What a broad question. What kind of eyes on what kind of streamer? On the Edison Tiger they are just tied in! However I doubt that is what you are meaning. If you are putting a large head on them with epoxy or UV resin then put the eyes on and coat as you build the head. If you want dumbbell eyes that will not twist around the shank mix a little silica sand in with some epoxy and coat the wraps after tying in.

Something I do quite a lot is unbalance the head by putting a thicker coat of UV over one eye. The idea is to make the fly wiggle more when pulled through the water. See my Bend Back Sand Eel FOTW October 7th

One trick you may find useful is if you are coating the stick on eyes make one turn of white thread over them to secure them in place while the coating dries. The thread will disappear under the coating but stop them slipping while drying.

Hope I've covered your question. More details will help.

Cheers,
A.