Early 20th century eye surgery tool with its carrying case, for use by ophthalmologists. Ophthalmology is the study of the eye and its disorders and their treatment. This instrument, known as an erisiphake, dates from the 1930s. Invented by the US ophthalmologist Theodore J. Dimitry, this device is used to remove cataracts from the eye. This one was produced by the V. Mueller company of Chicago, USA, and worked on a vacuum principle. The instructions are included at upper right.