Extended depth of focus and multifocal lenses, including contact and intraocular ones, tend to create a halo effect in certain light conditions. It can be distracting and even dangerous, particularly at dusk and night when looking at bright point sources such as traffic lights. Researchers from Bar-Ilan University in Israel have come upon a way of substantially reducing this halo effect without making the manufacturing of the lenses any more difficult.
The technique requires a precise smoothing of the structures on the surface of the lenses. This was achieved by initially building a mathematical model of how light has to pass through the lens, followed by numerical simulations, and then actually creating the lenses. These were then implanted in 16 volunteers who rated the halos they saw. Impressively, the results demonstrated a substantial reduction in the size of the halos compared to commercially available lenses.
Study in Optics Communications: Ophthalmic halo reduced lenses design…