A popular superstition that a squint was a bad omen. It was
said that if you met a squint-eyed person, you should spit three
times, to avert bad fortune. The superstition is an old one, and
it was referred to in the treatise on Fascination (de Fascino) published
in 1589 by Vairus, prior to the Benedictine Convent of
St. Sophia in Benevento, Italy. In this work he stated Let no
servant ever hire himself to a squinting master.