A retinal vein thrombosis and a retinal artery occlusion occur because of the same mechanisms that cause ischemic or hemorrhagic strokes in the brain. They just have different names. The former can be though of as "strokes in the eye".
JCH MD
Hello my mum has the same probem, can you please tell me if this is a stroke,
the Dr said it is from smoking,
From this discription she most likely has a retinal vein thrombosis or a retinal artery occlusion (most likely the former). This is often due to disease like high blood pressure, high choleserol, diabetes, smoking, "thick blood", etc. that's why she needed to see her MD.
The prognosis depends on the amount of damage, where the damage is, the exact diagnosis. Only time will tell. Important to start working on protecting the other eye.
JCH III MD