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Objetivo: Estudar maneiras distintas de se corrigir a presbiopia durante a facoemulsificação, através da avaliação do desempenho visual de quatro diferentes modelos de lentes intraoculares; assim como determinar a influência da pupila na recuperação visual e comparar a independência ao uso de óculos após o implante bilateral. Casuística e Métodos: Estudo prospectivo, consecutivo, randomizado que avaliou 60 pacientes (120 olhos) divididos em quatro grupos: lentes multifocais Restor +3, Restor +2.5, monovisão com a lente SN60WF e a pseudoacomodativa Crystalens XO. Foram incluídos pacientes que apresentavam catarata nuclear NI, NII ou cortical similar, que foram submetidos à avaliação oftalmológica completa no pré- operatório e com 1, 3 e 12 meses após a cirurgia. Antes do procedimento, os seguintes exames foram realizados: biometria óptica (Lenstar 900), microscopia especular, avaliação da região macular e das camadas de fibras nervosas por meio de Tomografia de Coerência Óptica (OCT), avaliação da sensibilidade ao contraste (Software Macular Mapping Test) e pupilometria dinâmica (ISCAN INC). As cirurgias foram realizadas por dois cirurgiões, em caráter ambulatorial. Durante o seguimento, nas visitas de 1, 3 e 12 meses após a cirurgia, foram realizadas medidas de acuidade visual longe e perto, mono e binocular, curva de desfoco monocular e pupilometria; e foi aplicado um questionário de satisfação baseado do Visual Functioning Questionnaire - 25 (VFQ 25), assim como medidas de sensibilidade ao contraste. Resultados: Dos 120 olhos selecionados, 114 foram operados, 106 avaliados com um mês de cirurgia, 100 com três meses e 45 pacientes (90 olhos) chegaram a última avaliação com um ano de follow-up. As médias da acuidade visual para longe sem correção binocular foram de 0,09 ± 0,04; 0,09 ± 0,03 e 0,11 ± 0,03 logMar para as lentes Restor +2.5, Restor +3 e SN60WF, respectivamente. Entre elas não se observou diferença significativa. Já para a lente Crystalens XO, a média foi de 0,24 ± 0,04 logMar, constatando-se sua inferioridade para longe de forma significativa estatisticamente em relação às demais. Este resultado foi atribuído à pobre previsibilidade refracional da lente pseudoacomodativa (-1.33 ± 1.37 dpt). Para perto, não houve diferença entre os grupos Restor +3 e monovisão, e as lentes Restor +2.5 e Crystalens apresentaram piores resultados que as duas primeiras, de forma significativa. As médias para perto, em logMar foram de 0,08 ± 0,01; 0,17 ± 0,04; 0,22 ± 0,04 e 0,23 ± 0,07 para as lentes Restor +3, SN60WF, Restor +2.5 e Crystalens, respecivamente. A curva de desfoco das lentes multifocais Restor +3 e Restor +2.5 apresentou dois picos de acuidade visual máxima; o primeiro vértice próximo a zero e o segundo em -2.5 dpt para a Restor +3 e -2 dpt para a Restor +2.5. O segundo vértice da Restor +3 foi mais acentuado em relação ao da Restor +2.5. Já o modelo Crystalens apresentou a curva de desfoco com um pico de acuidade visual máxima, semelhante às lentes monofocais SN60WF, ambas com vértice próximo ao equivalente esférico programado. A partir da curva de desfoco, somando-se as acuidades visuais entre os dois picos de melhor visão, foi criado um índice, denominado Índice de Multifocalidade. O intuito foi criar um indicador de qualidade de visão longe, intermediário e perto para as diversas lentes. O modelo Restor +3 obteve o melhorResumo índice entre as lentes estudadas, porém não mostrou diferença significativa em relação à Restor +2.5, que, por sua vez, não evidenciou diferença quanto à Crystalens. A lente SN60WF teve o pior índice. Já em relação a pupila, não houve interferência de sua amplitude de contração no pré-operatório com as acuidades visuais longe e perto após a cirurgia. Contudo, o tamanho da pupila contraída demonstrou correlação com o índice de multifocalidade. A avaliação da sensibilidade a estímulos de baixo contraste (10%) no campo visual central (8 graus) não foi diferente entre os grupos, tanto no pré quanto no pós-operatório. E em relação à presença de halos e glare, os grupos Restor +3 e +2.5 apresentaram incidência de 26% e 43%, respectivamente; já no grupo SN60WF não houve relato. A satisfação com a performance visual para longe foi de 78% no grupo Crystalens, 80% no grupo monovisão e 90% para as multifocais Restor +3 e Restor +2.5. Para perto, 100 % dos usuários da Restor +3, 80% da monovisão, e 50% dos grupos Restor +2.5 e Crystalens estavam satisfeitos. Finalmente, entre as maneiras distintas de se corrigir a presbiopia na facoemulsificação, o grupo Restor +3 atingiu 93% de independência do uso de óculos após a cirurgia. Inesperadamente e de acordo com os resultados, o modelo Restor +2.5 demonstrou baixa probabilidade de independência (14%). Para a monovisão e Crystalens, 30% e 50%, respectivamente. Conclusões: Tanto a lente multifocal Restor +3 quanto a monovisão com a SN60WF foram eficazes de forma semelhante na correção da presbiopia, porém o modelo Restor +3 proporcionou maior probabilidade de independência ao uso de óculos. Os modelos Restor +2.5 e a Crystalens XO pseudoacomodativa foram inferiores que as duas primeiras, pela lente multifocal Restor +2.5 apresentar resultados aquém do previsto para perto, com baixa independência do uso de óculos; e a Crystalens mostrar imprevisibilidade refracional biométrica, comprometendo a visão de longe dos usuários. A respeito da dinâmica pupilar, as medidas do pré e pós-operatório não evidenciaram interferência no desempenho visual das lentes multifocais, monovisão e pseudoacomodativa; exceto no índice de multifocalidade, onde as pupilas contraídas apresentaram correlação com os resultados. / Objective: Study different ways of correcting presbyopia in phacoemulsification by comparing visual performance of four different models of intraocular lenses; as well as to determine the influence of the pupil on visual recovery and to compare the independence of glasses after bilateral implant. Casuistic and Methods: Prospective, consecutive, randomized study with 60 patients (120 eyes) divided into 4 groups: Restor +3 and Restor +2.5 multifocal lenses, monovision with SN60WF and Crystalens XO pseudoacommodative lens. Patients who had nuclear NI, NII or similar cortical cataract were submitted to a complete ophthalmologic evaluation in the preoperative period and at 1,3 and 12 months after surgery. Before procedure, the following tests were performed: optical biometry (Lenstar 900), specular microscopy, analyse of macular region and nerve fiber layers with Optical Coherence Tomography (OCT), contrast sensitivity (MMTest Software) and pupilometry dynamics (ISCAN INC). Surgeries were performed by two surgeons. During the follow-up, visits of 1, 3 and 12 months were measured far and near, mono and binocular visual acuity, defocous curve, pupilometry, satisfaction questionnaire was applied based on Visual Functioning Questionnaire - 25 (VFQ 25) as well as a contrast sensitivity measurements (Macular Mapping Test). Results: Of the 120 eyes selected, 114 were operated, 106 were evaluated at 1 month of surgery, 100 at 3 months, and 45 pacients (90 eyes) achieve the last evaluation at 1 year follow-up. The mean visual acuity for far without binocular correction was 0.09 ± 0.04; 0.09 ± 0.03 and 0.11 ± 0.03 logMar for the lenses Restor +2.5, Restor +3 and SN60WF respectively. Between them there was no difference. For the Crystalens XO lens, the mean was 0.24 ± 0.04 logMar, showing its inferiority statistically significantly different than the others. This result was attributed by the poor refractive predictability of the pseudoacommodative lens (-1.33 ± 1.37 dpt). For close, there was no difference between the Restor +3 and monovision groups, and the Restor +2.5 and Crystalens lenses were worse than the first with statistical significance . The means for near were 0,08 ± 0,01; 0.17 ± 0.04; 0.22 ± 0.04 and 0.23 ± 0.07 for the Restor +3, SN60WF-, Restor +2.5 and Crystalens lenses. The defocous curve of the multifocal lenses Restor +3 and Restor +2.5 had 2 peaks of maximum visual acuity, the first in zero and the second close to -2.5 dpt for Restor +3 and -2 dpt for Restor +2.5. The second vertex of Restor +3 was more pronounced than Restor +2.5. The Crystalens group presented a defocous curve with only 1 peak of maximum visual acuity, as well as the SN60WF monofocal lenses, both with a vertex near the programmed spherical equivalent. From the defocous curve, adding the visual acuity between the two best view peaks, an index was created, called Multifocality Index. The aim was to create a far, intermediate and close quality index for the various lenses. Restor +3 obtained the best index, but that was no significantly different than Restor +2.5, which had no difference with Crystalens. SN60WF achieved the worst index. Regarding the pupil, did no notice interference of its preoperative contraction amplitude with the visual acuities far and near after the surgery. However, the size of contracted pupil had a statistically significant correlation with the multifocality index. The sensitivity to low contrastAbstract stimuli (10%) in the central visual field (8 degrees) was no different between the groups, both in the pre and postoperative periods. About presence of halos and glare, the multifocal lenses Restor +3 and Restor +2.5 showed 26% and 43% respectively. No cases were reportaded with model SN60WF. The satisfaction with the far visual performance was 78% in the Crystalens group, 80% for monovision and 90% in the multifocal lenses Restor +3 and +2.5. For near, 100% of Restor +3 users, 80% of monovision, and 50% of Restor +2.5 and Crystalens groups were satisfied. Finally, among the distinct ways of correcting presbyopia in phacoemulsification, the Restor +3 group showed that 93% of their users achieved independence of the glasses after surgery. Unexpectedly and according to the visual results, the Restor +2.5 model showed a low probability of independence, 14%. For monovision and Crystalens, 30% and 50% respectively. Conclusions: Both Restor +3 and monovision with SN60WF were similarly effective for correction of presbyopia, but the Restor +3 model provides a greater probability of independence from wearing glasses. The Restor +2.5 and pseudoacommodative models Crystalens XO were worst than the first two, because the multifocal Restor +2.5 presented results below the predicted for near, with low independence of the use of glasses; and model Crystalens unexpected biometric refractive unpredictability, compromising the view from far away from users. Regarding the pupillary dynamics, the pre and postoperative measurements showed no interference in the visual performance of multifocal, monovision and pseudoacommodative lenses; except in the multifocality index, where pupils contracted had a correlation with the results.

Thesis advisor: Krzysztof Kempa / Though nature provides a plethora of materials to work with, their properties are very much restricted, forcing severe limitations on the devices that are built from them. A huge portion of current technology stands to be significantly advanced and even revolutionized by the emergence of a new class of “configurable” materials. This class, generally referred to as metamaterials, has become more feasible than ever due to advancements in nanotechnology and fabrication techniques. Notable among nature’s limitations is an ever-positive index of refraction. This barrier has only recently been broken, and the known paths to negative refraction are few and limited. This paper introduces two distinct three-dimensional crystals capable of all-angle negative refraction. One uses the familiar photonic band, while the other is the first of its kind to rely on polaritonic waves. Their mode structures are examined and a set of parameters are chosen at which a negative effective index of refraction can be harnessed for unrestricted sub-wavelength lensing, demonstrated via numerical simulation. This work is expected to enable experimental observation of polaritonic negative refraction and sub-wavelength lensing at microwave frequencies. / Thesis (BS) — Boston College, 2009. / Submitted to: Boston College. College of Arts and Sciences. / Discipline: College Honors Program. / Discipline: Physics.

Nesta trabalho estudamos o efeito de refração não linear em cristais fluoretos dopados com Cr+3 e polímeros. Tais cristais fluoretos têm recebido bastante atenção dos pesquisadores por apresentarem um espectro de emissão de banda larga e ação laser sintonizável na região de aproximadamente 780-1010 nm. Aplicando a técnica de lente Térmica (LT), realizamos um estudo quantitativo do comportamento da eficiência quântica de emissão, na presença dos processos de supressão térmica da fluorescência e conversão ascendente. Apresentamos um novo método de aplicação da técnica de LT, que possibilita a determinação da eficiência quântica em função do parâmetro de saturação S (S= IM/Is, em que IM é a intensidade média incidente no material e Is a intensidade de saturação). A partir desses resultados é possível determinar o parâmetro de conversão ascendente Auger (γ), desde que se conheça a população total do Cr+3 ( N0) e o tempo de vida de emissão τ(τ-1=τR-1+τNR-1) do material investigado. Este método é apresentado para LiSAF dopados com 1% e 7% de Cr+3 , e LiSGaF 4.7% de dopagem de Cr+3, excitados em regime cw sob 15°C. No caso dos polímeros, estudamos a caracterização das propriedades não lineares (eletrônica e térmica) das amostras de polianilina (PANI) dopadas e não-dopadas com H2SO4 na forma plastificada e dissolvida em dimetil sulfóxido (DMSO). Utilizamos para isso as técnicas de LT (cw) e Z-scan (cw e pulso de 70 ps). As medidas foram realizadas em função da concentração de PANI e temperatura. Utilizando um laser de Nd:YAG com um trem de pulsos, realizamos um estudo dinâmico da não linearidade em função da concentração da PANI. Dessa forma pudemos discriminar o efeito eletrônico do efeito térmico, determinando o índice de refração não linear (n2f) um índice térmico (n2cth) que está relacionado ao parâmetro térmico dn/dT (variação do coeficiente óptico com a temperatura). / In this work we studied the effect of nonlinear refraction in Cr+3 doped fluoride host crystals and polymers. The fluoride crystals have been attractive due a broad emission bandwidth and a tunable solid-state lasing in the range of approximately 780-1010 nm. Applying the Thermal Lens (TL) technique, we accomplished a quantitative study of the behavior of the quantum efficiency, in the presence of the processes of the fluorescence thermal quenching and upconversion processes. We introduced a new method of application of the TL technique, which makes possible the determination of the quantum efficiency as a function of the saturation parameter S (S= IM/Is, where IM is the medium intensity in the material and Is, the saturation intensity). Based on those results it is possible to determine the Auger upconversion parameter (γ), it one knows the total population of Cr+3 (N0) and the emission lifetime τ(τ-1=τR-1+τNR-1) of the investigated material. This method is presented for 1% and 7% Cr+3 doped LiSAF, and 4.7% of Cr+3 doped LiSGaF, upon excitation in the cw regime at 15°C. In the case of the polymers, we studied the nonlinear properties (electronics and thermal nonlinearities) of the polyaniline samples (PANI) doped and nondoped with H2SO4 in the film form and dissolved in dimethylsulfoxide. We used the LT (cw) and Z-scan (cw and pulse of 70 ps) techniques. The measurements were accomplished as a function of the concentration of PANI and temperature. Using a laser of Nd:YAG with pulse trains, we accomplished the dynamic behavior of the optical nonlinearity as a function of the PANI concentration. By this method we were able to discriminate between electronic and thermal lensing nonlinearities, and allows the determination of the nonlinear refractive index (n2f) and thermal index (n2cth) that is related to the thermal parameter dn/dT (temperature coefficient of refractive index).

The goal of this project was to develop techniques and instrumentation to measure the elastic properties of the lens and lens capsule in situ and their changes with age using Atomic Force Microscopy (AFM). The studies include the construction, characterization, and calibration of laboratory-based Atomic Force Microscope (AFM) to measure mechanical properties of ophthalmic tissues. Atomic Force Microscopy is a nanoscale imaging technique that has been applied to mechanical property measurement through nanoindentation. Young's modulus of elasticity is determined by monitoring the cantilever deflections when it contacts the sample. The studies also include the development of tissue preparation techniques to enable measurement of the lens elasticity using AFM. This study found that lens capsule elasticity decreases with age, outer lens cortex elasticity remains constant with age, and the inner lens cortex is stiffer than the outer lens cortex. The effect of the changing biometry and mechanical properties with age was investigated by developing a mathematical model of accommodation. These changes will be the limiting factor to accommodative amplitude. Changes in lens capsule mechanical properties will affect the maximal accommodative amplitude in older eyes.

This thesis describes a new type of refractive lens for hardx-rays. It is shown that a linear array of prisms, slightlyinclined with respect to the optical axis, will form a linefocus at a certain distance from the lens. Hence, the namemulti-prism lens. These lenses are free from sphericalaberration and are similar to planar parabolic compoundrefractive lenses in terms of performance. However, theydistinguish themselves in that only planar surfaces need to befabricated. A special feature is that the focal length can beeasily varied by adjusting the inclination angle. Theoretical calculations, based on geometrical and physicaloptics, are used to characterize the lenses. Aberrations arediscussed, as well as the sensitivity to fabricationimperfections, and insufficient flatness is identified as apotential problem. Ray-tracing is used to test theapproximations and assumptions used in the theory. Applicationsin x-ray microscopy and mammography are discussed. Lenses have been made of beryllium, silicon, epoxy anddiamond using different methods. Results from measurements ofsurface roughness and figure error show that the imperfectionsof the silicon and epoxy lenses should have a small impact,while the beryllium lenses should suffer from strongscattering. Experiments were performed at the EuropeanSynchrotron Radiation Facility and sub-µm focal linewidths, close to theoretical expectations, were measured forsilicon and epoxy lenses at 30 keV and 14 keV, respectively.Insertion gains up to 40 were reached. Two crossed lenses wereused to obtain focusing in two dimensions and a point focus.The smallest measured focal spot size was 1.0 µm by 5 .4µm, and an insertion gain exceeding 100 was achieved usingepoxy lenses. The diamond lenses suffered from voids in the materialformed in the chemical vapor deposition process, butnevertheless provided focal lines less than 2 µm in width,albeit at at relatively low insertion gain of 13. Due to theirexcellent thermal properties, these lenses are put forward ascandidates for optics at the next generationultra-high-intensity synchrotron beams and x-ray free electronlasers. Keywords:x-ray, optics, refractive, lens, mammography,synchrotron. / QC 20100524

Transmitarrays have been shown to be viable architectures for achieving high-directivity reconfigurable apertures. The existing work on reconfigurable transmitarrays is sparse, with only a few experimental demonstrations of reconfigurable implementations. Furthermore, of the designs that have been presented, different approaches have been proposed, but the advantages and drawbacks of these approaches have not been compared. Therefore, in this thesis we present a systematic study of the different approaches to designing reconfigurable transmitarrays, and present designs following these approaches with experimental validation. First, we investigate the distributed-scatterer approach, which is modeled with layers of identical scattering surfaces. We characterize the beamforming capabilities and then present a Method of Moments technique for analyzing and optimizing designs that follow this approach. Then, we present experimental results for a unit cell with varactor-loaded dipoles following this approach. From these results, we demonstrate that the structure thickness following this approach is problematic for beamforming applications. Taking the coupled-resonator approach, we next present a slot-coupled patch design that is significantly thinner and easier to fabricate than designs that follow the first approach. Implementing this design in a fully reconfigurable transmitarray, we demonstrate two-dimensional beamforming. An advantage of this design is that it can also operate as a reflectarray. Next, following the guided-wave approach, we present a transmitarray design that uses a bridged-T phase shifter and proximity-coupled differentially-fed stacked patches. Not only does this design not require vias, it is has a large fractional bandwidth of 10 percent, which is unprecedented in reconfigurable transmitarrays. Implementing this design in a full transmitarray, we experimentally demonstrate reconfigurable two-dimensional beamsteering, as well as shaped-beam synthesis. The main contributions of this thesis are two-fold. First, we thoroughly and systematically compare the transmitarray approaches, which has not been previously done in literature. Secondly, we experimentally demonstrate a reconfigurable array design that achieves better bandwidth, scan angle range, and beam-shaping capability, than existing designs, with reduced fabrication complexity and physical profile.

The goal of galaxy classification is to understand the physical basis for the wide range in shapes and structures exhibited by galaxies in the local and high redshift universe. We present a catalog of visually classified galaxies from the Sloan Digital Sky Survey with detailed morphological classifications including bars, rings, lenses, tails, warps, dustlanes, arm flocculence and multiplicity (so called ’fine structure’). This thesis explores the importance of galaxy morphology by probing its relationship to physical properties. Our analysis includes an investigation of correlations between fine structures and AGN activity. This sample defines a comprehensive local galaxy sample which we use to study the low redshift universe both qualitatively and quantitatively. We find the stellar mass appears to be a defining characteristic of a galaxy. The break in most correlations of physical properties with morphology is due to a lack of late type, massive disk galaxies. Our analysis of the size-mass relations of galaxies as a function of morphology (T-Type) has revealed many interesting connections. We find the size-mass relation of Sa, Sab, Sb, and Sbc galaxies bifurcates into two families of objects as one moves down the sequence such that the high concentration branch exhibits a similar slope to low concentration early type (E) galaxies suggesting a closer than expected physical (possibly evolutionary) connection between the two populations. We find bar fraction is bimodal with respect to mass (at 3 x 10^10 M) and color (at g - r ∼ 0.55). The dependence is seen to intimately depend on central concentration such that objects below the transition mass with low concentrations have a higher bar fraction than objects above the transition mass which have high bar fractions for high concentration systems. In addition we find the presence of an AGN alters the behavior and abundance of barred/ringed galaxies in the high mass peak such that the bar/ring fractions increase with mass in nonactive galaxies whereas they decrease with mass in active galaxies. AGN fractions are also decreasing in the same mass range possibly implying a positive correlation between fine structure and ring formation.

Transmitarrays have been shown to be viable architectures for achieving high-directivity reconfigurable apertures. The existing work on reconfigurable transmitarrays is sparse, with only a few experimental demonstrations of reconfigurable implementations. Furthermore, of the designs that have been presented, different approaches have been proposed, but the advantages and drawbacks of these approaches have not been compared. Therefore, in this thesis we present a systematic study of the different approaches to designing reconfigurable transmitarrays, and present designs following these approaches with experimental validation. First, we investigate the distributed-scatterer approach, which is modeled with layers of identical scattering surfaces. We characterize the beamforming capabilities and then present a Method of Moments technique for analyzing and optimizing designs that follow this approach. Then, we present experimental results for a unit cell with varactor-loaded dipoles following this approach. From these results, we demonstrate that the structure thickness following this approach is problematic for beamforming applications. Taking the coupled-resonator approach, we next present a slot-coupled patch design that is significantly thinner and easier to fabricate than designs that follow the first approach. Implementing this design in a fully reconfigurable transmitarray, we demonstrate two-dimensional beamforming. An advantage of this design is that it can also operate as a reflectarray. Next, following the guided-wave approach, we present a transmitarray design that uses a bridged-T phase shifter and proximity-coupled differentially-fed stacked patches. Not only does this design not require vias, it is has a large fractional bandwidth of 10 percent, which is unprecedented in reconfigurable transmitarrays. Implementing this design in a full transmitarray, we experimentally demonstrate reconfigurable two-dimensional beamsteering, as well as shaped-beam synthesis. The main contributions of this thesis are two-fold. First, we thoroughly and systematically compare the transmitarray approaches, which has not been previously done in literature. Secondly, we experimentally demonstrate a reconfigurable array design that achieves better bandwidth, scan angle range, and beam-shaping capability, than existing designs, with reduced fabrication complexity and physical profile.

The goal of galaxy classification is to understand the physical basis for the wide range in shapes and structures exhibited by galaxies in the local and high redshift universe. We present a catalog of visually classified galaxies from the Sloan Digital Sky Survey with detailed morphological classifications including bars, rings, lenses, tails, warps, dustlanes, arm flocculence and multiplicity (so called ’fine structure’). This thesis explores the importance of galaxy morphology by probing its relationship to physical properties. Our analysis includes an investigation of correlations between fine structures and AGN activity. This sample defines a comprehensive local galaxy sample which we use to study the low redshift universe both qualitatively and quantitatively. We find the stellar mass appears to be a defining characteristic of a galaxy. The break in most correlations of physical properties with morphology is due to a lack of late type, massive disk galaxies. Our analysis of the size-mass relations of galaxies as a function of morphology (T-Type) has revealed many interesting connections. We find the size-mass relation of Sa, Sab, Sb, and Sbc galaxies bifurcates into two families of objects as one moves down the sequence such that the high concentration branch exhibits a similar slope to low concentration early type (E) galaxies suggesting a closer than expected physical (possibly evolutionary) connection between the two populations. We find bar fraction is bimodal with respect to mass (at 3 x 10^10 M) and color (at g - r ∼ 0.55). The dependence is seen to intimately depend on central concentration such that objects below the transition mass with low concentrations have a higher bar fraction than objects above the transition mass which have high bar fractions for high concentration systems. In addition we find the presence of an AGN alters the behavior and abundance of barred/ringed galaxies in the high mass peak such that the bar/ring fractions increase with mass in nonactive galaxies whereas they decrease with mass in active galaxies. AGN fractions are also decreasing in the same mass range possibly implying a positive correlation between fine structure and ring formation.