Light is scattered within an IOL by every diffractive step.
Considerable additional light scattering is caused by the manufactured imperfections of these steps on multiple points.
Therefore not only the quality but also the quantity of the manufactured steps has a great impact on light scattering and loss of light energy.
Figure 1a and 1b demonstrate the difference in light scattering and energy loss on two separate diffractive IOL profiles:
Figure 1a: Light scattering caused by 16 diffractive steps.
Figure 1b: LIBERTY optic with 7 diffractive steps. Moderate light scattering.
7 STEPS TO TRIFOCAL PERFECTION
The 4 charts below show the Useful Light Distribution in % of LIBERTY and 3 competitors depending on the aperture [mm]* :
* Based on Zemax simulation results, PMTF calculation method and on Strehl ratio calculated from Zemax simulated MTF values.
LIBERTY provides the highest light distribution:
1) AT NEAR in photopic conditions
2) AT FAR in scotopic conditions
3) Leaving an optimal amount of light energy for INTERMEDIATE VISION: