I have read your question ,
This is a common experience most people feel , but it again depends on various reasons , in your case
I think it was due to sudden jerk or bending ,there is nothing to worry much , vision blurring and buzzing sound are common symptoms for hypoglycemia
or fasting or malnutrition
, hyper tension etc.
I recommend you to take good nutritive food green veggies ,low fat food , and milk.
But if the problem persists Suggest you to consult a physician nearby fo further medication.
I hope this was informational and useful,
Wishing you a good health,