Low_resolution_Thesis_CDD_221009_public - Visual Optics and ...

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

CHAPTER 5 pulses. Fluence, repetition rate, and spot shapes and diameters varied across lasers. The optical zone was set to 6.5 mm in all cases. 5.2.2. Artificial eyes The artificial eyes consisted on plastic cylinders of Filofocon A (Dorronsoro et al., 2008b), with a diameter of 12.7 mm, finished either on a polished flat or spherical (7.8-mm nominal radii of curvature) surface. All eyes had an artificial iris (6.5 mm aperture) located 3.5 mm behind the artificial cornea. The artificial iris is formed by a groove painted on its anterior surface. The nominal eye length was 24.65 mm in all eyes, so that the back focal plane of the spherical surfaces is near the back surface - also polished- of the cylinder. The artificial eyes were manufactured by MedLens, INC, Front Royal, VA, USA. The first surface was re-polished in a precision optics lathe to ensure high surface precision (individually assessed on a profilometer, section 2.4) before the ablations. To define the orientation of the artificial corneas, they were marked at the edge with a 1-mm length meridional line. Figure 5.1(a) shows a photograph of two of the artificial eyes of the study. A total of 40 Filofocon eyes (20 flat and 20 spherical) were ablated under different conditions during the study. The artificial eyes were placed in a support (see Fig. 5.1(b)) that consists of a CMOS chip (from a webcam) acting as an artificial retina, a tip and tilt platform (for both the eye and the CMOS chip), and a tunable filter. The pixel position of the CMOS chip corresponding to the center of the cylinder was previously calibrated and considered as the artificial fovea. The artificial fovea and the artificial pupil define the line of sight of the artificial eye, which can be oriented using the tip and tilt platform. Table 5.1. Laser platforms used in this study. (Nominal data from www.fda.gov) Alcon LADAR Vision Bausch & Lomb Technolas 217Z100 Wavelight Allegretto EyeQ Algorithm Standard Zyoptix Tissue Saving F-CAT Peak Fluence (mJ/cm 2 ) Average Fluence 400 210 120 400 200 Repetition Rate 100 Hz 100 Hz 400 Hz Spot Shape Spot Diameter (mm) Gaussian 0.95 Truncated G. 1 and 2 Gaussian 0.95 Optical Zone 6.5 mm Ablation Zone 8 mm 9.6 mm 8 mm Eye tracker Disabled Wavelength 193 nm 5.2.3. Ablation protocol with clinical lasers The artificial eyes were ablated in the different operating rooms where the clinical lasers were located, and the full experimental procedure supervised by the investigators. The lasers were fine-adjusted and calibrated by each company’s technical support experts before each session. During the ablations, the lasers were operated by the surgeon or the operating room assistants in charge at each clinic. All standard procedures were followed except for the eye tracker that was disabled (and thus the pupil centered manually). The optical zone was set to 6.5 mm. The ablation 140
OPTIMIZED LASER PLATFORMS patterns selected were: Zyoptix Tissue Saving for the Technolas 217 Z100, Standard algorithm for the LADAR-vision and F-CAT for the Allegretto Eye-Q. An additional procedure was needed to align the artificial eye to the laser. Each clinical laser has a different fixation stimulus, typically a collimated laser beam (red line in Fig. 5.1 (b)). The alignment requires the superposition of that stimulus beam with the eye’s line of sight (green line in Fig. 5.1 (b)). In practice, this involves bringing the stimulus (imaged on the CMOS sensor through the artificial eye) to the fovea (reference pixel), by adjusting the tip and tilt platform. To avoid image saturation of the fixation spot, the intensity of the fixation stimuli was adjusted with a tunable filter. The filter was moved aside during ablation. After fixation adjustment, pupil centration was achieved as in patients. The presence of multiple colinear reflexes confirmed the correct centration and alignment of the eye. Pairs of flat and spherical artificial eyes were always ablated consecutively (see Fig. 5.2), under identical conditions (correction, algorithm, calibration state, centration and alignment). Right before each pair (flat/sphere) of myopic corrections, the laser fluence was checked (and calibrated if needed), and the alignment adjusted. Five pairs of clinical ablations (on flat and spherical surfaces) were performed for each laser. Three pairs of refractive surgery procedures were performed with -9 D corrections, one pair with -6 D and one pair with -3 D. As the F-CAT algorithm (Wavelight) has adjustable target asphericity, with this laser we ablated two sets of artificial corneas with two different values of the parameter Q: Q=0 and 0.25. We checked (using a thermosensitive sheet) that the differences in laser vergence from the center to the periphery were negligible. Therefore the ablations on flat surfaces should not be affected by non-normal incidence. a) b) Tunable filter Artificial cornea + iris Fixation “fovea” (CCD) Tip & tilt platform for fixation Fig. 5.1. a) Artificial eyes of Filofocon A (flat and spherical). b) Artificial eye support. The red line represents the fixation stimulus of the laser, while the green line represents the line of sight of the eye. Aligning means to make both axes coincident. 5.2.4. Pre- and Post- operative measurements The PLoptical profilometric microscope described in Section 2.1.1.2 was used to measure the shape of the first surface of the artificial eyes both before and after the 141
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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
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 133: ABLATION PROPERTIES OF FILOFOCON A
Page 137: OPTIMIZED LASER PLATFORMS 5.1 ABSTR
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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Page 187: 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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