Complex sentence: Led by shapeshifter Mr. Barron (Samuel L. Jackson), they hunt Peculiars to consume their eyeballs enough to became milky-white eyed visible Peculiars known as "Wights".
Split into simpler sentences: Led by shapeshifter Mr. Barron (Samuel L. Jackson), they hunt Peculiars to consume their eyeballs. When enough eyeballs are consumed they Hollows can tansform into milky-white eyed visible Peculiars known as "Wights".