Yes this is a potentially serious problem, especially given your history of vein occlusion. You need to see your eye MD ophthalmologist. And here's some good advice: when you have a problem tell the MD when you come in. Physicians are not mind readers and if you fail to disclose problems they may not show up without special tests or attention.
Thank you for your prompt reply John, I appreciate your advice and I shall be seeing my doctor as soon as possible.
Best of luck It does not necessarily mean its serious but it does mean its a symptom that has to be seriously evaluated before saying "don't worry".
Saw my GP, got refered to specialist in TIA ,she gave me ultra sound test which was ok, ECG which was ok, came to the conclusion that it was a very small blood clot passing through one of the veins and causing a TIA or mini stroke. I am on asprin now for a couple of weeks and have to get the results of blood tests and re-visit my GP. Thanks once again for your advice and help.Not so worried now!
So if necessary make some serious life changes. TIA/mini-strokes are mother nature's of warning you about a major stroke or death. You know the drill don't be over-weight, don't smoke, don't drink over 1-2/day (if you must drink and if you do choose red wine), control your blook pressure and blood fats (cholesterol/triglycerides), exercise, eat a great diet mainly fruits, vegetables and consider dropping red meat.