level on the retina which does not include contrasted glare patterns as hereinbefore discussed a discussion of random scattering is useful in understanding the present invention a random scattering surface can be modeled at the surface with uniform scattering in all directions in an ideal case such as a lambertian scattering surface shown in fig6 fig6 shows an illustration of the probability distribution of such a scattering model however a practical surface usually is more accurately modeled as a surface that scatters light in gaussian distribution relative to the spectacular ray which is either the reflective ray or transmitted ray fig6 also gives the probability curve for gaussian scattering distribution when the distribution width sigma is very large that is gt 1 the surface is close to a uniform scattering surface whereas when the distribution width sigma is very narrow lt 0 1 the surface is close to an optical surface the distribution amplitude represents a scattering level at a specific scattering direction it is the ratio of all energy associated to the scattered rays to the total energy associated to all reflected or transmitted rays the larger the scattering level the more energy associated with the scattering ray the intraocular lens 10 and the surface roughness or frosting 24 provided thereon is fabricated by providing a blank lens preferably silicone having the center lens portion 12 and surrounding lens portion 14 and thereafter roughening the surrounding lens portion 14 by electrical discharge machining utilizing apparatus 60 diagramed.