I wouldn't think so. They were originally devised to compensate for the loss of vision in the right eye if a right handed shooter, and have been around a long time

Heinrich Ebert, Wien/Vienna, c. 1820-1837



"The Breech-loader and How To Use It" 1892 by William Wellington Greener



More recent devices

Carey Sidesighter



I found this on an English website, but no name or maker; possibly home made. Any of our British correspondents aware of the maker?




https://sites.google.com/a/damascusknowledge.com/www/home