Combining in vitro test methods for measuring light scatter in intraocular lenses

Intraocular lenses (IOLs) are designed for implantation for vision correction following cataract removal. The IOL typically replaces a cataractous natural lens that exhibits very high levels of light scattering. The amount of scattering is significantly reduced with an IOL, though it is rarely quantified and both the surface and the bulk of the intraocular lens may contribute to light scatter at some level, and in some cases potentially affecting patients' post-operative quality of vision. The purpose of this paper is to describe two complementary in-vitro quantitative methods for measuring light scatter caused by IOLs. The first method directly measures light scatter from the lens in one plane for angles larger than two degrees. The second method measures light scatter in an eye model including the focal point out to three degrees in the image plane. The measured amount of light scatter from an IOL is typically lower than that found in healthy donor crystalline lenses of various ages that are used as a basis for comparison.