Ronchi test for testing the powers of bifocal intraocular lenses

The Ronchi test is one of the simplest and most powerful methods for evaluation and measuring the spherical aberration of an optical system and is an accurate method for measuring the focal length of an IOL (Carretero et al., 1992, 1993). The accuracy of lens power specification is a crucial factor for bifocal intraocular lenses (IOLs). Therefore, the powers of these IOLs must be tested to verify that the lenses have been manufactured according to the design. In this paper we suggest the use of the Ronchi test for testing the two powers of bifocal IOLs.