¹ Source: wiktionary.com
Medical Definition of Optical isomers
1. Isomers differing only in the spatial arrangement of groups around a central atom. Optical isomers rotate the plane of polarized light in different directions. For all biological molecules in which the possibility of optical isomerism exists, only one of the isomers is functional. This entry appears with permission from the Dictionary of Cell and Molecular Biology (11 Mar 2008)