You need to specify if it is white spots in your vision or white spots on ophthalmic examination. If you see white spots in your vision it could be related to migraine if you have headche. If you felt tingling numbness or difficulty of speech it sould be a transient ischemic attack.

I am assuming he is mentioning about "cotton wool" spots. When you have uncontrolled diabetes you develop what is called diabetic retinopathy which is basically due to damage to the blood vessels that supply the part of the eye that captures vision(called as retina).

There are two types of damage:Both can occur without symptoms, like in your case.

1.Proliferative retinopathy: abnormal blood vessels proliferate and over a period of time causes damage to normal parts. there are 4 stages in terms of severity. If it's upto stage 3 u don't need laser treatment.
2. Macular edema: causes blurring of vision. You need laser treatment if macula is involved.

In either case you need eye examination once a year and tight control of your blood sugar. Also if your eyes are getting retinopathy, it's time to check your urine albumin because you are at high risk of nephropathy which means your kidney cells might be starting to get damaged too. For that you need to do a Spot albumin/cr ratio and if it is increased you might need treatment for that.