I think it is depending on what type of worm eggs. I am not really an expert in worms but I know now that for roundworms, you can see the eggs in the stool and also some segments for tapeworms. As for whipworm and hookworm, they can only be seen under the microscope.
I have seen 1 dead roundworm when I poke through his stool few days ago(not with my fingers of course, with a Q-tip). Its white about 1-2 inch and pointed on the ends. As for eggs, I see some white dots which are smaller and some white ones that look like sesame seeds. Its gross. If you go to the link I attach below and look at the roundworm picture, the eggs in the stool are the small white dots I see in his poop.
http://www.thepetcenter.com/exa/worms.html
The thing is, I have been using Advantage Multi 10 which supposed to be prevention for roundworms as well but it is applied in between his shoulder blades. Apparently, in this case it is not good enough.
He poop 3 times this morning and it still contain white dot eggs (no more sesame type) and the poop is small quantity and mucus like. I know I have been so worried about it because although he is not my first dog, its my first time dealing with worms and they do scare me!!!