New method to detect ultrasound with light
A tiny, transparent device that fits into a contact lens can determine the speed of blood flow and oxygen metabolic rate at the back of the eye, helping to diagnose diseases such as macular degeneration.

Developed by Northwestern University scientists, the device, called the Micro-ring resonator detector, can determine the speed of the blood flow and the oxygen metabolic rate at the back of the eye. This information could help diagnose such common and debilitating diseases as macular degeneration and diabetes.

The Micro-ring device builds upon Professor Hao F. Zhang's groundbreaking work in 2006 to develop photoacoustic imaging, which combines sound and light waves to create images of biological materials. The imaging technique is being widely explored for both fundamental biological investigations and clinical diagnosis, from nanoscopic cellular imaging to human breast cancer screening.