But new Johns Hopkins research in mice suggests that neural stem cells, the bodyâs source of new brain cells, are resistant to radiation, and can be roused from a hibernation-like state to reproduce and generate new cells able to migrate, replace injured cells and potentially restore lost function.
Pupillary Distance (PD) You'll need to know your PD if you want to order glasses from EyeBuyDirect. Don't worry if your glasses prescription doesn't include your PD, we can show you how to measure it by yourself. How to measure your pd
Janean Nichole Beri asks, âwhat is PD and is it important?â Well Janean, thanks for the great question! PD means âpupillary distance,â which is the distance between the center of each pupil. This is needed to make a pair of Rx glasses, because it tells the manufacturer of the glasses where to put the optical center on each lens.