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
Your PD is the distance between your eyes, measured between the centre of your pupils. For a pair of glasses to perform as well as possible for you, the lenses need to be made to match this distance between your eyes, so that the centre of each lens aligns with the centre of your pupils. This is important if you have a high-strength prescription or require varifocals for example.