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 Sergio Barbero

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.   




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.