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ABSTRACT: In vivo three-dimensional (3-D) anterior segment biometry before and after cataract surgery was analyzed by using custom high-resolution high-speed anterior segment spectral domain Optical Coherence Tomography (OCT). The system was provided with custom algorithms for denoising, segmentation, full distortion correction (fan and optical) and merging of the anterior segment volumes (cornea, iris, and crystalline lens or IOL), to provide fully quantitative data of the anterior segment of the eye. The method was tested on an in vitro artificial eye with known surfaces geometry at different orientations and demonstrated on an aging cataract patient in vivo. Biometric parameters CCT, ACD/ILP, CLT/ILT Tilt and decentration are retrieved with a very high degree of accuracy. IOL was placed 400 μm behind the natural crystalline lens, The IOL was aligned with a similar orientation of the natural lens (2.47 deg superiorly), but slightly lower amounts (0.77 deg superiorly). The IOL was decentered superiorly (0.39 mm) and nasally (0.26 mm).
Biomedical Optics Express 03/2013; 4(3):387-96. · 2.33 Impact Factor
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ABSTRACT: The improved designs of intraocular lenses (IOLs) implanted during cataract surgery demand understanding of the possible effects of lens misalignment on optical performance. In this review, we describe the implementation, set-up and validation of two methods to measure in vivo tilt and decentration of IOLs, one based on Purkinje imaging and the other on Scheimpflug imaging. The Purkinje system images the reflections of an oblique collimated light source on the anterior cornea and anterior and posterior IOL surfaces and relies on the well supported assumption of the linearity of the Purkinje images with respect to IOL tilt and decentration. Scheimpflug imaging requires geometrical distortion correction and image processing techniques to retrieve the pupillary axis, IOL axis and pupil centre from the three-dimensional anterior segment image of the eye. Validation of the techniques using a physical eye model indicates that IOL tilt is estimated within an accuracy of 0.261 degree and decentration within 0.161 mm. Measurements on patients implanted with aspheric IOLs indicate that IOL tilt and decentration tend to be mirror symmetric between left and right eyes. The average tilt was 1.54 degrees and the average decentration was 0.21 mm. Simulated aberration patterns using custom models of the patients eyes, built using anatomical data of the anterior cornea and foveal position, the IOL geometry and the measured IOL tilt and decentration predict the experimental wave aberrations measured using laser ray tracing aberrometry on the same eyes. This reveals a relatively minor contribution of IOL tilt and decentration on the higher-order aberrations of the normal pseudophakic eye.
Clinical and Experimental Optometry 10/2010; 93(6):400 - 408. · 1.05 Impact Factor
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ABSTRACT: Infections caused by quinolone-resistant Neisseria gonorrhoeae are increasing worldwide. Although mostly mild and uncomplicated, serious infections causing severe morbidity are occasionally observed. We report 2 cases of sexually transmitted keratoconjunctivitis in adults resulting in severe visual disturbance.
Sexually transmitted diseases 05/2010; 37(5):340-1. · 2.58 Impact Factor
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ABSTRACT: To study the effect of cataract surgery through 3.2 mm superior incisions on corneal aberrations with 2 types of monofocal intraocular lenses (IOLs) with an aspherical design.
Instituto de Optica, Consejo Superior de Investigaciones Científicas, and Fundación Jiménez Díaz, Madrid, Spain.
Corneal topography of 43 eyes was obtained before and after small corneal incision cataract surgery. Twenty-two eyes had implantation of a Tecnis Z9000 silicone IOL (Advanced Medical Optics) and 21 had implantation of an AcrySof IQ SN60WF acrylic IOL (Alcon Research Labs) using the recommended injector for each IOL type. The intended incision size (3.2 mm) was similar in the 2 groups. Corneal aberrations were estimated using custom-developed algorithms (based on ray tracing) for 10.0 mm and 5.0 mm pupils. Comparisons between preoperative and postoperative measurements and across the groups were made for individual Zernike terms and root-mean-square (RMS) wavefront error.
The RMS (excluding tilt and defocus) did not change in the AcrySof IQ group and increased significantly in the Tecnis group with the 10.0 mm and 5.0 mm pupil diameters. Spherical aberration and coma-like terms did not change significantly; however, vertical astigmatism, vertical trefoil, and vertical tetrafoil changed significantly with surgery with the 10.0 mm and 5.0 mm pupil diameters (P<.0005). The induced wave aberration pattern for 3rd- and higher-order aberrations consistently showed a superior lobe, resulting from a combination of positive vertical trefoil (Z(3)(-3)) and negative tetrafoil (Z(4)(4)). The mean vertical astigmatism increased by 2.47 microm +/- 1.49 (SD) and 1.74 +/- 1.44 microm, vertical trefoil increased by 1.81 +/- 1.19 microm and 1.20 +/- 1.34 microm, and tetrafoil increased by -1.10 +/- 0.78 microm and -0.89 +/- 0.68 microm in the Tecnis group and AcrySof IQ group, respectively. There were no significant differences between the corneal aberrations in the 2 postoperative groups, although there was a tendency toward more terms or orders changing statistically significantly in the Tecnis group, which had slightly higher amounts of induced aberrations.
Cataract surgery with a small superior incision induced consistent and significant changes in several corneal Zernike terms (vertical astigmatism, trefoil, and tetrafoil), resulting in a significantly increased overall corneal RMS wavefront error. These results can be used to improve predictions of optical performance with new IOL designs using computer eye models and identify the potentially different impact of incision strategies on cataract surgery.
Journal of Cataract [?] Refractive Surgery 02/2007; 33(2):217-26. · 2.26 Impact Factor
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ABSTRACT: Corneal and ocular aberrations were measured in a group of eyes before and after cataract surgery with spherical intraocular lens (IOL) implantation by use of well-tested techniques developed in our laboratory. By subtraction of corneal from total aberration maps, we also estimated the optical quality of the intraocular lens in vivo. We found that aberrations in pseudophakic eyes are not significantly different from aberrations in eyes before cataract surgery or from previously reported aberrations in healthy eyes of the same age. However, aberrations in pseudophakic eyes are significantly higher than in young eyes. We found a slight increase of corneal aberrations after surgery. The aberrations of the IOL and the lack of balance of the corneal spherical aberrations by the spherical aberrations of the intraocular lens also degraded the optical quality in pseudophakic eyes. We also measured the aberrations of the IOL in vitro, using an eye cell model, and simulated the aberrations of the IOL on the basis of the IOL's physical parameters. We found a good agreement among in vivo, in vitro, and simulated measures of spherical aberration: Unlike the spherical aberration of the young crystalline lens, which tends to be negative, the spherical aberration of the IOL is positive and increases with lens power. Computer simulations and in vitro measurements show that tilts and decentrations might be contributors to the increased third-order aberrations in vivo in comparison with in vitro measurements.
Journal of the Optical Society of America A 10/2003; 20(10):1841-51. · 1.56 Impact Factor
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Susana Marcos,
Sergio Barbero,
Alberto de Castro,
Carlos Dorronsoro,
Elena García de la Cera,
Gemma Heras,
Jesús Merayo-Lloves, Ignacio Jiménez-Alfaro,
Lourdes Llorente,
Sergio Ortiz,
José Requejo-Isidro,
Patricia Rosales,
Lucie Sawides
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ABSTRACT: The Visual Optics and Biophotonics Lab (Institute of Optics, CSIC) develops non-invasive optical techniques for the evaluation of the normal and pathological eye. We present experimental developments and recent results of applications in the fields of myopia and presbyopia and their correction techniques, as well as work in progress and future directions. El Laboratorio de Óptica Visual y Biofotónica del Instituto de Óptica del CSIC desarrolla técnicas ópticas no invasivas para la evaluación del ojo normal y patológico. Presentamos desarrollos experimentales y resultados recientes de aplicaciones en los campos de la miopía, presbicia y sus técnicas de corrección, así como trabajo en curso y direcciones futuras. La financiación reciente del grupo viene dada por dos proyectos del Ministerio de Educación y Ciencia (BFM2002-02638, FIS2005-04382), tres proyectos de la Comunidad Autónoma de Madrid (CAM08.7/0010.1/2000, CAM08.7/004.1/2003, GR/SAL/0387/2004), un Proyecto de Cooperación España-EEUU, una Acción Integrada, siete contratos de investigación con la industria, y un European Young Investigator Award. Además se han concedido a los distintos miembros del grupo becas y contratos postdoctorales I3P-CSIC, becas FPI, FPU, CSIC-Unidades Asociadas y de la Comunidad de Madrid. Peer reviewed
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ABSTRACT: To compare experimental optical performance in eyes implanted with spherical and aspheric intraocular lenses (IOLs).
Corneal, total, and internal aberrations were measured in 19 eyes implanted with spherical (n=9) and aspheric (n=10) IOLs. Corneal aberrations were estimated by virtual ray tracing on corneal elevation maps, and total aberrations were measured using a second-generation laser ray tracing system. Corneal and total wave aberrations were fit to a Zernike polynomial expansion. Internal aberrations were measured by subtracting corneal from total wave aberrations. Optical performance was evaluated in terms of root-mean-square (RMS) wavefront error and Strehl ratio (estimated from the modulation transfer function). Depth-of-field was obtained from through-focus Strehl estimates from each individual eye.
Corneal aberrations increased after IOL implantation, particularly astigmatism and trefoil terms. Third and higher order RMS (and the corresponding Strehl ratio) were significantly better in eyes with aspheric IOLs than with spherical IOLs; however, this tendency was reversed when astigmatism was included. Spherical aberration was not significantly different in eyes with aspheric IOLs, whereas it was significantly positive in eyes with spherical IOLs. Third order aberrations were not significantly different across groups. Depth-of-field was significantly larger in eyes with spherical IOLs. Spherical IOLs showed better absolute optical quality in the presence of negative defocus >1.00 D.
Our study shows a good degree of compensation of the corneal spherical aberration in eyes implanted with aspheric IOLs, as opposed to eyes implanted with spherical IOLs. Other sources of optical degradation, both with aspheric and spherical IOLs, are non-symmetric preoperative corneal aberrations, incision-induced aberrations, and third order internal aberrations. Although best corrected optical quality is significantly better with aspheric IOLs, tolerance to defocus tended to be lower.
Journal of refractive surgery (Thorofare, N.J.: 1995) 21(3):223-35. · 2.54 Impact Factor
