Tesina realitzada en col.laboració amb City University London. Department of Optometry & Visual Science

The spherical aberration of an Akreos ADAPT AO aberration-free intraocular lens was studied using a point-diffraction interferometer and the ocular aberrations of patients undergoing pre-operative assessment for implantation with this lens were obtained with a Scheimpflug system (Pentacam) and Hartmann-Shack aberrometer (Zywave). Measured values for the Z(4,0) coefficient were 0.028 μm +/- 0.019 and 0.021 μm +/- 0.013 for the Akreos lens and an equivalent spherically-surfaced intraocular lens when measured in air with a collimated beam at 543.1nm. Anterior and posterior corneal aberrations on 11 subjects demonstrated that the posterior cornea contributed 1.2 times the spherical aberration of the anterior surface of the cornea. In addition, lenticular spherical aberration values were found to be -1.543 μm +/- 0.29 when corneal aberration data was combined with whole eye aberrometry. In air interferometry did not demonstrate lower values of spherical aberration for the aspheric Akreos lens as expected. This may have been due to liquid film effects on the surfaces negating the aspheric profile. Point-diffraction interferometry was found to be limited in the amount of tilt that could be produced to generate tilt fringes for analysis. The corneal posterior surface spherical aberration is not negligible and should be taken into account when designing and selecting aspheric intraocular lenses. Customized intraocular lenses would provide the optimal result for all patients.