Alberto de Castro is interested in imaging the human eye to understand its properties and behavior. With age, some vision is lost but the knowledge of the characteristics in young eyes can be used to design corrections. As a PhD Student in Susana Marcos’ lab, he studied the gradient refractive index of the crystalline lens using Optical Coherence Tomography images. He then learned how to image the retina in living eyes with techniques that combine adaptive optics and confocal microscopy with Stephen Burns and studied the possibility of imaging through a cataractous lens in Pablo Artal’s lab.

During the first part of his research project, Dr. de Castro developed routines to use the information from three-dimensional OCT images obtained from patients to build personalized pseudophakic eye models. Algorithms developed on these models are being used to study the impact of new intraocular lens designs. In the second part of the project, Dr. de Castro focused on the development of a new generation of intraocular lenses that will be able to change its power.

Project Abstract

The crystalline lens changes with age at a certain age loses its ability to deform when the ciliary muscle relaxes. This condition, known as presbyopia, is usually treated with optical corrections such as multifocal lenses. However, the possibility of substituting the rigid crystalline lens with an accommodative intraocular lens has drawn a lot of interest. The problem needs complex biomechanics and optical design to produce the desired behavior in the eye. This research program will allow the development of an anterior segment imaging system that will be used to evaluate the behavior of these implants inside the eye and to explore the possibility of selecting the best possible implant before surgery. In addition, a recently proposed technology used to engage the lens haptics on to the capsular bag, photobonding, will be explored with a confocal microscope. The information of the capsule obtained before and after the bonding process will improve the knowledge on the tension that the accommodative plant and the capsule are able to generate and how these forces can be used in an implant to change its shape. With these two imaging techniques, we envision an improvement on the available methods to evaluate and design accommodative intraocular lenses.

More information about the project

  • A. de Castro, J. Birkenfeld, B. Maceo Heilman, M. Ruggeri, E. Arrieta, J.M. Parel, F. Manns, and S. Marcos. “Off-axis optical coherence tomography imaging of the crystalline lens to reconstruct the gradient refractive index using optical methods”, Biomedical Optics Express (7) 3622, 2019. Open Access link here
  • A. de Castro, E. Martinez Enriquez, P. Perez Merino, M. Velasco, L. Revuelta, S. McFadden and S. Marcos. “Crystalline lens gradient refarctive index distribution int he guinea pig”, Ophthalmic and Physiological Optics 2020
  • E. Martinez-Enriquez, A. de Castro, A. Mohamed, N. Sravani, M. Ruggeri, F. Manns and S. Marcos. “Age- related changes of the 3-dimensional full shape of the isolated human crystalline lens.” Investigative Ophthalmol and Vision Science, 2020. Open Access link here
  • E. Martinez-Enriquez, A. de Castro, S. Marcos “Eigenlenses: an eigenvectors-based model for full crystalline lens shape description”. Open Access link here
  • J. Birkenfeld, A. Varea, J. A. Germann, A. de Castro, A. Curatolo, S. Marcos “Porcine models for localized changes in corneal biomechanics and their applications” (in preparation).
  • G. Muralidharan, J. Birkenfeld, M. Vinas, A. Curatolo, E. Martinez-Enriquez, A. de Castro, S. Marcos, “Myopia changes in crystalline lens accommodation state when using multifocal corrections” (in preparation)