Reference photo shot with a Nikon D3200.
Model: Isaac I.
Step by-step guide
The key to great realism in prismacolor is to add lots of layers. Start light to prevent premature wax buildup. 
Finished piece.
(Drawing in Prismacolor pencils, Archival ink .005, white ink gel, and blending tortillons on toned tan paper).
Isaacs Eyes
Published:

Isaacs Eyes

Drawing created on 5.10.15.

Published:

Creative Fields