Low_resolution_Thesis_CDD_221009_public - Visual Optics and ...

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$XXX Congress of the European Society of Cataract and Refractive ...$

CHAPTER 6 is detected. Therefore, in this case we used the Pentacam fitting routines. We studied the agreement between the radii of curvature and asphericity obtained by our fitting procedure and those obtained by Pentacam’s software (see below). 6.4. RESULTS 6.4.1. Validation of the ANTERIOR surface Table 6.1 shows the nominal and measured radii of curvature of glass spherical models. Anterior radii of curvature were estimated within an accuracy of 0.04 mm with respect to the nominal values of the reference spheres, being typically slightly underestimated. Asphericity was -0.02 0.22 on average, close to the expected value (zero) for a sphere, although the variability was high. Astigmatism was higher than expected (power 0.32 0.27, on average), but with random angle, indicating that there are not predominant orientations, and that the average surface is a sphere, as expected. The repeated measurements on the 7.93 mm plastic surface provided similar results (although the cylindrical geometry of the piston produced unwanted reflections that prevented from systematic measurements in all samples). Table 6.1. Validation of Pentacam measurements for ANTERIOR radius. Table 6.2. Validation of Pentacam measurements for POSTERIOR radius. 162
HYBRID PORCINE/PLASTIC MODEL 6.4.2. Validation of the POSTERIOR surface Table 6.2 shows the nominal and estimated posterior radii of curvature in the hybrid porcine/plastic eye model. Each data is the average of the different eyes with similar posterior plastic cornea. There is a good correlation between nominal and estimated radius, although there is higher bias (underestimation) than for the anterior cornea (150 to 400 μm). Despite the low accuracy (the absolute values are not recovered exactly), the repeatability is good (below 100 m), considering that these are individual measurements (non-averaged) of hybrid eyes whose anterior surface varies across measurements. 6.4.3. Correlation between anterior and posterior surfaces 6.4.3.1. Radius Correlations between anterior and posterior corneal surface were performed to assess that the optical distortion correction was successfully applied. Statistically significant correlations between the posterior (fixed) corneal surface and the anterior (variable, as dependent from the specimen and pressure exerted by the piston) would be indicative of artifacts in the correction. This is particularly critical in the current study, when the same eyes are evaluated before and after a change in the anterior cornea. Figure 6.4 shows the anterior radius vs. the deviations in posterior radius for all the posterior corneal samples and all the porcine corneas. Our hybrid porcine/plastic model corneas showed a wide range of anterior radii (from 8.0 to 9.6 mm) for the different combinations of anterior porcine corneas and posterior plastic surfaces. A z- test showed no correlation between anterior radius vs. deviations in posterior radius (p>0.26) for all measurements (averaged across identical conditions). Additional z- tests between anterior and posterior corneal radius for each plastic back surface also showed no correlation (p>0.6). These results indicate that the radius of the anterior surface does not affect the radius measured of the posterior surface. Fig. 6.4. Measurements of Radii 6.4.3.2. Astigmatism Also, the anterior corneas typically showed significant amount of astigmatism (1.9 ± 1.0 D) with preferential orientations in the vertical and horizontal directions, while the estimated astigmatism for the posterior surface was much lower (0.31 ± 0.15 D), with 163
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Doctoral thesis Corneal Ablation an
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Contents Corneal Ablation and Conta
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2.2.1. Fitting surfaces............
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5.3.3. Ablation efficiency factors
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10.5. DISCUSSION...................
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We thank José Antonio Sánchez-Gil
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BOZR Back Optic Zone Radius BCVA Be
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INTRODUCTION 1.1. MOTIVATION The fr
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INTRODUCTION 1.2. THE OPTICAL SYSTE
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INTRODUCTION Myopia is a very commo
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INTRODUCTION a point focus: the dif
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INTRODUCTION system, and tilt repre
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INTRODUCTION term Z 0 2 stands for
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INTRODUCTION which image was shadow
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INTRODUCTION The defocus Zernike te
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INTRODUCTION 1.4.6.3. Internal Aber
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INTRODUCTION 1.5.2.3. Alternating v
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INTRODUCTION and further-more, at l
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INTRODUCTION alcohol is used to loo
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INTRODUCTION changes in reflectivit
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INTRODUCTION Marcos et al. (Marcos
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INTRODUCTION 1.7.3. Ablation effici
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INTRODUCTION corneal surface may be
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INTRODUCTION Algorithm design: The
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INTRODUCTION contact lenses the fie
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INTRODUCTION 1.10.1. Tear studies A
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INTRODUCTION there are still many u
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INTRODUCTION 6. Evaluation and unde
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METHODS 2Chapter Chapter 2 - Method
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METHODS 2.1. MEASUREMENT OF OPTICAL
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METHODS In both profilometers, cust
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METHODS The measurement method that
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METHODS Fig. 2. 9. Set of points in
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METHODS Slit lamp Scheimpflug Camer
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METHODS representing the deviation
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METHODS 2.2.2.2. Ablation pattern f
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METHODS direction. These calculatio
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METHODS eye through the whole pupil
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METHODS (1993) power thresholds for
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METHODS alignment (frontal-illumina
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METHODS Fig. 2. 24. Example frame f
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METHODS 4) New image processing too
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METHODS Fig. 2. 28. Corrected entra
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METHODS Badal lens, corresponds to
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METHODS Each VA measurement consist
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REFRACTIVE SURGERY PMMA MODEL 3.1.
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CHAPTER 3 optimization of refractiv
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CHAPTER 3 These data demonstrate th
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CHAPTER 3 regression line, since it
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CHAPTER 3 Figure 3.3 shows one of t
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CHAPTER 3 Ablation efficiency facto
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Page 114 and 115: CHAPTER 3 3.5.3 Impact of correctio
Page 117: ABLATION PROPERTIES OF FILOFOCON A
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Page 133: ABLATION PROPERTIES OF FILOFOCON A
Page 137: OPTIMIZED LASER PLATFORMS 5.1 ABSTR
Page 140 and 141: CHAPTER 5 pulses. Fluence, repetiti
Page 142 and 143: CHAPTER 5 ablations. The slit-confo
Page 144 and 145: CHAPTER 5 (Anera et al., 2003): d S
Page 146 and 147: CHAPTER 5 asymmetries also appeared
Page 148 and 149: CHAPTER 5 5.3.4. Ablation patterns
Page 150 and 151: CHAPTER 5 a) b) : 6.5 mm c) Fig. 5.
Page 152 and 153: CHAPTER 5 achieve proper reflection
Page 154 and 155: CHAPTER 5 Both the ablation algorit
Page 157: HYBRID PORCINE/PLASTIC MODEL 6.1. A
Page 160 and 161: CHAPTER 6 6.3.1. Hybrid porcine-pla
Page 164 and 165: CHAPTER 6 no preferential orientati
Page 167: ANTERIOR AND POSTERIOR CORNEAL ELEV
Page 171 and 172: ANTERIOR AND POSTERIOR CORNEAL ELEV
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Page 187: SOFT CONTACT LENS FITTING USING MOD
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Page 194: ON-EYE OPTICAL PERFORMANCE OF RIGID
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SOFT MONOFOCAL AND MULTIFOCAL CONTA
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SOFT MONOFOCAL AND MULTIFOCAL CONTA
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CORRELATION BETWEEN RADIUS AND ASPH
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CONCLUSIONS Conclusions This thesis
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CONCLUSIONS 5We have developed a pr
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CONCLUSIONS LIST OF METHODOLOGICAL
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CONCLUSIONS FUTURE RESEARCH LINES T
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CONCLUSIONS LIST OF PUBLICATIONS AN
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REFERENCES References AIZAWA, D., S
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REFERENCES PHOTODECOMPOSITION (APD)
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REFERENCES DORRONSORO, C., CANO, D.
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REFERENCES GISPETS, J., ARJONA, M.
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REFERENCES KOPF, M., YI, F., ISKAND
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REFERENCES MARCOS, S., DORRONSORO,
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REFERENCES NOVO, A., PAVLOPOULOS, G
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REFERENCES SAKIMOTO, T., ROSENBLATT
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REFERENCES WANG, L., DAI, E., KOCH,
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RESÚMENES pacientes reales fue com
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RESÚMENES experimentales de cirug
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RESÚMENES cada punto de las cornea
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RESÚMENES plástico medidas anteri
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RESÚMENES 8 Evaluación óptica de
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RESÚMENES 9 Prestaciones ópticas
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RESÚMENES 10 Calidad óptica y cal
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RESÚMENES A Correlación entre rad
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CONCLUSIONES clínicos. La descripc
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CONCLUSIONES 12 Las superficies ocu
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CONCLUSIONES IMPLICACIONES DE ESTA
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CONCLUSIONES contribuyen a la compr
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(y muchísimo más difícil). Me da
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