Photonic devices are impacting medical care and research along two fundamental tracks. One provides clinicians with tools to improve outcomes. The other gives researchers the means to probe more deeply into critical life functions. Optogenetics is a case in point. It has transformed brain research by rendering individual neurons sensitive to light. Now a number of scientists are applying this experimental precision to the study of the heart. As our cover story by Contributing Editor Marie Freebody points out, cardiac optogenetics faces serious obstacles, not the least of which is that gene transfer of light-sensitive proteins to the heart can trigger an immune response. But the promise the method holds out is great: Cardiac optogenetics someday may have the capacity to halt life-threatening arrhythmias and to enable patient-specific drug therapies. “Cardiac Optogenetics Seeks to Fulfill Its Promise” takes a close look at a research field still in its infancy (read article). This issue also contains a story by Sead Doric, president of Doric Lenses. Doric became involved in optogenetics at its earliest stages when Karl Deisseroth, the Stanford neuroscientist who created the technique, sought a fiber optic rotary joint for his experiments. Doric compares two prevalent methods for optically monitoring neural activity in freely moving animals — fiber photometry and head-mounted fluorescence microscopy. He also discusses some of the hardware that makes the research possible. “Making the Connection: Optics, Neural Activity and Behavior” (read article). The development of optogenetics helped spur the creation of the BRAIN Initiative, the public-private partnership committed to improving the treatment and prevention of brain disorders. This month’s Biopinion, by Yama Akbari, a board-certified neurologist as well as an assistant professor and researcher at UC Irvine, discusses the potential of photonics to improve outcomes for critical care neurology patients. Noninvasive photonic monitors of brain activity, he writes, could allow for diagnosis by paramedics during the critical first few minutes and hours following an injury. Once a patient is hospitalized, they could provide the means for continuous brain monitoring. “Photonics can change critical care neurology” (read article). Elsewhere in the magazine: • Peter Behringer of Basler AG writes about medical applications of embedded vision. Already in use in industrial settings, the combination of board-level cameras and miniaturized processing units is moving into dermatology, ophthalmology, in vitro diagnostics, microscopy and laboratory automation. And it opens the way for such improvements as image-guided diagnoses and nearly instantaneous access to second opinions. “Embedded Vision Moves Into the Clinical Realm” (read article). • Celine Canal and Andreas Kohl of Quantel Laser outline another advancement that is enabling more portable medical devices: the use of pulsed laser diodes for photoacoustic imaging. The resulting compact devices, they write, can simplify workflows, reduce costs and increase accessibility to patients under home care or in low-resource settings. Applications of diode-based photoacoustic imaging include oncology, rheumatology and the diagnosis of cardiovascular disease. “Pulsed Laser Diodes Can Hasten Clinical Use of Photoacoustic Imaging” (read article). • Finally, in this month’s special section on OCT, Senior Editor Justine Murphy covers questions about the technology’s future (read article). Enjoy the issue.