This is a rather unique slide rule was specially commissioned by a German Dr. Reiner for patients suffering from presbyopia (inability to focus on nearby objects) to easy calculate the correction needed. It also has a specific table on the back. It comes as a full set with instructions and outer box as well as the leather case (not signed). It was probably a late production, guesstimating ca, 1975. The slide rule and cursor are made of plastic and everything is in near mint condition. Do also check out the color vision test by Aristo model nr 10 046. This pocket slide rule measures 15 cm or 6 inches long. Check the attached video on how to work your vintage man tool: slide rule operation instructions!
