First remove the old sleep eyes. Take off the doll's head and slice the back of the eye socket using a small scissors or exacto blade. Try not to do too much cutting, no more than necessary. Take out the eyeball or push from the front to push it into the head.

Sometimes I can put the new eye in the doll's head by maneuvering it with my fingers but sometimes it is very awkward or perhaps the doll is too small, the neck is too narrow. Then I use a small doll sock to help get the new eyeball in place. I use small cheap tube socks for dolls, they are almost as thin as nylon and they are small tubes for doll feet. I suppose you could rig something similar using nylon stocking material. I put the eye in the tube sock and then put it inside the doll's head. Use a tweezers to grab the sock and pull the eyeball into the socket. The tube sock makes it easy to pull the eye into place.

Arrange the vinyl flaps of the eye socket in back. Then cut off as much of the sock as you can (from the front) and work the rest of it out by pulling on it from the front with the tweezers. You may want to snip the foot of the sock from the back in order to pull it out the front.

I turn the eye into position using a crochet hook (for yarn not thread) so it's not a sharp one but it seems to work for turning the eye. I also use a very small flat blade screwdriver to adjust the eye position.

It is very important to adjust the eyeballs so they look natural: not crosseyed or cockeyed.

Then apply glue compound to the back of the eye socket to seal it shut. I use the Liquid Nails glue from Home Depot: you can buy it in a toothpaste style tube or caulking tube so I buy the small tube. It's thick like putty and adheres very well to vinyl so it forms a tight cap across the back of the eyeball. I use a popsicle stick or plastic spoon handle to apply the Liquid Nails putty, or if there is enough room inside the head then I wear a disposable glove and spread the glue with my fingers. Leave the head face down overnight so the glue putty can dry.

To clean up your hands afterward and get the glue off, use a solvent of some kind. Paint thinner is good.

Where to I get sleep eyes for replacements? I get the eyes from dolls that are no good but do have decent eyes. I'm always harvesting eyeballs to transplant into other, better dolls. As with humans, it requires the sacrifice of one doll in order to salvage the eyes of another.