Associate researcher.
(BSc Physics 1999, PhD Visual Sciences 2004).
I received my degree in Physics, with specific training in Optics, at the University of Zaragoza (1999),
after attending the first three years of studies at University of Valladolid. I started my pre-doctoral
research (10/99) in the visual optics field at the recently created Visual Optics and Biophotonics
laboratory, Instituto de Óptica (CSIC), under the supervision of professor Susana Marcos.
My research was initially funded with programs co-funded by industry and the Spanish
Ministerio de Educación y Ciencia.
During my first years of research (99-02) I developed new experimental techniques for measuring
optical aberrations of the cornea and crystalline lens. I collaborated in the experimental implementation of
a ray-tracing technique to measure the optical aberrations of the human eye. As a result of this
methodological research I published two papers as first author[1, 2] (40 citations). Using the new
methodology I participated in several studies of clinical application: Measurement of optical
aberrations induced by laser refractive surgery[3, 4] (196 citations), and optical quality analysis
of rigid gas permeable contact lens wearers[5] (7 citations). In the framework of laser surgery
research I collaborated in a computational study on corneal ablation algorithms[6, 7] (15 citations).
Among the clinical and technological oriented studies, I emphasize my implication in a novel
research on intraocular lenses implanted after cataract surgery. We measured, for the first time in vivo
(besides in vitro measurements and simulations), the optical quality of spherical intraocular lenses (IOL).
We found that spherical IOLs induced spherical aberration[8] (17 citations). In a subsequent
study we compared spherical versus aspheric IOLs [9] (9 citations). During my PhD I worked as
a visiting scholar (23/06/03-23/08/03) at School of Optometry (University of Houston) with Prof. Adrian Glasser,
I innovated new tomography techniques for the reconstruction of the gradient refractive index structure
of the human crystalline lens[10].
My PhD lecture (16-02-04) received the Doctoral Thesis Extraordinary Award at Universidad de
Valladolid (2005). In April 2004 I joined the Visual Optics Group at the School of Optometry
(Indiana University) under the supervision of Prof. Larry Thibos, initially funded with a research
contract from a USA federal NIH grant and later with a Fulbrigth fellowship (10/04-06/06) through
the Spanish Ministerio de Eduación y Ciencia.
In Indiana I worked in two research topics:
1) Study and experimental implementation of new measurement and reconstruction wavefront techniques.
Some human ocular pathologies involving the human tear film are revealed by small-scale spatial
wavefront perturbations. In order to measure these small perturbations I implemented a curvature
sensor and performed a detailed error analysis. I proposed new image processing techniques
to correct detection errors[11]. Perhaps, the most relevant scientific achievement during my
post-doctoral research at Indiana University was the proposal of a new wavefront measurement
and reconstruction technique based on the combined measurement of the wavefront gradient
and laplacian. This work was done in collaboration with professor Jacob Rubinstein (Mathematics
Department, Indiana University). Because of the technological relevance of this work, we have
started the application of a US patent[12]. Furthermore, the work has been published in one of the
journals with highest impact factor in optics: Optics Letters[13].
2) Human eye optical modelling with gradient refractive index structures.
I worked in a new multilayer model of the human cornea and tear film, using a gradient refractive
index structure and subsequently evaluating its optical implications in paraxial refractive power
and spherical aberration[14].
I also worked in collaboration with Prof. David Atchison (Queensland University of Technology)
and Prof. George Smith (The University of Melbourne), both from Australia. We derived the
equations to estimate changes in the spherical aberration of the human with image plane shifts [15].
In 2006 I joined back the Visual Optics laboratory (CSIC), led by Prof. Susana Marcos, funded with
I3P research contract (CSIC). My current research topics are: 1) Development of new intraocular
lens designs using analytical mathematical tools[16]. 2) Eye modelling with gradient-index
structures, in collaboration with the GRIN optics group at Universidad de Santiago de
Compostela [17]. 3) Experimental implementation of a ray-tracing technique to measure on and
off-axis optical aberrations of human crystalline lenses. We are developing tomography
algorithms for the reconstruction of the gradient refractive index structure of crystalline lenses in vivo[18].
In summary:
1. I have been awarded with 4 pre-doctoral fellowships or contracts (industrially oriented
and FPU), one post-doctotral fellowship (Fulbright) and two post-doctoral contracts (USA
government and I3P-CSIC)
2. I have worked with two different Spanish researching groups (located at CSIC and
Universidad de Santiago de Compostela), two USA groups (located at Indiana
University and University of Houston) and one Australian group (Queensland University
of Technology and University of Melbourne).
3. I have been involved in three research grants funded by public institutions and
4 industrial contracts.
4. I have presented 33 poster/presentations in scientific meetings, two of them invited lectures.
5. I have published 16 original referred publications that have been cited 326, with a 9 h-index.
I have prepared a provisional patent in USA.
References
1. Barbero, S., et al., Validation of the estimation of corneal aberrations from videokeratography in
keratoconus. Journal Of Refractive Surgery, 2002. 18(3): p. 263-270.
2. Barbero, S., S. Marcos, and J. Merayo-Lloves, Corneal and total optical aberrations in a unilateral
aphakic patient. Journal Of Cataract And Refractive Surgery, 2002. 28(9): p. 1594-1600.
3. Moreno-Barriuso, E., et al., Ocular aberrations before and after myopic corneal refractive surgery:
LASIK-induced changes measured with laser ray tracing. IOVS, 2001. 42(6): p. 1396-1403.
4. Marcos, S., et al., Optical response to LASIK surgery for myopia from total and corneal
aberration measurements. IOVS, 2001. 42(13): p. 3349-3356.
5. Dorronsoro, C., et al., On-eye measurement of optical performance of rigid gas permeable contact lenses
based on ocular and corneal aberrometry. Optometry And Vision Science, 2003. 80(2): p. 115-125.
6. Cano, D., S. Barbero, and S. Marcos, Comparison of real and computer-simulated outcomes of LASIK
refractive surgery. JOSA-A, 2004. 21(6): p. 926-936.
7. Marcos, S., D. Cano, and S. Barbero, Increase in corneal asphericity after standard laser in situ
keratomileusis for myopia is not inherent to the Munnerlyn algorithm. Journal Of Refractive Surgery, 2003.
19(5): p. S592-S596.
8. Barbero, S., S. Marcos, and I. Jimenez-Alfaro, Optical aberrations of intraocular lenses measured in
vivo and in vitro. JOSA-A, 2003. 20(10): p. 1841-1851.
9. Marcos, S., S. Barbero, and I. Jimenez-Alfaro, Optical quality and depth-of-field of eyes implanted with
spherical and aspheric intraocular lenses. Journal Of Refractive Surgery, 2005. 21(3): p. 223-235.
10. Barbero, S., et al., Accuracy and possibilities for evaluating the lens gradient-index using a ray
tracing tomography global optimization strategy, in ARVO meeting. IOVS. 2004: Fort Lauderdale, Florida, USA.
11. Barbero, S. and L.N. Thibos, Error analysis and correction in wavefront reconstruction from the
transport-of-intensity equation. Optical Engineering, 2006. 45(9): p. 094001.
12. Barbero, S., L.N. Thibos, and J. Rubinstein, Wavefront sensing and reconstruction from gradient and
laplacian data measured with a Hartmann-Shack sensor, I.U.R.a.T. Corporation, Editor: USA.
13. Barbero, S., J. Rubinstein, and L.N. Thibos, Wavefront sensing and reconstruction from gradient and
Laplacian data measured with a Hartmann-Shack sensor. Optics Letters, 2006. 31(12): p. 1845-1847.
14. Barbero, S., Refractive power of a multilayer rotationally symmetric model of the human cornea and
tear film. JOSA-A, 2006. 23(7): p. 1578-1585.
15. Smith, G., D.A. Atchison, and S. Barbero, Effect of defocus on on-axis wave aberration of a
centered optical system. JOSA-A, 2006. 23(11): p. 2686-2689.
16. Barbero, S. and S. Marcos. Analytical tools for intraocular lens design with aspheric surfaces. in
Investigative Ophthalmology & Visual Science. 2007. Fort Lauderdale, Florida, USA.
17. Barbero, S., et al., The role of gradient-index structures of the human eye in paraxial power changes
with age. Vision Research, Submitted.
18. De Castro, A., S. Barbero, and S. Marcos. A reconstruction technique to estimate the gradient-index
distribution of the crystalline lens using ray aberration data in vivo. in ARVO meeting. IOVS. 2007.
Fort Lauderdale, Florida, USA.