Low_resolution_Thesis_CDD_221009_public - Visual Optics and ...

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

ON-EYE OPTICAL PERFORMANCE OF RIGID GAS PERMEABLE CONTACT LENSES coefficients are also largely reduced, with the exception of spherical aberration (Z 4 0 ): astigmatism, terms 3 (Z 2 2 ) and 5 (Z 2 -2 ) and comatic term 8 (Z 2 -1 ) in Fig. 9.3(b). There is a good correspondence between total and anterior surface aberrations (Figs. 9.3(a) and 9.3(b)). S3 shows an aberration pattern dominated by astigmatism (almost as high as S1), practically all corneal in origin, as indicated by the great correspondence of total and corneal aberrations (Figs. 9.3(c) and 9.3(d)). Spherical aberration is the predominant high order aberration of the cornea, but not of the whole eye. In this subject we found only a small correction of aberrations by the RGP CL. Figure 9.4 summarizes the effect of RGP CLs on total aberrations (RMS) for different orders of the Zernike polynomial expansion, for all subjects. Figure 9.4(a) shows RMS for all terms, excluding tilt and defocus. The CL significantly corrects part of the ocular aberrations in three of our four subjects. RMS decrements range from 0.9 m in S1 to 0.2 m in S3. For subject S4 there is a slight increase in RMS (0.09 m). This value is of the order of the RMS variability (0.11 m for this subject), and therefore it is not statistically significant. This subject has a low amount of aberrations, and internal optics RMS (0.37 m) is comparable to corneal RMS (0.51 m). Anterior surface aberrations decrease however (RMS 0.51 to 0.46), with CL wear. Fig. 9.4. Effect of RGP CLs on total RMS for all subjects. (a): RMS for all terms, excluding tilt and defocus; (b) RMS for 3 rd and higher order.terms (c): RMS for 3 rd order terms; (d) RMS for 5 th and higher order terms. Figure 9.4 (b) shows RMS for all terms of 3 rd and higher order. These terms account for all aberrations that cannot be corrected with conventional ophthalmic lenses. Figure 9.4(c) shows RMS for Zernike coefficients of 3 rd order only, i.e. coma-like aberrations. Figure 9.4(d) shows 5 th and higher order aberrations. Subject S1's natural optics shows high amount of aberrations in all orders, and there is a reduction of aberrations in all orders with RGP CL wear. 215
CHAPTER 9 All other subjects have a low amount of aberrations without CL, other than astigmatism, and the use of CLs does not change them significantly. The effect of RGP wear on 5 th and higher order terms (Fig. 9.4(d)) shows different trends across subjects: a decrease for S1, no difference for S3, and an increase for S2 and S4. Increase in the 5 th and higher order terms is curiously found in the same subjects who experienced an increase in 3 rd order terms and more systematic decentrations of the RGP lens. A possible increase of 3 rd and higher order terms due to decentrations had been predicted (Atchison, 1995, Ho et al., 2002) although this effect has proved more relevant for aspheric lenses. Figure 9.5 shows total and anterior surface 4 th order spherical aberration coefficient (Z 0 4) for the different subjects, with and without CL. As expected, despite intersubject differences in the amount of spherical aberration in the natural corneas, we obtained the same amount of spherical aberration for all lenses (increased with respect to natural values because the lenses were spherical). However, the total spherical aberration with CL is close to zero for all subjects. 9.5. DISCUSSION Fig. 9.5. Total and anterior surface 4 th order spherical aberration coefficient (Z 0 4) for the four subjects, with and without CL. 9.5.1. Aberration correction The principle of correction of corneal irregularities (and hence corneal aberrations) by RGP CLs has been explained by several authors (Griffiths et al., 1998, Atchison, 1995). The CL substitutes the anterior surface of the cornea with a polished regular surface. The main refraction is now produced at the anterior surface of the CL. Tear between lens and cornea fills in corneal irregularities. The power of the anterior surface of the cornea decreases to 11 %, as refraction indexes are almost the same (n tear = 1.336, n cornea =1.376). Therefore, the CL correction acts on corneal aberrations. We have found that RGP CLs are able to correct to some extent ocular aberrations. For the most aberrated eye, we found a decrease of RMS (excluding tilt and defocus) by a factor of 3 (or RMS decrement of 0.9 m). The improvement is not only due to astigmatism corrections. Non conventional aberrations were also significantly reduced: 3 rd and higher order RMS decreased by a factor of 2 (a decrement of 0.38 216
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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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CHAPTER 3 considering the same set
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CHAPTER 3 3.5.3 Impact of correctio
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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
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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Page 194: ON-EYE OPTICAL PERFORMANCE OF RIGID
Page 198 and 199: ON-EYE OPTICAL PERFORMANCE OF RIGID
Page 212: SOFT MONOFOCAL AND MULTIFOCAL CONTA
Page 216: SOFT MONOFOCAL AND MULTIFOCAL CONTA
Page 220 and 221: CORRELATION BETWEEN RADIUS AND ASPH
Page 230: CONCLUSIONS Conclusions This thesis
Page 233 and 234: CONCLUSIONS 5We have developed a pr
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Page 240 and 241: CONCLUSIONS FUTURE RESEARCH LINES T
Page 242 and 243: CONCLUSIONS LIST OF PUBLICATIONS AN
Page 244 and 245: REFERENCES References AIZAWA, D., S
Page 246 and 247: REFERENCES PHOTODECOMPOSITION (APD)
Page 248 and 249: REFERENCES DORRONSORO, C., CANO, D.
Page 250 and 251: REFERENCES GISPETS, J., ARJONA, M.
Page 252 and 253: 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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