In this issue, van Norren and van de Kraats1 propose a novel means for comparisons of different IOLs with regard to short-wavelength spectral properties. (see pages 1374–5) They have developed the concept of defining an equivalent age for comparing the spectral properties of any IOL with those properties of the ageing natural crystalline lens, which they term a “virtual age.” Recognising the need to balance short-wavelength protection with visual performance in the blue-violet, they have defined two “virtual ages,” one for “photoprotection” and one for “photoreception.” Of course, the reference age is based upon properties of northern European lenses, but the concept allows the ophthalmologist and patient an understandable means for comparison.

Arguments …