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
Beginning at around age 40, you'll find that the usual glasses or contacts you always wore will not correct focusing problems caused by presbyopia. The amount of nearsightedness you have determines how close or far you need to hold an item to see it clearly without your glasses on. If you are mildly nearsighted (with a prescription of -1.50 or -2.00 D, for example) you will see very well at a normal reading distance of 14 to 16 inches from your face.