Low_resolution_Thesis_CDD_221009_public - Visual Optics and ...

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CHAPTER 5 asymmetries also appeared on different experimental sessions. Remarkably, the shape of the ablation profile and maximum ablation depth (on Filofocon A) differ substantially across laser platforms, for the same programmed refraction correction and optical zone. 5.3.3. Ablation efficiency factors on plastic Figure 5.4 compares the ablation patterns for two of the lasers: Alcon (left side) and Bausch & Lomb (right side). Unlike Fig. 5.3 (b) where profile cross-sections of ablations on flat surfaces were plotted, Fig. 5.4 shows all the measured points in a radial plot, both for flat and spherical ablated surfaces (for -9 D corrections on Filofocon A). The figure illustrates the large differences in ablation patterns between the two laser platforms. Both the ablation depth and the radial extension of the ablated zone are different. These two lasers are also different in terms of efficiency losses. The high fluence laser (Alcon, left side of Fig. 5.4) is practically free from efficiency losses. The ablation pattern from flat and spherical surfaces are almost identical for this laser, as the measured point to point difference in depth between ablation in flat and spherical surfaces (less than 2 microns) is of the order of the measurement accuracy. Theoretical calculations using the formulation of Anera et al. (Anera et al., 2003) for the particular geometry of the artifical eyes and the ablation properties of this material (Dorronsoro et al., 2008b), predict a maximum difference of 1.1 microns. Sphere Flat Alcon Bausch & Lomb Fig. 5.4. Ablation patterns for two of the lasers: Alcon (left side) and Bausch & Lomb (right side). All the measured points are shown in radial plots, both for flat and spherical ablated surfaces (for -9D corrections on Filofocon A). On the other hand, efficiency effects are clearly noticeable in the low fluence laser (Bausch & Lomb, right side of Fig. 5.4), as the ablation depth is lower on spherical than on flat surfaces. The difference between the ablation pattern on flat and on spherical surfaces is zero at the apex and also outside the ablation zone. There are systematic point to point differences, as high as 6.8 microns in the intermediate points (the theoretical prediction was 6.3 microns). Figure 5.5 shows the measured ablation efficiency factor on Filofocon A (K, calculated from Eq. 5.1) as 2-D maps and radial plots, for the Alcon (Fig. 5.5 (a and b)) and Bausch & Lomb (Fig. 5.5 (c and d)) lasers. The square pattern observed in Figure 5.5 (a) is a trace of the profilometer trajectory. The red line in the 1-D plots 146
OPTIMIZED LASER PLATFORMS (Fig. 5.5 (b and c)) represents the theoretical ablation efficiency factor (K, from Eq. 5.2) for the corresponding laser fluences (400 mJ/cm 2 and 120 mJ/cm 2 for the Alcon and Bausch and Lomb lasers, respectively), and using the ablation properties for Filofocon A that we have reported in a recent study (Dorronsoro et al., 2008b). The experimental ablation efficiency factor at each radial distance from the apex (black squares) is obtained as an angular average of all the measured points (in gray). While the efficiency factor is practically 1 at all points for the high fluence laser (Alcon), it decreases significantly from the center to the periphery in the low fluence laser (Bausch & Lomb). For this laser (and Filofocon A) the effectiveness of ablation in the periphery of the optical zone is only 60%. The theoretical model captures the main experimental trends. The reported ablation efficiency factors were obtained from –9 D ablation patterns. We performed the same analysis on flat/spherical ablated surfaces with –3 D and –6 D corrections, and obtained similar results, although noise had a higher impact on the measured ablation depths. 2D-maps Radial Profiles a) b) : 6.5 mm Alcon c) d) : 6.5 mm Bausch & Lomb Fig. 5.5. Measured ablation efficiency factor in Filofocon A for the Alcon ((a) and (b)) and for the Bausch & Lomb laser ((c) and (d)). (a) and (c) show the efficiency effects at each point. (b) and (d) are radial profiles of all the measured points (gray). The black squares are the angular averages at each radial position. The red line represents the theoretical ablation efficiency factor for the corresponding laser fluences (400 mJ/cm 2 and 120 mJ/cm 2 for the Alcon and Bausch and Lomb lasers, respectively). 147
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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
Page 99: REFRACTIVE SURGERY PMMA MODEL 3.1.
Page 102 and 103: CHAPTER 3 optimization of refractiv
Page 104 and 105: CHAPTER 3 These data demonstrate th
Page 106 and 107: CHAPTER 3 regression line, since it
Page 108 and 109: CHAPTER 3 Figure 3.3 shows one of t
Page 110 and 111: CHAPTER 3 Ablation efficiency facto
Page 112 and 113: CHAPTER 3 considering the same set
Page 114 and 115: CHAPTER 3 3.5.3 Impact of correctio
Page 117: ABLATION PROPERTIES OF FILOFOCON A
Page 121 and 122: ABLATION PROPERTIES OF FILOFOCON A
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 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 162 and 163: CHAPTER 6 is detected. Therefore, i
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
Page 191 and 192: SOFT CONTACT LENS FITTING USING MOD
Page 194: ON-EYE OPTICAL PERFORMANCE OF RIGID
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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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