Phoropter (for eye testing)
This Phoropter, a device that measures binocularity, was invented by Henry DeZeng. In fact DeZeng was the man who also created the word Phoropter. He coined the word to describe his latest phoro-optometer device and trademarked the name.
DeZeng’s business was acquired by American Optical and they continued to use the word to describe all vision testers and the word has now become genericized.