Treating many of the diseases that cause blindness involves frequent, painful injections directly into the eyes, putting patients at risk for infection, cataracts, and torn retinas. Ellis Meng, an assistant professor of biomedical and electrical engineering, has built an implantable pump to deliver medications more safely.

About the size of a watch battery, her device uses a microfluidic pump to push medications from a reservoir through a small tube and into the eye. A surgeon implants the pump and reservoir on the outer surface of the eye; only the tube enters the eye itself. And unlike existing implants that must be replaced periodically as they run out of drugs, Meng's is refillable. Instead of weekly injections or monthly surgeries, a patient could take just one trip to the operating room, dramatically reducing both pain and risk. Meng is still testing the eye pump in animals but hopes it can be tested in humans within five years. --Jocelyn Rice

Prescription pump: Ellis Meng's implantable device for delivering drugs to the eye consists of a chamber that stores the medication; a pump; and a tiny tube that enters the eye. Within the pump, wirelessly powered platinum electrodes produce a current that splits water into hydrogen and oxygen gas, inflating a miniature bellows to force medication out of the reservoir, through the tube, and into the eye.

1. Implantable drug pump

2. Delivery tube

3. Refill port

4. Drug reservoir

5. Polymer bellows

6. Pump base and electrodes

Credit: Bryan Christie Design