@dalehileman,
Given your age. Am I right to suspect that you are taking some form of medications? Also, when do these "blind spots" occur?
The eyes are a very interesting part of the human body. The blind spots you described seem similar in ways to sun spots. It could be from your computer screen. The medication ties into the dehydration aspect of the eyes. If your body does not have enough water, the eyes are typically one of the first points that get sacrificed for parts of the body that are more necessary in the survival of the body as a whole.
If my assessment is correct, more water should stop the spots from occurring. However, if you wanted to take safeguarding the health of your eyes further, I'd recommend a pair of sunglasses that will prevent more direct light from affecting your eyes, while not impairing your ability to see what you need. You can also decrease the brightness of your monitor screen.