Low_resolution_Thesis_CDD_221009_public - Visual Optics and ...

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

CHAPTER 2 The system control software operates and synchronizes the different elements (scanner, shutter and cameras) for the measurement, assisting in some other operations such as aligning the pupil and the optical system, with a user’s friendly interface. All the useful data such as measurement (dates and times, sampling pattern, pupil size, etc) calibration parameters, or measurement condition (with or without contact lens, for example) are saved in a structured way using excel files that can be used as reports for the measurements (See Fig. 2. 25). All the actions performed (by the operator or by the different components of the software), and the result (successful or not, files involved) are recorded in a log file. This log file can be used as a backup laboratory book to retrospectively track all the measurement session, to improve the data analysis. Fig. 2. 23 shows a snapshot of the control program. The form “Acquisition and Control” allows to set the measurement parameters as well as to start the measurement itself. The sampling pattern (scanned pupil diameter, sampling arrangement and density) can be easily changed. This feature has been very useful for measuring contact lenses, with annular designs. The forms “Pupil Image” and “Retinal Image” allow the visualization of the images corresponding to each camera in real time. This feature is not only useful for the measurements themselves, but also for calibration and alignment purposes. The software also includes a routine, “Test LRT” that allows to verify the correct alignment of the laser beam as well as the correct delivery of the programmed pattern on the pupil. When “Test LRT” is clicked, a series of circumferences indicating the nominal position of the samples and a centration cross appear superimposed to the pupil image (see Image pupil frame in Fig. 2. 23. Simultaneously the shutter opens and the scanner starts to scan the programmed sampling pattern. If we place a screen on the pupil plane, the scanning spot will be visible with the circles superimposed. A thicker circumference indicates the nominal position for the corresponding sample, so that for a correct sampling, the laser spot should lay in the centre of that circle. If we stop the scanner and select the central position for the beam, we can verify that the spot is overlapped with the centration cross. 2.3.2.5. Processing Software for retinal images (ocular aberrations) The software to estimate the ocular aberrations from the set of aerial images was profoundly improved from its original LRT1 version in order to make the computation of aberrations easier, quicker, more robust and efficient, with better quality and traceability of errors or detection of problems, and adapted to the new set-up parameters and possibilities. The contribution of the author of this thesis in this software, in collaboration with Lourdes Llorente, includes: the design of the new data structure; support in the writing of the new Matlab code; support in testing and debugging of the software; Visual Basic interface. Some specific improvements in the software include: 1) Calculation of the processing parameters based on the conditions of the experiment and included in the corresponding calibration data file; 2) Adaptation to the new data structure defined by the control software: input data were read from the files created during the measurements, and structured result files were created for the output data; 3) Organization of the program as a modular structure to allow for a Visual Basic interface, more efficient for the processing and more user-friendly; 86
METHODS 4) New image processing tools: possibility of choosing different processing parameters (thresholds, Zernike order to fit), as well as using default values; manual selection of the Region of Interest or of the images to exclude from the processing when necessary; possibility of undoing the last change; on-line visualization of parameters significant for the processing such as maximum intensity of the images or spot diagram (joint plot of the centroids of the images already processed). 5) A graphic as well as numeric presentation of the results that allows easy detection of series that do not follow the common trend or do not have the same measurement conditions as the rest of the series of the same session. The results file also includes a worksheet were corneal aberrations are saved when available, in order to summarize all the related results in one file. Fig. 2. 26. Snapshot of the processing software interface showing some images before (top row) and after (botton row) processing. A snapshot of the processing software interface is shown in Fig. 2. 26. Basically, raw images are processed (background subtraction, filters and masks application, thresholds setting, etc) in order to isolate each aerial image and locate the corresponding centroid (Fig. 2. 27). Then, the relative distance of each centroid to that of the central ray is calculated (transverse aberration), and the wave aberration is then estimated by fitting the transverse aberration corresponding to each sampled point to the derivatives of the Zernike polynomials, using a least squares method (Cubalchini, 1979). The interface (Fig. 2. 26) allows the user to visualize the raw images, select the next processing to apply to the image and check the image appearance after processing has been applied, with the corresponding centroid position superimposed on the image. As previously mentioned, a joint plot with all the centroids positions (spot diagram) is also available. The program extracts the input data necessary for the wave 87
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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
Page 35 and 36: INTRODUCTION 1.4.6.3. Internal Aber
Page 37 and 38: INTRODUCTION 1.5.2.3. Alternating v
Page 39 and 40: INTRODUCTION and further-more, at l
Page 41 and 42: INTRODUCTION alcohol is used to loo
Page 43 and 44: INTRODUCTION changes in reflectivit
Page 45 and 46: INTRODUCTION Marcos et al. (Marcos
Page 47 and 48: INTRODUCTION 1.7.3. Ablation effici
Page 49 and 50: INTRODUCTION corneal surface may be
Page 51 and 52: INTRODUCTION Algorithm design: The
Page 53 and 54: INTRODUCTION contact lenses the fie
Page 55 and 56: INTRODUCTION 1.10.1. Tear studies A
Page 57 and 58: INTRODUCTION there are still many u
Page 59 and 60: INTRODUCTION 6. Evaluation and unde
Page 61 and 62: METHODS 2Chapter Chapter 2 - Method
Page 63 and 64: METHODS 2.1. MEASUREMENT OF OPTICAL
Page 65 and 66: METHODS In both profilometers, cust
Page 67 and 68: METHODS The measurement method that
Page 69 and 70: METHODS Fig. 2. 9. Set of points in
Page 71 and 72: METHODS Slit lamp Scheimpflug Camer
Page 73 and 74: METHODS representing the deviation
Page 75 and 76: 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: METHODS Fig. 2. 24. Example frame f
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
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OPTIMIZED LASER PLATFORMS 5.1 ABSTR
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CHAPTER 5 pulses. Fluence, repetiti
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CHAPTER 5 ablations. The slit-confo
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CHAPTER 5 (Anera et al., 2003): d S
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CHAPTER 5 asymmetries also appeared
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CHAPTER 5 5.3.4. Ablation patterns
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CHAPTER 5 a) b) : 6.5 mm c) Fig. 5.
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CHAPTER 5 achieve proper reflection
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CHAPTER 5 Both the ablation algorit
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HYBRID PORCINE/PLASTIC MODEL 6.1. A
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CHAPTER 6 6.3.1. Hybrid porcine-pla
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CHAPTER 6 is detected. Therefore, i
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CHAPTER 6 no preferential orientati
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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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