).

The primary objective of this study was to quantify and characterise lipid deposition on soft (hydrogel) contact lenses, particularly those containing siloxane components. Studies involving a variety of <em>in vitro</em> doping and <em>in vivo</em> worn contact lenses were undertaken, in which lipid deposition was analyzed by either TLC or HPLC. Specific experiments were completed to optimize a method to extract the lipid from the lens materials, to compare the total lipid deposition on nine different hydrogel lenses and to analyze the effect that lipid deposition had on wettability. A method for extracting lipid from contact lenses using 2:1 chloroform: methanol was developed. This study also showed that siloxane-containing contact lens materials differ in the degree to which they deposit lipid, which is dependent upon their chemical composition. Small differences in lipid deposition that occur due to using variations in cleaning regimens were not identifiable through TLC, and required more sophisticated analysis using HPLC. Contact lens material wettability was found to be influenced by <em>in vitro</em> lipid deposition. Specifically, conventional hydrogels and plasma surface-treated silicone-hydrogel materials experienced enhanced wettability with lipid deposition. Reverse-phase HPLC techniques were able to quantify lipid deposits with increased sensitivity and accuracy. From the HPLC studies it was found that contact lens material, concentration of the lipid doping solution, and the composition of the lipid doping solution in <em>in vitro</em> deposition studies influenced the ultimate amount and composition of lipid deposits. <em>In vivo</em> HPLC studies showed that the final lipid deposition pattern was influenced by the interaction between the composition of the tear film and the various silicone hydrogel contact lens materials. In conclusion, HPLC analysis methods were more sensitive and quantitative than TLC. Lipid deposition was ultimately influenced by the concentration and composition of the lipid in the tear film and the contact lens material. Contact lens wettability was influenced by the presence and deposition of lipid onto the contact lens surfaces. Finally, this reverse-phase HPLC lipid analysis protocol was not the most sensitive, robust, or accurate. In the future, other methods of analysis should be explored.

The primary objective of this study was to quantify and characterise lipid deposition on soft (hydrogel) contact lenses, particularly those containing siloxane components. Studies involving a variety of <em>in vitro</em> doping and <em>in vivo</em> worn contact lenses were undertaken, in which lipid deposition was analyzed by either TLC or HPLC. Specific experiments were completed to optimize a method to extract the lipid from the lens materials, to compare the total lipid deposition on nine different hydrogel lenses and to analyze the effect that lipid deposition had on wettability. A method for extracting lipid from contact lenses using 2:1 chloroform: methanol was developed. This study also showed that siloxane-containing contact lens materials differ in the degree to which they deposit lipid, which is dependent upon their chemical composition. Small differences in lipid deposition that occur due to using variations in cleaning regimens were not identifiable through TLC, and required more sophisticated analysis using HPLC. Contact lens material wettability was found to be influenced by <em>in vitro</em> lipid deposition. Specifically, conventional hydrogels and plasma surface-treated silicone-hydrogel materials experienced enhanced wettability with lipid deposition. Reverse-phase HPLC techniques were able to quantify lipid deposits with increased sensitivity and accuracy. From the HPLC studies it was found that contact lens material, concentration of the lipid doping solution, and the composition of the lipid doping solution in <em>in vitro</em> deposition studies influenced the ultimate amount and composition of lipid deposits. <em>In vivo</em> HPLC studies showed that the final lipid deposition pattern was influenced by the interaction between the composition of the tear film and the various silicone hydrogel contact lens materials. In conclusion, HPLC analysis methods were more sensitive and quantitative than TLC. Lipid deposition was ultimately influenced by the concentration and composition of the lipid in the tear film and the contact lens material. Contact lens wettability was influenced by the presence and deposition of lipid onto the contact lens surfaces. Finally, this reverse-phase HPLC lipid analysis protocol was not the most sensitive, robust, or accurate. In the future, other methods of analysis should be explored.

Not available

Measurement of the quality and performance of soft contact lenses is not new and is continually evolving as manufacturing methods develop and more complicated contact lenses become available. Qualification of soft contact lenses has not been a simple task since they are fundamentally difficult to measure. The shape of the lens is extremely sensitive to how the lens is supported and the material properties can change quickly with time. These lenses have been measured in several different ways, the most successful being non-contact optical methods that measure the lens while it is immersed in saline solution. All of these tests measure the lens in transmission and do not directly measure the surface structure of the lens. The reason for this is that the Fresnel reflectivity of the surface of a contact lens in saline solution is about 0.07%. Surface measurements have been performed in air, but not in saline. The lens needs to be measured in solution so that it can maintain its true shape. An interferometer is proposed, constructed, verified, and demonstrated to measure the aspheric low reflectivity surfaces of a contact lens while they are immersed in saline solution. The problem is extremely difficult and requires delicate balance between stray light mitigation, color correction, and polarization management. The resulting system implements reverse raytracing algorithms to correct for retrace errors so that highly aspheric, toric, and distorted contact lens surfaces can be measured. The interferometer is capable of measuring both surfaces from the same side of the contact lens as well as the lens thickness. These measurements along with the index of refraction of the lens material are enough build a complete 3D model of the lens. A simulated transmission test of the 3D model has been shown to match the real transmission test of the same lens to within 32nm RMS or 1/20th of a wave at the test wavelength.

A device for performing an objective eye exam has been developed to automatically determine ophthalmic prescriptions. The closed loop fluidic auto-phoropter has been designed, modeled, fabricated and tested for the automatic measurement and correction of a patient's prescriptions. The adaptive phoropter is designed through the combination of a spherical-powered fluidic lens and two cylindrical fluidic lenses that are orientated 45° relative to each other. In addition, the system incorporates Shack-Hartmann wavefront sensing technology to identify the eye's wavefront error and corresponding prescription. Using the wavefront error information, the fluidic auto-phoropter nulls the eye's lower order wavefront error by applying the appropriate volumes to the fluidic lenses. The combination of the Shack-Hartmann wavefront sensor the fluidic auto-phoropter allows for the identification and control of spherical refractive error, as well as cylinder error and axis; thus, creating a truly automated refractometer and corrective system. The fluidic auto-phoropter is capable of correcting defocus error ranging from −20D to 20D and astigmatism from −10D to 10D. The transmissive see-through design allows for the observation of natural scenes through the system at varying object planes with no additional imaging optics in the patient's line of sight. In this research, two generations of the fluidic auto-phoropter are designed and tested; the first generation uses traditional glass optics for the measurement channel. The second generation of the fluidic auto-phoropter takes advantage of the progress in the development of holographic optical elements (HOEs) to replace all the traditional glass optics. The addition of the HOEs has enabled the development of a more compact, inexpensive and easily reproducible system without compromising its performance. Additionally, the fluidic lenses were tested during a National Aeronautics Space Administration (NASA) parabolic flight campaign, to determine the effect of varying gravitational acceleration on the performance and image quality of the fluidic lenses. Wavefront analysis has indicated that flight turbulence and the varying levels of gravitational acceleration ranging from zero-G (microgravity) to 2G (hypergravity) had minimal effect on the performance of the fluidic lenses, except for small changes in defocus; making them suitable for potential use in a portable space-based fluidic auto-phoropter.

There are many populations poorly served by the current Canadian approach to health and illness care. These populations include members of ethnic minority groups, those with poor socio-economic status, those who are homeless, working in the sex trade or affected by mental illness. One way of potentially improving the health of communities or populations is through policy. In addition, a deeper understanding of the health needs of underserved populations could facilitate expeditious solutions mindful of resource challenges. In spite of copious research, health inequities and disparities persist. My hypothesis was that the conscious use of specific lenses to examine policies or interview data was a useful device to both better visualize and understand actions related to policy development and community member input. Thus, this thesis research was comprised of two major components. The first was an exploration of two policies of an academic tertiary health care centre through the lenses of feminist, critical social and systems theory. The objective was to determine if viewing policy development using different lenses might influence thinking about issues related to underserved populations. The second component used the same three lenses to conduct a grounded theory analysis of eleven photo-elicitation and six photo-voice interviews with North End Halifax Community members. The focus of these interviews was on contributions to health found in the community of North End Halifax. The results clearly show that examination of policies through the three theoretical lenses serves to highlight hidden assumptions and to broaden the view and comprehension of implications and potential impacts of policies. A better way to formulate policies is one step towards achievement of improved health outcomes. The use of three lenses in the grounded theory analysis significantly enhanced the depth of interview analysis: the feminist lens accentuated the concept of caring and relationships and the extent of the White-middle-class male perspective; the critical social lens crystallized the power disparities at play; and the systems lens stressed the need to examine root causes. The conscious use of specific lenses could facilitate a more comprehensive and comprehended view of the health needs of underserved populations.