This diploma thesis focuses on the definition of cyborgization and to delimit it. The cyborgizatoon of body is one of the ways of human improvement next to gene manipulation and neuromanipulation. It is difficult to express the specific definition because the experts have a different point of view, what for thesis shows various point of view -- both technooptimistic and technopesimistic -- and it tries to find the most suitable definition. People do not want to admit the cyborgization is not only vision of distant future but all of us are the cyborgs practically. What for the thesis deals with various cyborgization methods using in practice or developing to apply them in practice in a short time. The major focus is put to eyesight, the thesis gives a detailed description of refractive surgery, it develops very fast nowadays. The thesis also deals with controversial topic -- digital chips beneath skin -- and then it tries to find an answer to cyborgization is able to separate the society.

Dans un contexte d’augmentation du nombre d’amétropes dans la population mondiale, et en conséquence, de l’accroissement du recours aux techniques de corrections chirurgicales, la compréhension et l’amélioration de celles-ci sont un enjeu crucial. Nous avons cherché à améliorer la prédictibilité de certains résultats postopératoires dans le cas d’un LASIK (Laser-Assisted In-Situ Keratomileusis), d’une PKR (Photorefractive Keratectomy) ou d'une chirurgie de la cataracte, et ainsi formuler des recommandations pratiques qui contribueraient au développement de stratégies de traitement davantage personnalisés. Pour cela, nous avons utilisé prospectivement des méthodologies de « contrôle de qualité » des chirurgies sur de larges échantillons de patients. Dans un premier temps, nous avons étudié la dynamique pupillaire dans le cadre de chirurgies au LASIK et notamment le rôle du centre pupillaire, point de référence important dans les stratégies de centrage. Nous avons également évalué la dynamique du diamètre pupillaire et les modifications du segment antérieur sur des yeux subissant une chirurgie de la cataracte. La seconde partie du travail s’est focalisée sur le rôle de l’épithélium dans la topographique cornéenne. Nous avons comparé les topographies spéculaires de l'épithélium et de la couche de Bowman sur des cornées saines et des cornées kératoconiques, présentant une myopie faible à modérée corrigée par PKR. Enfin, dans la dernière partie de notre recherche, nous nous sommes intéressés aux changements de paramètres anatomiques de l'oeil, des performances visuelles et de la qualité de vision subjective survenant dans un échantillon d’yeux myopes après un LASIK réalisé avec le laser WaveLight® Refractive Suite (Alcon® Laboratories Inc., USA). / While the number of ametropic eyes in the world’s population and consequently the use of surgical correction techniques is increasing, understanding and improving these techniques is a crucial issue. We sought to improve the predictability of certain postoperative results in the case of LASIK (Laser-Assisted In-Situ Keratomileusis), PRK (Photorefractive Keratectomy) and cataract surgery, and thus to formulate practical recommendations that would contribute to the development of more personalized treatment strategies. To achieve this objective, we have prospectively used "quality control" methodologies to assess surgeries performed on large samples of patients. First, we studied the pupillary dynamics in LASIK surgery and in particular the role of the pupillary centre, an important point of reference in the centration strategies. We also assessed the dynamics of pupillary diameter and anterior segment changes on eyes undergoing cataract surgery. The second part of the work focused on the role of the epithelium in the corneal topography. We compared specular topographies of the epithelium and Bowman's layer in healthy and keratoconus corneas with mild to moderate myopia corrected by PRK. Finally, in the last part of our research, we were interested in the changes in anatomical parameters of the eye, visual performance and subjective quality of vision occurring in a sample of myopic eyes after LASIK performed with the WaveLight® Refractive Suite (Alcon® Laboratories Inc., USA).

No description available.

Aberrations affect image quality of the eye away from the line of sight as well as along it. High amounts of lower order aberrations are found in the peripheral visual field and higher order aberrations change away from the centre of the visual field. Peripheral resolution is poorer than that in central vision, but peripheral vision is important for movement and detection tasks (for example driving) which are adversely affected by poor peripheral image quality. Any physiological process or intervention that affects axial image quality will affect peripheral image quality as well. The aim of this study was to investigate the effects of accommodation, myopia, age, and refractive interventions of orthokeratology, laser in situ keratomileusis and intraocular lens implantation on the peripheral aberrations of the eye. This is the first systematic investigation of peripheral aberrations in a variety of subject groups. Peripheral aberrations can be measured either by rotating a measuring instrument relative to the eye or rotating the eye relative to the instrument. I used the latter as it is much easier to do. To rule out effects of eye rotation on peripheral aberrations, I investigated the effects of eye rotation on axial and peripheral cycloplegic refraction using an open field autorefractor. For axial refraction, the subjects fixated at a target straight ahead, while their heads were rotated by ±30º with a compensatory eye rotation to view the target. For peripheral refraction, the subjects rotated their eyes to fixate on targets out to ±34° along the horizontal visual field, followed by measurements in which they rotated their heads such that the eyes stayed in the primary position relative to the head while fixating at the peripheral targets. Oblique viewing did not affect axial or peripheral refraction. Therefore it is not critical, within the range of viewing angles studied, if axial and peripheral refractions are measured with rotation of the eye relative to the instrument or rotation of the instrument relative to the eye. Peripheral aberrations were measured using a commercial Hartmann-Shack aberrometer. A number of hardware and software changes were made. The 1.4 mm range limiting aperture was replaced by a larger aperture (2.5 mm) to ensure all the light from peripheral parts of the pupil reached the instrument detector even when aberrations were high such as those occur in peripheral vision. The power of the super luminescent diode source was increased to improve detection of spots passing through the peripheral pupil. A beam splitter was placed between the subjects and the aberrometer, through which they viewed an array of targets on a wall or projected on a screen in a 6 row x 7 column matrix of points covering a visual field of 42 x 32. In peripheral vision, the pupil of the eye appears elliptical rather than circular; data were analysed off-line using custom software to determine peripheral aberrations. All analyses in the study were conducted for 5.0 mm pupils. Influence of accommodation on peripheral aberrations was investigated in young emmetropic subjects by presenting fixation targets at 25 cm and 3 m (4.0 D and 0.3 D accommodative demands, respectively). Increase in accommodation did not affect the patterns of any aberrations across the field, but there was overall negative shift in spherical aberration across the visual field of 0.10 ± 0.01m. Subsequent studies were conducted with the targets at a 1.2 m distance. Young emmetropes, young myopes and older emmetropes exhibited similar patterns of astigmatism and coma across the visual field. However, the rate of change of coma across the field was higher in young myopes than young emmetropes and was highest in older emmetropes amongst the three groups. Spherical aberration showed an overall decrease in myopes and increase in older emmetropes across the field, as compared to young emmetropes. Orthokeratology, spherical IOL implantation and LASIK altered peripheral higher order aberrations considerably, especially spherical aberration. Spherical IOL implantation resulted in an overall increase in spherical aberration across the field. Orthokeratology and LASIK reversed the direction of change in coma across the field. Orthokeratology corrected peripheral relative hypermetropia through correcting myopia in the central visual field. Theoretical ray tracing demonstrated that changes in aberrations due to orthokeratology and LASIK can be explained by the induced changes in radius of curvature and asphericity of the cornea. This investigation has shown that peripheral aberrations can be measured with reasonable accuracy with eye rotation relative to the instrument. Peripheral aberrations are affected by accommodation, myopia, age, orthokeratology, spherical intraocular lens implantation and laser in situ keratomileusis. These factors affect the magnitudes and patterns of most aberrations considerably (especially coma and spherical aberration) across the studied visual field. The changes in aberrations across the field may influence peripheral detection and motion perception. However, further research is required to investigate how the changes in aberrations influence peripheral detection and motion perception and consequently peripheral vision task performance.

There has been widespread interest in corneal biomechanics over recent years, driven largely by the advancements in, and the popularity of refractive surgery techniques and subsequent concerns over their safety. Lately there has been interest into whether crosslinking, which is currently used for the treatment of keratoconus, could be developed as a minimally invasive technique to change the refractive power of the cornea by selectively changing the corneal biomechanics in specific regions to induce a shape change. Successful application of this technique requires a detailed understanding of corneal biomechanics and so far, little is known about the biomechanics of this complex tissue. The current lack of understanding can be mostly attributed to the absence of a suitable measurement technique capable of examining the dynamic behaviour of the cornea under physiological loading conditions. This thesis describes the development of a novel full-field, ex vivo, measurement method incorporating speckle interferometric techniques, to examine the biomechanics of the cornea before and after crosslinking in response to hydrostatic pressure fluctuations representative of those that occur in vivo during the cardiac cycle. The eventual measurement system used for the experiments detailed in this thesis incorporated; an Electronic Speckle Pattern Interferometer (ESPI), a Lateral Shearing Interferometer (LSI) and a fringe projection shape measurement system. The combination of these systems enabled the 3-dimensional components of surface displacement and the 1st derivative of surface displacement to be determined in response to small pressure fluctuations up to 1 mmHg in magnitude. The use of both ESPI and LSI together also enabled the applicability of LSI for measurement of non-flat surfaces to be assessed, and limitations and error sources to be identified throughout this work. To enable the measurement of corneal biomechanics, part of this thesis was concerned with the design of a bespoke loading rig. A chamber was designed that could accommodate tissue of both porcine and human origin. This chamber was linked to a hydraulic loading rig, whereby the cornea could be held at a baseline pressure representative of normal intraocular pressure and small pressure variations could be introduced by the automated vertical movement of the reservoir supplying the chamber. Experiments were conducted on a range of non-biological samples with both flat and curved surface topography, and both uniform and non-uniform mechanical properties, to determine if the measurement configuration was giving the expected measurement data and the loading rig was stable and repeatable. Following experiments on non-biological samples, a range of experiments were conducted on porcine corneas to develop a suitable testing methodology and address some of the challenges associated with corneal measurement, including transparency and hydration instability. During these investigations, a suitable surface coating was identified to generate an adequate return signal from the corneal surface, while not interfering with the response. Alongside this, the natural variation in the response of the cornea was investigated over the total experimental time, and a range of data was presented on corneas before and after crosslinking, which confirmed the suitability of the measurement methods for the assessment of crosslinking. Ultimately, a small sample size of six human corneas were investigated before and after crosslinking in specific topographic locations. From the experiments on human and porcine corneas, full-field maps of surface deformation have been presented, and a compliant region incorporating the peripheral and limbal areas has been identified as being fundamental to the response of the cornea to small pressure fluctuations. In addition to this, the regional effects of crosslinking in four different topographic locations on corneal biomechanics have been evaluated. From this, it has been demonstrated that crosslinking in specific regions in isolation can influence the way the cornea deforms to physiological-scale fluctuations in hydrostatic pressure and this could have implications for refractive correction.

No description available.

Objetivo: Investigar as alterações biomecânicas da córnea de suínos induzidas pela confecção de lamelas pediculadas de diferentes espessuras pelo laser de femtossegundo. Métodos: Para a formação dos dois grupos, 12 olhos de porcos foram usados: lamelas pediculadas de 100 e de 300 micrômetros confeccionadas pelo laser de femtossegundo. Cada olho foi submetido aos seguintes exames, antes da criação das lamelas: topografia por rasterstereography, Ocular Response Analyzer (ORA), tomografia do segmento anterior por coerência óptica para a avaliação paquimétrica corneal e das lamelas criadas e sistema de velocidade de onda (SVO), que mede a velocidade de propagação de ondas acústicas entre dois transdutores posicionados na superfície corneal antes e imediatamente, após a feitura da lamela. O primerio passo foi desenhado para o estudo das diferenças em relação à histerese corneal, fator de resistência corneal, mudanças na curvatura e velocidade de propagação de onda acústica entre córneas com lamelas finas e espessas. Posteriormente, as lamelas foram amputadas, e as medidas do sistema de velocidade de onda foram repetidas. Resultados: A média de espessura das lamelas ± desviopadrão (DP) foi de 108,5±6,9 (8,5% da espessura total) e 307,8±11,5 m (22,9% da espessura total), para os grupos de lamelas finas e espessas, respectivamente (p< 0,001). Histerese corneal e o fator de resistência corneal não apresentaram diferença estatística, após a criação de lamelas finas (p = 0,81 e p = 0,62, respectivamente). Histerese corneal foi significantemente mais baixa, depois da confecção de lamelas mais espessas (8,0±1,0 para 5,1±1,5 mmHg para medidas pré e pós-operatórias, respectivamente, p = 0,003, diminuição de 36,25%) e fator de resistência corneal também mostrou significante diminuição nesse grupo, após o procedimento cirúrgico; valores médios pré e pós-operatórios de 8,2±1,6 e 4,1±2,5 mmHg respectivamente (p= 0,007), diminuição de 50%. A ceratometria média simulada apresentou maiores valores, após a confecção das lamelas mais espessas em relação ao pré-operatório (ceratometria pré e pós-operatória de 39,5±1 D e 45,9±1,2 D, respectivamente, p= 0,003). Para o grupo de lamelas finas, não houve diferença estatisticamente significante (ceratometria pré e pós-operatória de 40,6±0,6 D e 41,4±1,0 D, respectivamente, p=0,55). Em relação ao Sistema de Velocidade de Onda, após a criação das lamelas e sua amputação, houve diminuição da velocidade de propagação acústica, embora na maior parte das posições não fosse estatisticamente significante. Conclusão: Nas condições experimentais estabelecidas por este estudo, a criação de lamelas de maior espessura pareceu exercer efeito mais relevante sobre a biomecânica da córnea de suínos / Purpose: To study the impact of programmed flaps at two different thicknesses on the biomechanical properties of the swine corneas. Methods: Twelve pig eyes were enrolled in this study and were formed two groups: 100m and 300 m flaps performed with the femtosecond laser. Each eye had the following procedure before the flap creation: raster photograph topographic maps, Ocular Response Analyzer (ORA), Optical Coherence Tomography to measure the pachymetry and flap thickness and Surface Wave Velocity system which is a prototype system that measures sonic wave propagation time between two transducers positioned on the corneal surface before and after flap creation. This first step was designed to investigate the differences in respect to corneal hysteresis, corneal resistance factor, curvature change and ultrasonic wave propagation between the groups with thinner and thicker flaps. After this initial procedure, flap amputation was performed and new measurements with the surface wave velocity system were taken again. Results: Measured flap thicknesses averaged 108.5±6.9 (8.5% of the total cornea) and 307.8±11.5 m (22.9% of the total cornea) for thin and thick flap groups, respectively (p< 0.001). Hysteresis and corneal resistance factor did not change significantly after flap creation in the thin flap group (p = 0.81 and p = 0.62, respectively). With thicker flaps, both parameters decreased significantly from 8.0±1.0 to 5.1±1.5 mmHg (p=0.003, reduction of 36.25%) and from 8.2±1.6 to 4.1±2.5 mmHg, respectively (p = 0.007), reduction of 50%. Simulated keratometry values increased in the thick flap group (from 39.5±1 D to 45.9±1.2 D, p=0.003) after flap creation and not in the thin flap group (from 40.6±0.6D to 41.4±1.0D, p= 0.55). Regarding surface wave velocity analysis, the surgical procedures induced lower values in some positions although most of them did not present statistically different results. Conclusion: In this experimental model, thicker flaps seemed to have a greater effect on the biomechanics of the swinish cornea

Objetivo: Investigar as alterações biomecânicas da córnea de suínos induzidas pela confecção de lamelas pediculadas de diferentes espessuras pelo laser de femtossegundo. Métodos: Para a formação dos dois grupos, 12 olhos de porcos foram usados: lamelas pediculadas de 100 e de 300 micrômetros confeccionadas pelo laser de femtossegundo. Cada olho foi submetido aos seguintes exames, antes da criação das lamelas: topografia por rasterstereography, Ocular Response Analyzer (ORA), tomografia do segmento anterior por coerência óptica para a avaliação paquimétrica corneal e das lamelas criadas e sistema de velocidade de onda (SVO), que mede a velocidade de propagação de ondas acústicas entre dois transdutores posicionados na superfície corneal antes e imediatamente, após a feitura da lamela. O primerio passo foi desenhado para o estudo das diferenças em relação à histerese corneal, fator de resistência corneal, mudanças na curvatura e velocidade de propagação de onda acústica entre córneas com lamelas finas e espessas. Posteriormente, as lamelas foram amputadas, e as medidas do sistema de velocidade de onda foram repetidas. Resultados: A média de espessura das lamelas ± desviopadrão (DP) foi de 108,5±6,9 (8,5% da espessura total) e 307,8±11,5 m (22,9% da espessura total), para os grupos de lamelas finas e espessas, respectivamente (p< 0,001). Histerese corneal e o fator de resistência corneal não apresentaram diferença estatística, após a criação de lamelas finas (p = 0,81 e p = 0,62, respectivamente). Histerese corneal foi significantemente mais baixa, depois da confecção de lamelas mais espessas (8,0±1,0 para 5,1±1,5 mmHg para medidas pré e pós-operatórias, respectivamente, p = 0,003, diminuição de 36,25%) e fator de resistência corneal também mostrou significante diminuição nesse grupo, após o procedimento cirúrgico; valores médios pré e pós-operatórios de 8,2±1,6 e 4,1±2,5 mmHg respectivamente (p= 0,007), diminuição de 50%. A ceratometria média simulada apresentou maiores valores, após a confecção das lamelas mais espessas em relação ao pré-operatório (ceratometria pré e pós-operatória de 39,5±1 D e 45,9±1,2 D, respectivamente, p= 0,003). Para o grupo de lamelas finas, não houve diferença estatisticamente significante (ceratometria pré e pós-operatória de 40,6±0,6 D e 41,4±1,0 D, respectivamente, p=0,55). Em relação ao Sistema de Velocidade de Onda, após a criação das lamelas e sua amputação, houve diminuição da velocidade de propagação acústica, embora na maior parte das posições não fosse estatisticamente significante. Conclusão: Nas condições experimentais estabelecidas por este estudo, a criação de lamelas de maior espessura pareceu exercer efeito mais relevante sobre a biomecânica da córnea de suínos / Purpose: To study the impact of programmed flaps at two different thicknesses on the biomechanical properties of the swine corneas. Methods: Twelve pig eyes were enrolled in this study and were formed two groups: 100m and 300 m flaps performed with the femtosecond laser. Each eye had the following procedure before the flap creation: raster photograph topographic maps, Ocular Response Analyzer (ORA), Optical Coherence Tomography to measure the pachymetry and flap thickness and Surface Wave Velocity system which is a prototype system that measures sonic wave propagation time between two transducers positioned on the corneal surface before and after flap creation. This first step was designed to investigate the differences in respect to corneal hysteresis, corneal resistance factor, curvature change and ultrasonic wave propagation between the groups with thinner and thicker flaps. After this initial procedure, flap amputation was performed and new measurements with the surface wave velocity system were taken again. Results: Measured flap thicknesses averaged 108.5±6.9 (8.5% of the total cornea) and 307.8±11.5 m (22.9% of the total cornea) for thin and thick flap groups, respectively (p< 0.001). Hysteresis and corneal resistance factor did not change significantly after flap creation in the thin flap group (p = 0.81 and p = 0.62, respectively). With thicker flaps, both parameters decreased significantly from 8.0±1.0 to 5.1±1.5 mmHg (p=0.003, reduction of 36.25%) and from 8.2±1.6 to 4.1±2.5 mmHg, respectively (p = 0.007), reduction of 50%. Simulated keratometry values increased in the thick flap group (from 39.5±1 D to 45.9±1.2 D, p=0.003) after flap creation and not in the thin flap group (from 40.6±0.6D to 41.4±1.0D, p= 0.55). Regarding surface wave velocity analysis, the surgical procedures induced lower values in some positions although most of them did not present statistically different results. Conclusion: In this experimental model, thicker flaps seemed to have a greater effect on the biomechanics of the swinish cornea