Does "at optical infinity" mean "as an optical option"?

Context:
Dawkins provides an interesting account of the origin of religion. He began by explaining why, for example, moths fly into the candle flame, which seems like suicide (p.201). Dawkins argues that before human beings invented artificial light, the only available sources of illumination in the night scene were the moon and the stars. At optical infinity, these celestial objects are suitable for insects to use as compasses.