From Science Museum London & Wellcome Images Collection:

Votive offerings were presented to a god, either in the hope of a cure or as thanks for one. They were made in the shape of the afflicted body part – in this case a person’s ears. They may have been experiencing deafness or infection. Made from bronze, the ears are now coated with chemical compounds formed from corrosion (called bronze disease), which gives them their green appearance. The use of bronze may indicate a wealthy owner as most votives were made from terracotta.