People can feel affection for others even if they don’t necessarily find them that visually attractive. It could be argued that someone’s looks are a less good indicator of their suitability as a mate than one’s internal feeling about them. These may not be conscious, but are roughly indicated by the degree to which one’s pupils automatically widen when seeing them.
When you look at a nearby object, using multifocal lenses, your pupils widen and that allows light to pass through a larger number of long-focal-length rings of concentric lens material…and vice versa.
Today’s invention is a contact lens which allows the wearer to inspect a large number of photographs of potential mates. The viewing distance is set so that wide pupils will allow the image to appear in perfect focus, thus showing that the image is of one to whom the wearer is strongly attracted emotionally.