This article explains eye shine and coat types.
Eye Shine My guess is it shows up differently because of lighting and flash. To have it work the best, you should be in a fairly dark room with very little additional lighting and use a flash. The other possibilty is your dog may have a mixed coat, you know a blend of cotton and silk. I don't think that's the proper word, but I just can't think of it right now. Darn getting old is a bitch!