I have high-power eyeglasses (about -10 diopters in one eye, and -12 in the other). I have always been bothered by the chromatic abberation--- almost any visual object (reading text, reading music, street signs, traffic lights, etc) is clear only in the center of my lens, and gets increasingly blurry as one gets away from the center. I've had my lenses always made from a higher-index plastic.. not the standard cheap plastic. Usually I ask for 1.56. This makes the lenses thinner and lighter. However it has been my observation that higher index plastic has more chromatic aberration than lower index I was reading the Wikipedia article on "corrective lenses" (The forum won't let me link to it, but you can find it easily) It appears that the chromatic aberration depends on something they call the ABBE value. This gets me wondering, is there a way I could get lenses that are both thinner and have less chromatic aberration, by choosing a plastic with a high ABBE value (high is good)? For instance, in the chart in that article, I see that the material I usually use, 1.56 plastic, has a low ABBE value (bad), while an even higher index material (1.60) has a higher ABBE value. The question is, does the amount of distortion depend only on the ABBE value, or does it also depend on the refractive index at the same time? Can I predict that going to 1.60 plastic will increase/decrease the amount of distortion? Or does it depend on other factors, like lens power, base curve, optical center position, lens coatings, etc? I can't use contacts because I have prism in my lenses (2 diopters inward in each lens, and 1 diopter up/down skew). Also I have chronic eye irritation from Grave's disease so I can't tolerate putting anything in my eye.