My vision is 20/70, I need glasses, have myopia and a mild astigmatism. Should I get plastic or polycarbonate lenses? Which is better?
If you ask which is better, then plastic is better. When optical professionals look at visual acuity through a lens material, we use what is called an Abby Value. The lower the Abby value, the more chromatic aberration there is to the lens which is a rainbow effect on the edges but which presents itself as blurriness. Polycarbonate has the lowest Abby value of any material - 29. Glass has the highest (but I would never recommend glass). Plastic is just below that, followed by a material called Trivex. Many opticians call polycarbonate polycrap. That's what it really is. However, if you need a thinner, lighter lens as determined by your actual prescription, which you did not give us, then, Trivex or a 1.60 Hi Index material are available. Besides lens materials, the shape, size and width of the frame influences the thickness of the lens. That is why it is imperative to have an Eye Care Professional like an optician help you pick out the frame that is best suited to your prescription. Individuals outside the industry have no idea what to get because they are not versed in the science of optics. Hope this helped.
