Hi, The flash of light may be a sign of migraine
aura or due to any problem in the retina. Since it is recurring and now diagnosed as diabetic you need further retinal evaluation using retinoscopy
and also other systems. You can contact any doctor for initial evaluation in your area as urgent basis to diagnose the problem.
You have mentioned 147, is it fasting or random sample
(after food). You are required to manage diabetes
using lifestyle modifications and with diet based on your sugar levels.
Hope this helps you.