Submitted by examrobotsa on Thu, 01/01/1970 - 05:30 When an optician prescribes a-5D lens, what does it mean?Concave lens of 20 cm focal length Convex lens of 20 cm focal lengthConcave lens of 5 cm focal lengthConvex lens of 5 cm focal lengthstats: 0,328,328,328,168,120,40