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
The optical center of your eyeglass lenses is the part that gives you the truest vision, and it should be directly in front of your pupils. To determine how to place the lenses in your frames so the optical center is customized for your eyes, the eyeglasses lab needs to know the distance between your pupils, or PD. It can be tricky to measure your own PD, somewhat akin to trying to cut your own hair.