A needle with a ring round it, so that it can only be pushed a specific distance into the body.
A surgical needle with a shank that has a protruding collar to stop it when the needle has been pushed a prescribed distance into the tissue. A stop needle has the eye at the tip.
A needle with an eye at its tip, with a flange or shelf extending out from its shank end that prevents the needle from being inserted farther than the shelf.