Epimers and anomers are both optical isomers that differ in the configuration at a single carbon atom but there is a difference in their definitions.
Epimers
Epimers are optical isomers that differ in the configuration of a single carbon atom
For example D-galactose and D-mannose are epimers of D-glucose.
(from biochemnoob.wordpress.com)
D-Galactose is an epimer of D-glucose because the two sugars differ only in the configuration at ##C-4##.
D-Mannose is an epimer of D-glucose because the two sugars differ only in the configuration at ##C-2##.
Anomers
When a molecule such as glucose converts to a cyclic form it generates a new chiral centre at ##C-1##.
(from www.chem.ucalgary.ca
The carbon atom that generates the new chiral centre (##C-1##) is called the anomeric carbon.
Anomers are special cases they are epimers that differ in configuration only at the anomeric carbon.
For example -D-glucose and -D-glucose are anomers.
(from wikispaces.psu.edu
The form has the anomeric ##OH## group at ##C-1## on the opposite side of the ring from the ##CH_2OH## group at ##C-5##.
The form has the anomeric ##OH## group on the same side as the ##CH_2OH##.
In D-fructose the carbonyl group is at ##C-2##.
(fromweb.pdx.edu)
Here ##C-2## is the anomeric carbon.
(from science.uvu.edu
-D-Fructofuranose and -D-fructofuranose are anomers.