Many patients believe that doctors take an oath to, “First, do no harm.” Primum non nocere is the Latin translation for this imperative. It’s a comforting thought, but there is no such requirement for physicians — not even in the Hippocratic Oath. Instead, this oath demands that those who take it should follow a “system of regimen … for the benefit of my patients” and “abstain from whatever is deleterious and mischievous,” according to Dr. Robert H. Shmerling, the faculty editor of Harvard Health Publications. Even though doctors are not bound to the requirement to do no harm, they should generally aim to inflict as little of it as possible, given the patient’s condition and circumstances. And this issue of BioPhotonics highlights how photonics are stepping in to help ophthalmologists to do just that. For example, my cover story (read article), “OCT Angiography Opens Eyes,” details how the first wave of FDA-approved optical coherence tomography angiography (OCT-A) devices are making their way into the offices of U.S. ophthalmologists. These devices are allowing them to noninvasively look for ocular vasculature features that could be indicative of retinal disease. While ophthalmologists have been able to similarly check for retinal disease by using fluorescein angiography and indocyanine-green angiography, these methods rely on the injection of dyes, which can leave patients, who are mostly elderly, nauseous and anxious. That is not the case with OCT-A. In “New Quantum Dots Excite In Vivo Imaging Advancements,” (read article), Glenn J. Bastiaans, of NanoOptical Materials, similarly reviews the toxicity concerns posed by cadmium- and lead-based quantum dots (QDs) and the promise heavy-metal-free QDs hold for in vivo imaging. Other articles you will not want to miss include: • “High-Content Screening Goes Beyond Fluorescent Pictures,” by Kris Ver Donck, of Confluence Consulting BVBA, (read article); and • “Neuroscience Driving Continued Growth in Multiphoton Microscopy,” by Marco Arrigoni and Darryl McCoy, of Coherent Inc., (read article). I hope you enjoy this month’s issue of BioPhotonics. Be sure to visit Photonics Media’s Editorial Channel at www.photonics.com/VideoGallery to view a fun video based on my Postscripts article at the end of the magazine. Watch how lasers are being used to zap mosquitoes. If these pests are ruining your summer, you’ll get some satisfaction out of it.