Drug delivery device

A syringe-like device having a chamber in which a pressurizing piston reciprocates. The chamber is connected on one end to a vial containing a drug to be delivered to an eye and on the other end to a needle or cannula for administering the drug to an eye. Pulling proximally backwards on the piston creates a vacuum in the chamber and draws the drug out of the vial. Upon release of the piston, a spring pushes the piston forward, pressurizing the chamber. Delivery of the drug is controlled by a roller pinching off a section of compliant tubing between the chamber and the cannula, with a design similar to a peristaltic pump. A one-way valve prevents the drug from being expelled back into the vial. The flow rate of the drug out of the cannula can be controlled by rotation of the roller.