Yes, it's true, more Optics on easter. This one is harder. It has to do with spectacle magnification. A 6.00 D increase in front surface curvature of a +4.00 D lens with 5 mm thickness and index 1.523 will increase the percent magnification of the total lens by what amount if the central thickness is assumed to be kept constant and the distance from the spectacle plane to the entrance pupil of the eye is 17 mm? The answer is supposed to be 2.17 % So I used the formula M=[1/1-t/n F1][1/1-hFv] for two lenses Lens 1: Fv=+4 F1=x n=1.523, h=17 mm, t=1 Lens 2: Fv=+4 f1=X+6 n=1.523, h=17 mm, t=1 I tried to calculate this out to get magnification for each of the two lenses and calculate the % mag from there but I get 1.67% no matter how many times I do it. ARRGH. Wherein lies my ineptitude? Thanks, Eyegirl.