Abstract
Purpose :
In standard optical bench settings, the point light source for the measurement of three-dimensional point spread functions (3D-PSF) appears to be at infinity distance. The 3D-PSF serves as a key parameter, enabling a comprehensive characterization of the IOL, including the assessment of its energy efficiency, defined as the ratio of constructive to total light. However, in real life, objects have different distances leading to different light fields entering an eye. The consequences for the 3D-PSF are commonly neglected. The optical bench developed in this study incorporates an automated Badal optic to acquire the 2D-PSF at different light source distances giving a more accurate view of the optical imaging performance of lenses.
Methods :
To accurately account for object-specific distances, the light source is adjusted to various distances using computer-controlled Badal optics. For each object's distance, a 2D-PSF is recorded. Additionally, an integrated automated filter wheel allows the simulation of different pupil sizes, and an objective setup with three magnifications (10, 20 and 40x). The optical bench was fully simulated in OpticStudio. Control of the Badal lens, filter wheel, and CMOS camera was programmed in LabView (National Instruments), and data analysis was performed in Mathematica.
Results :
The development enables the automated imaging of a point light source at various distances. The pupil is imaged telescopically into the IOL, illuminating only the desired part of the IOL. The Badal optics and the resulting different beam divergences cause intensity variations, which are corrected by a previously experimentally determined distance-dependent factor. Measurements demonstrate the potential to capture large-scale halo phenomena while still depicting the central 2D-PSF in high resolution.
Conclusions :
This new development represents a further step in the realistic measurement of the imaging properties of IOLs. The high level of automation is indispensable for practical reasons. Existing algorithms have been tailored to the generated data. A direct comparison of measurements from the optical bench without and with Badal optics will reveal whether the common approximation is justified.
This abstract was presented at the 2024 ARVO Annual Meeting, held in Seattle, WA, May 5-9, 2024.