Intraocular lenses replace the crystalline lens after cataract extraction. We evaluate in vivo the impact of cataract surgery and intraocular design in the patient´s optical performance.
In an earlier study we demonstrated (in vivo, as well as in vitro and computationally) that spherical IOLs induce positive spherical aberrations, proportionally to their power (Barbero et al. 2003).
Conversely, we have shown aspheric IOLs induce negative spherical aberration which compensates the positive spherical aberration of the cornea. We have shown the differences in optical quality and depth-of-focus in eyes implanted with aspheric or spherical IOLs. (Marcos et al. 2005). Interestingly, we have found that in eyes with aspheric IOLs, total horizontal coma is also compensated, due to a geometrical effect (Marcos et al. 2008)
Other factors that may influence optical degradation in pseudophakic patients are the corneal incision, and the misalignment of the IOL. We have measured the aberrations induced by corneal incision (Marcos et al. 2007) In addition, using Purkinje imaging (and also Scheimpflug imaging) we have evaluated in vivo the amount of tilt and decentration of implanted spherical and aspheric IOLs (de Castro et al. 2007).
We have developed customized eye models that predict optical aberrations in pseudophakic eyes with high accuracy. These models have allowed us to understand the relative contribution of different factors in optical degradation in pseudophakic eyes. (Rosales & Marcos, 2007).
In addition we have developed new analytical techniques for optimised design of intraocular lenses (Barbero and Marcos 2007
; Patent PCT/ES2008/070086
). New directions of research will include the development of customized monofocal IOLs and new multifocal designs.