Author: Georgios Zoulinakis, University of Valencia
The power of an intraocular lens (IOL) is defined by its refractive index, the refractive index of the aqueous, the thickness and the power of the two surfaces of the lens. The refractive index of an IOL is fixed between 1,45 and 1,55. The refractive index of the aqueous is also fixed at 1,37. The question is about the effect of the geometric parameters of the lens on the optical quality that it provides. If we suppose that the thickness of the lens is also fixed, around 1 mm, only the two surfaces remain to be changed. A new project has started in the University of Valencia, about the optical quality and the visual performance of many IOLs with the same total power, changing only the anterior and posterior surfaces’ powers. In this project we have taken categories of lenses with power between -10 and 40 Diopters. In all lenses we have chosen a standard thickness, refractive index and position behind the pupil. The powers of the anterior and posterior surfaces are changed by changing the radius of curvature of both surfaces in respect, so that the total power remains the same.
Our results up to now concern only spherical surface lenses. It seems that as the power of the anterior surface is growing up to between 70% - 90% of the total power of the IOL, the total RMS error (Root Mean Square) and spherical aberration of the whole system of the eye model including the IOL is getting smaller.
Top: image on retinal plane of the model Bottom: image on retinal plane of the model.