Optical isomers are compounds that have the same molecular formula, same structural formula but different spatial arrangements of atoms in space such that they are non-super-imposable mirror images of each other.
For optical activity, a compound must contain a chiral Carbon atom.
A chiral Carbon that is attached to four different atoms or groups of atoms is called chiral Carbon.
Glucose has a molecular formula
In glucose, there are four chiral Carbon atoms.
The total number of optical isomers of any compound is , where, is the number of chiral Carbon atoms.
Therefore, the total number of optical isomers of Glucose is
Hence, there is a total of 16 optical isomers of Glucose.