Hydraulic chair and column, with stool, accessories include Green's refractor, by Bausch and Lomb of USA, c. 1930

You might have seen something like this had you visited an opticians or ophthalmologist in the 1920s. The hydraulic chair was made by optical instrument manufacturer Bausch and Lomb. It includes accessories for use during an eye examination. These include an ophthalmoscope for looking inside the eye and a retinoscope for shining light into the patient’s inner eye to assess the light sensitive surface called the retina. It also has a refractor. This optical instrument helps determine whether spectacles are required.