depends on the situation. it still retains the energy, but if the shards are really teeny tiny i wouldn't use it for practicality reasons [unless you're placing them in a jar or something]
if you were already using the tigers eye in a spell and it broke randomly, it could be considered a sign. or if you were upset and broke it for whatever reason you might of undone the spell and perhaps see some negative repercussions.
all crystals/stones are broken into smaller pieces, shaped, and/or polished but they still retain their energy. i would cleanse the pieces if you intend to use them, but otherwise they're fine.