intersection of two lines one of which is normal to the external lens surface at the point where it is desired that the normals to the modified and unmodified surfaces are to begin to diverge the other of which is the normal to the modified surface where the modified surface joins the obstruction in both internal and external modification embodiments the normals adjacent to the obstruction are calculated by application of the law of refraction with respect to the desired degree of refraction to negate the obscuration of rays by the obstruction in fig8 the internal surface 43 has a radius r 1 the external surface 44 has a radius r 2 and the modified surface 24 has a radius r 3 the origin 58 of the radius r 3 is offset a distance 60 from point 36 of the light source in a best mode of carrying out the invention r 1 0 681 r 2 0 776 r 3 0 577 and distance 60 0 103 fig9 shows the light source 36 right lens segment 18 and left lens segment 20 having modified surfaces 24 and 26 joined at 22 a a lens divider junction which employs an opaque vertical shield that extends radially outward from the assembly and b a lens segment junction which is caused when two lens segments are physically joined together a region is created on both sides of the junction where the bonding agent or process chemical ultrasonic etc results in the inability of this.