Effect on laser-ablation algorithms of reflection losses and nonnormal incidence on the anterior cornea

Jiménez, José María López; Anera, Rosario G.; Barco, Luis Jiménez del; Hita, E.

doi:10.1063/1.1502192

Cited by 64 publications

(56 citation statements)

References 3 publications

(2 reference statements)

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“…Special ablation patterns were designed to preserve the preoperative level of high-order aberrations 17 , 18 , 19 , if the best corrected visual acuity, in this patient, has been unaffected by the pre-existing aberrations 20 . Thus to compensate for the aberrations induction observed with other types of profile definitions 21 , some of those sources of aberrations are those ones related to the loss of efficiency of the laser ablation for non-normal incidence 22,23,24 . Methods for determining functional optical zones have been used previously.…”

Section: Aspheric Optical Zones and The Effective Optical Zonementioning

confidence: 99%

Aspheric Refractive Correction of Irregular Astimatism

Camellin¹,

Arba-Mosquera²

2012

Astigmatism - Optics, Physiology and Management

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Section: Aspheric Optical Zones and The Effective Optical Zonementioning

confidence: 99%

Aspheric Refractive Correction of Irregular Astimatism

Camellin¹,

Arba-Mosquera²

2012

Astigmatism - Optics, Physiology and Management

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“…In recent work, Jime´nez et al deduced an analytical expression to determine the change in corneal asphericity after LASIK surgery [22]. Their calculation is based on the algorithm given by Munnerlyn's paraxial formula and can be modified in order to account for the effects that reflection losses and non-normal incidence on the anterior cornea have on laser ablation [23][24][25][26]. In this way, the change in asphericity can be easily implemented in a personalized model by direct application of the equations deduced by these authors.…”

Section: Introductionmentioning

confidence: 99%

Corneal changes induced by laser ablation: study of the visual-quality evolution by a customized eye model

Ortiz

Anera

Saiz

et al. 2006

Journal of Modern Optics

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This study focuses on the changes induced in both the asphericity and homogeneity of the cornea for a group of myopic eyes undergoing LASIK surgery. Eyes were characterized by a Kooijman-based customized eye model in which changes were introduced in the form of Gaussian-distributed refractive-index variations of given correlation length for the inhomogeneities and in the form of an expression, based on the modified Munnerlyn's paraxial formula, for the post-LASIK asphericity. Visual quality was evaluated in terms of the Modulation Transfer Function and the Point-Spread Function. The results show that, on average, the evolution of visual acuity is consistent with the change in corneal asphericity, while the evolution of contrast sensitivity requires a loss in corneal homogeneity in order to be explained. By including both effects in the model, the overall model performance in predicting visual quality is improved.

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“…For example, some of those sources of aberration are related to the loss of efficiency of the laser ablation for non-normal incidence. [18][19][20] …”

Section: Introductionmentioning

confidence: 99%

Bilateral Symmetry before and Six Months after Aberration-Free™ Correction with the SCHWIND AMARIS TotalTech Laser: Clinical Outcomes

Arbelaez

Vidal

Arba-Mosquera

2010

Journal of Optometry

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PURPOSE:To compare the preoperative and postoperative bilateral symmetry between OD and OS eyes that have undergone femto-LASIK using the Ziemer LDV femtosecond laser system, the SCHWIND AMARIS Excimer Laser and the Aberrationfree TM profiles implemented in the SCHWIND Custom Ablation Manager software. METHODS: A total of 25 LASIK patients were bilaterally evaluated at the six-month follow-up visit. In all cases standard examinations, pre-and postoperative analysis with corneal wavefront topography (OPTIKON Scout) were performed. Aberration-free TM aspheric treatments were devised using the Custom Ablation Manager software and ablations were performed by means of the SCHWIND AMARIS flying-spot excimer laser system (both SCHWIND eyetech-solutions). In all cases LASIK flaps were created using an LDV femtosecond laser (Ziemer Group). The OD/OS bilateral symmetry was evaluated in terms of corneal wavefront aberration. RESULTS: Preoperatively, 11 Zernike terms showed significant bilateral (OS-vs.-OD) symmetry, and only 6 Zernike terms were significantly different. Overall, 23 out of the 25 patients showed significant bilateral symmetry, and only 2 out of 25 patients showed significant differences. None of the aberration metrics changed from pre-to postoperative values by a clinically relevant amount. At the 6-month postoperative visit, 12 Zernike terms showed significant symmetry, and 8 terms were significantly different. Overall, 22 out of 25 patients showed significant bilateral symmetry (OS vs. OD), and only 3 out of 25 patients showed significant differences. Also, this postoperative examination revealed that 6 Zernike terms lost significant OS-vs.-OD symmetry, but 4 Zernike terms gained significant symmetry. Finally, 4 patients lost significant bilaterality, and 2 patients gained significant bilaterality: bilateral symmetry between eyes was better maintained in those patients with a clear preoperative bilateral symmetry. CONCLUSIONS: Aberration-Free Treatments with the SCHWIND AMARIS did not induce clinically significant aberrations, maintained the global OD-vs.-OS bilateral symmetry, as well as the bilateral symmetry between corresponding Zernike terms (which influences binocular summation). RESUMEN OBJETIVO:Comparar la simetría bilateral (OD-OS) preoperativa y postoperativa, en ojos sometidos a una operación de femto-LASIK donde se empleó el sistema láser de femtosegundos Ziemer LDV, el láser de excímero SCHWIND AMARIS y donde se implementaron perfiles de ablación Aberration-free TM (sin aberraciones) en el software de control del láser (SCHWIND Custom Ablation Manager). MÉTODOS: Se evaluaron bilateralmente un total de 25 pacientes de LASIK transcurridos 6 meses de la operación. En todos los casos se llevó a cabo una revisión estándar, y se realizaron medidas pre-y postoperativas de topografía corneal (OPTIKON Scout). Se diseñaron tratamientos asféricos de tipo Aberration-free TM utilizando el software de control del láser, denominado Custom Ablation Manager. La ablación se realizó mediante el sistem...

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Effect on laser-ablation algorithms of reflection losses and nonnormal incidence on the anterior cornea

Cited by 64 publications

References 3 publications

Aspheric Refractive Correction of Irregular Astimatism

Aspheric Refractive Correction of Irregular Astimatism

Corneal changes induced by laser ablation: study of the visual-quality evolution by a customized eye model

Bilateral Symmetry before and Six Months after Aberration-Free™ Correction with the SCHWIND AMARIS TotalTech Laser: Clinical Outcomes

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