What is the difference between E-Z isomers and optical isomers?

E-Z isomers (aka geometric or cis-trans isomers) and optical isomers are both examples of stereoisomers, two or more compounds with the same structural formula but with bonds that are arranged differently in space. E-Z isomers have different substitutes at each end of their double bond. As the double bond cannot rotate the substituents are locked in place. For example E - 1,2 dibromoethene and Z- 1,2 dibromoethene differ in the placement of the hydrogen and bromine atoms. Optical isomers (aka enantiomers) are molecules that are mirror images of each other that are non identical and cannot be superimposed.