Visualization Of The Ray Propagation Through Extended-Depth-Of-Focus Iols

AcrySof IQ Vivity is a recently introduced intraocular lens (IOL) with an extended depth of focus (EDoF). This is a non-diffractive IOL that uses wavefront-shaping technology to provide adequate vision for pseudophakic patients at infinity and across intermediate ranges. We performed a ray-propagation visualization through this new lens and compared its light-distribution profile with two diffractive EDoF lenses and a monofocal control.

In this laboratory investigation, three EDoF models were compared - a non-diffractive AcrySof IQ Vivity (Alcon Inc.), as well as diffractive Symfony ZXR00 (Johnson & Johnson Vision) and AT Lara 829 MP (Carl Zeiss Meditec, Germany) IOLs. In our optical-bench ray-visualization setup, 520-nm laser light was projected through a model cornea. The IOL under test was submerged in a fluorescein solution. Light propagation was captured with a camera mounted on a surgical microscope. Ray visualization was also performed on a monofocal lens (AcrySof IQ SN60WF, Alcon Inc.).

The monofocal control showed one focus corresponding to the IOL nominal power. The Vivity created an extended focus area seen in the rays' convergence along the optical axis and its light-intensity profile. The ray-visualization technique revealed two distinct foci of the diffractive models. In the Symfony, a minimally higher light-intensity value was found at the intermediate than the far distance.

The green-laser-light evaluation demonstrated an extended range of focus of the EDoF IOLs; however, only the non-diffractive model presented one continuous light-intensity peak. By contrast, two distinct foci were observed in the ray propagation of the diffractive IOLs.