Kerr constant of vesicle-like droplets

The Kerr effect on vesicle-like droplets is described. We give a simple derivation of the Kerr constant for a dielectric fluid droplet immersed in another fluid, assuming that the droplet in an electric field becomes a prolate ellipsoid. The Kerr constant is evaluated also for a droplet covered by a membrane of finite thickness. The latter result differs significantly from the result by E. van der Linden et al. [Physica A 156}, 130 (1989)]. Due to the difference the bending rigidity constant of the surface layer extracted from their experiments on droplet microemulsions should be increased about two times.