From Andrew Field
Your interview highlights the excellent invention of adaptive spectacles by Joshua Silver (20 August, p 48). However, it seems to miss the point that the spectacles would make excellent and rapid sight-testing equipment rather than being an end product to replace spectacles. Anyone with just a little knowledge could use the adaptive optics to speedily test hundreds of people’s eyes.
Cheap, mass-produced plastic spectacles could then be taken off the shelf to match each person’s prescription. Mass-produced spectacles would be physically stronger and considerably cheaper to produce, whereas the membrane of the adaptive spectacles has to be quite thin to be flexible, and would always be a weak point if used for normal daily wear.
Woodbridge, Suffolk, UK
