Low_resolution_Thesis_CDD_221009_public - Visual Optics and ...

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

CHAPTER 4 For PMMA, more than 70 pulses are required to reach 2% of the corresponding values at 100 pulses (F th = 66.79 mJ/cm 2 and eff = 52000 cm -1 ). 300 (a) Ablation Threshold Fth (mJ/cm 2 ) 250 200 150 FILOFOCON PMMA FILOFOCON PMMA 100 50 0 20 40 60 80 100 # of pulses 60000 (b) Effective absorption coefficient 50000 eff (cm -1 ) 40000 30000 20000 10000 0 0 20 40 60 80 100 # of pulses Fig. 4.5. Ablation properties vs number of pulses for Filofocon A and PMMA: a) Ablation threshold and b) Effective absorption coefficient. Large open symbols -solid line- come from the data of Fig. 4.4. Small solid symbols (dashed line) derived from a second analysis of Fig. 4.2(a). See text for details. 4.4.5 Microscopic structure of the ablation craters Visual inspection of the ablated samples shows that they are transparent up to 240 mJ/cm 2 . At this and higher fluences a progressive darkening with the number of pulses appears in Filofocon A, but not in PMMA. High magnification (100x) reflection images confirms this darkening inside the ablation, revealing different structures in the ablated areas for Filofocon A and PMMA. These images also show a border around the ablated areas which is darker and broader in PMMA. Figure 4.6 shows high 128
ABLATION PROPERTIES OF FILOFOCON A magnification optical images of unablated (left side of the image) and ablated (right) areas in Filofocon A (Fig. 4.6(a)) and PMMA (Fig. 4.6(b)), for 30 pulses and a fluence of 400 mJ/cm 2 . The different structures inside the ablated area (right part of each image) are also present even with very low number of pulses. (a) Filofocon A (b) PMMA Fig. 4.6. High magnification (100x) optical micrographs of Filofocon A (a) and PMMA (b). In both pictures, the ablated zone (400 mJ/cm 2 , 30 pulses) is on the right. The scale bar is 10 m. AFM images (shown in Fig. 4.7) confirm that these structures, close to the resolution limit of the camera of the optical microscope, are real physical structures and not optical effects such as aliasing. (a) Filofocon A (b) PMMA Fig. 4.7. AFM images of the ablated zone (400mJ/cm 2 , 30 pulses) in Filofocon A (a) and PMMA (b). The scalebar is 2 m. The peak to peak depth (color scale range) is 300 nm. 4.5. DISCUSSION We have studied the excimer laser ablation of Filofocon A and PMMA materials, in the operational range of refractive surgery. These materials have been used in previous studies in experimental models of corneal refractive surgery (Dorronsoro et al., 2006a, Chernyak and Campbell, 2003, Dorronsoro et al., 2008a), although their ablation properties were not well established. Both materials show a large range of linear dependence between ablation depth and number of pulses, for different fluences (see Fig. 4.2) as well as between ablation rate (depth/pulse) and the logarithm of the fluence (Beer Lambert law, see Fig. 4.4). We have measured optical and ablation properties of these materials at 193 nm (including index of refraction and extinction coefficient, ablation threshold and effective absorption coefficient) and investigated the structural changes in the material following ablation. We have shown that incubation is not negligible for low fluences, and that the ablation parameters change with the number of pulses, more so in PMMA 129
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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
Page 77 and 78: METHODS direction. These calculatio
Page 79 and 80: METHODS eye through the whole pupil
Page 81 and 82: METHODS (1993) power thresholds for
Page 83 and 84: METHODS alignment (frontal-illumina
Page 85 and 86: METHODS Fig. 2. 24. Example frame f
Page 87 and 88: METHODS 4) New image processing too
Page 89 and 90: METHODS Fig. 2. 28. Corrected entra
Page 91 and 92: METHODS Badal lens, corresponds to
Page 93: 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 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 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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ANTERIOR AND POSTERIOR CORNEAL ELEV
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ANTERIOR AND POSTERIOR CORNEAL ELEV
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SOFT CONTACT LENS FITTING USING MOD
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SOFT CONTACT LENS FITTING USING MOD
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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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