Test yourself with the help of the Amsler Grid !
In my case it was Severe Optic Neuritis. The Amsler Grid was the first tool I turned to in the quest to help identify my symptoms.
If you are experiencing sudden blurriness unrelated to an eye injury, visit an Ophthamologist, immediately! They may refer you to a Retina Specialist for further diagnosis and treatment.
For more information about eye care, eye diseases and the care and feeding of the eye check out all about vision.com and their page on supplements for the eye.
Take care of your eyes!