Devices and devices for the treatment of the eye are disclosed. Preferred devices of the invention include a piercing member that is inserted into the eye to create a pathway for a cannula. The cannula is slidably mounted to the piercing member and is adapted to reach a treatment site within the eye at which material is injected into and/or withdrawn from the eye. The outer diameter of the piercing member is small enough to allow for self-sealing of the insertion site of the device upon the device's withdrawal therefrom. Also disclosed are methods for the utilizing the devices to treat the eye.