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
Pupillary Distance. 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. PD, or pupillary distance, refers to the distance in millimeters between the center of one pupil to the center of the other. Having a correct PD on your glasses prescription insures that you are looking through the ideal spot in your lenses.