[JP (OP)]

I'm not a morning person at all.  I'm not much use until I have my morning  coffee or tea.  However, when my schedule requires it, I sometimes go running in the morning.  I've noticed that when I do so, I get a slight flickering in the center of my vision in both eyes.  It seems kind of like  the flickering you can see from a fluorescent light that's going bad.  It's hardly noticeable with my eyes open, but it's quite distinct if I close my eyes.  I've never had this effect when running at other times of day, or on mornings when I don't exercise.  I'm not particularly worried about it, but I'm curious what might cause it.  Any ideas?

[RD]

Possibly low blood sugar (hypoglycemia) if this only occurs on your morning run: insufficient carbohydrate in your breakfast to fuel a run.

[Chemistry4me]

Yes, I have noticed this after an intense bike ride in the morning.