Set of slides for use with a Worth amblyoscope, c 1890-1910.
© Science Museum / Science & Society Picture Library
An amblyoscope is used to train an eye to share equally in the task of binocular vision, instead of one eye doing the bulk of the work. Amblyopia is the name for the condition where one eye is 'lazy', forcing the other to work harder. Manufactured by Clement Clarke Ltd, England.