How would i know if i have a detached retina?

Vision loss, floater: The classic symptoms of retinal detachment are a large number of floaters and sparks in front of one or both of the eyes, as well as sudden and painless vision loss. If you are experiencing any or all of these symptoms, see an eye doctor immediately. There is a better chance of regaining your sight if it is treated within 2 days of onset.

See EyeMD: Common symptoms associated with rd are floaters, flashing lights, loss of peripheral vision, and decreased vision. It is possible to have an asymptomatic rd. The best way to be sure is to see in ophthalmologist and have a dilated exam done.