Vehicle Headlight Halo Simulation Of Presbyopia Correcting Iols

To assess the halo produced by various presbyopia correcting IOL (PC-IOL) optical designs (diffractive, refractive, and wavefront shaping) using a bench set up simulating a vehicle headlight.

Alcon Vision LLC, Fort Worth, Texas.

Halos produced by the IOLs using a pinhole target simulating a 100 mm diameter headlight at 30 meters (4x objective) were measured using the high dynamic range halo measurement system.  IOLs were mounted in a model eye with IOL matched corneal spherical aberration, and an external pupil scaled to 4.5 mm at the IOL plane.  Since the area of the halo for some IOLs extends beyond the field of view of a 10x objective, images were measured also with a 4X microscope objective fitted to the camera. Light intensity was set so that the detector was just below saturation with a monofocal IOL, or about 20,000 cd/m2.  Using 4x images, area under the curve of light intensity plotted by visual angle up to 3 degrees was calculated.

The AUC of the halo image measured with a 4X objective ranged from 1007 (Monofocal IOL control) to 1896 (combined multifocal/EDF IOL).   In general, the non-diffractive IOLs produced smaller halos than the diffractive IOLs, with the wavefront shaping EDF IOL having an AUC (1012) closest to the monofocal control.

Simulated bench halos of non-diffractive PC-IOLs tend to be smaller and less intense than diffractive PC-IOLs.  Further clinical studies using standardized objective or subjective tools/questionnaires are required to understand how bench performance translates to patient experience with these IOLs.