The invention provides devices useful for the deliver of active agents to the eye in a controlled manner. In the devices of the invention, the active agent is present within the device in a continuous or discontinuous concentration gradient.本發明揭露一種用於控制方式傳送活性劑予眼部之裝置。在本發明之裝置中,存在裝置內之活性劑的濃度梯度係連續性或不連續性。