Abstract
Purpose: :
The purpose of this study is provide a matrix–based calculation strategy of tracing a bundle of rays through an optical system and apply this method to a pseudophakic model eye containing second order surfaces.
Methods: :
We applied this straightforward matrix–based strategy to the Le Grand schematic model eye modified by Kooijman, extracted the crystalline lens and inserted an artificial IOL with a spherical or aspherical front surface and a spherical back surface. The conc constant was selected to minimize blur in the best focus plane. Then these lenses were decentred by 1 mm inferiorly to study the effect of decentred spherical or aspherical lens implants on the image property.
Results: :
We calculated the ray spot diagram for the best focus, parafocal planes in front of and behind the focus and at the paraxial focus. We found, that the optical quality (ray scatter) of the centred aspherical lens can be improved significantly with an aspherical IOL at the best focus, but at the parafocal and paraxial planes the aspherical and the spherical IOLs are comparable. After decentration of the IOL the spherical lens shows superior image quality compared to the aspherical IOL at the best focus as well as the parafocal and the paraxial focal plane.
Conclusions: :
Restricting to quadric surfaces raytracing through an optical system can be performed with simple matrix strategy. With this method, the image properties of centred and decentred spherical, aspherical and toric lenses may be analyzed efficiently.
Keywords: optical properties • intraocular lens • visual acuity