Hi... Are you a diabetic/hypertensive? Is there any visual problem did you notice or was observed during the examination? There can be rupture of blood vessels causing sudden drop of vision most commonly in hypertensives or diabetics.. What you are having could have been a chronic one which might have not caused any visual loss and doesn t need active intervention now... Suggested physician consultation could be to diagnose any hypertension or any other metabolic disorders.. If you can give other details, I can say if it requires any active intervention.. Take care.. Will be available for further queries...