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
However, some eye doctors know that if a customer asks for the PD, they are ordering their glasses online, and savings hundreds of dollars from the huge markups from local optical retailers. If the eye dr. has a relationship with a local optical retailer, they may be reluctant to give their customer the PD, which would take business away from the local optician. I must stress, Janean, that guessing at the PD number is not the way to go. If the PD isnât accurate, you wouldnât be able to see well with the glasses, and you may feel one eye being âpulledâ away from the optical center on the lens. A PD must be measured accurately for the glasses to be accurate.