Early 20th century eye surgery tools and carrying case for use by ophthalmologists. Ophthalmology is the study of the eye and its disorders and their treatment. These tools are used for cautery and electrolysis of the eye. They used electric currents to apply heat to cut through tissue during surgery to minimise blood loss. The wires were attached to the device at lower right, and the tip at upper left was used to make the incisions. Dating from 1920, this kit was made by the Keystone Electric company, based in Philadelphia in the USA.