Chromatic aberration compensation and focus extension in a first and second order diffractive intraocular lens of low addition
Session Details
Session Title: Moderated Poster Session: The New Enlarged Depth-of-Focus Technology
Venue: Poster Village: Pod 1
First Author: : M.Millan SPAIN
Co Author(s): : F. Vega M. Gil
Abstract Details
Purpose:
To describe analytically the spectral imaging properties of a 1st and 2nd order hybrid refractive-diffractive intraocular lens and prove them in optical bench. An example of such a diffractive intraocular lens (IOL) design can been found in the Tecnis Symfony ZXR00 IOL, commonly referred as to extended depth of focus (EDOF) IOL. As far as the authors know this is the first work that explains –both theoretical and experimentally- how the Symfony diffractive profile directs light energy into the distance and the intermediate foci for different red (R), green (G), and blue (B) wavelengths.
Setting:
Universitat Politècnica de Catalunya, BARCELONATECH. Barcelona, Spain.
Methods:
Using multiorder diffraction models we derived expressions for diffractive IOLs that operate with 1st and 2nd orders to contribute to the distance and intermediate foci, respectively, whereas conventional bifocals do with 0th and 1st orders. Power and energy efficiency versus wavelength and longitudinal chromatic aberration (LCA) in each focus were estimated by numerical simulation.
We measured experimentally the through-focus energy efficiency (TF-EE) of three Tecnis lenses for red(R), green(G) and blue(B) lights: the EDOF Symfony ZXR00, bifocal ZKB00 (+2.75D), and monofocal ZA9003. We compared their experimental imaging properties, between them and also with those predicted analytically.
Results:
An example of 1st and 2nd order hybrid refractive-diffractive IOL design with low +1.75D add power has been found in the Tecnis Symfony ZXR00 IOL. The numerical results for the RGB distance and intermediate powers, the RGB energy efficiencies and the LCA predicted by the model were in good agreement with the experimental measurements. In comparison with the monofocal and the +2.75D-bifocal counterparts, the low addition (+1.75D) of the Symfony diffractive profile provides focus extension from distance to intermediate vision with chromatic compensation, which is almost complete in the distance focus and very relevant in the intermediate focus.
Conclusions:
The imaging properties of the Symfony diffractive profile correspond to a design that uses the 1st and 2nd diffraction orders to form the distance and intermediate foci, respectively. The +1.75D add power provides focus extension from distance to intermediate vision with remarkable chromatic compensation. This fact, along with the aspheric design of the refractive base lens, surely contributes to enhance the imaging properties of the lens in distance and intermediate vision, but could be insufficient for some instances in near.
Financial Disclosure:
NONE
