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.

Le Grand eye for the study of ocular chromatic aberration.

In this technical note we study the prediction of ocular chromatic aberration which provides Le Grand's complete theoretical eye model. Theoretical computations of the longitudinal chromatic aberration are lower than experimental results. However, we show that experimental results of the chromatic difference of position (CDP) agree with theoretical predictions. The fit of the CDP for this model is practically the same as the one obtained for the Thibos reduced eye.