Eye pearls are a lucrative but painful business.
Much like oysters, human eyeballs can grow pearls when given a small pebble or other solid irritant. The eye coats the irritant in a protective glaze that becomes a pearl like the one seen above. Valued at 50 times that of common pearls, eye pearls were highly sought in ancient times. The phrase “A twinkle in ones eye” derives from this practice, twinkus being latin for pearl.
Eye pearls are illegal now, as centuries of eye slavery was surely one of the most painful epochs of ancient times. But still, some intrepid and often masochistic individuals use their own eyes to grow this strange cash crop.