The retina is a nerve layer lining the back of the eye that senses light and color. The retina then sends these signals to the brain and plays an important role in vision. The retina functions like the film in a camera, taking the picture, and allowing you to see.
The retina normally sets flat on the back of the eye, much like wallpaper on a wall. When the retina detaches, it separates from the eye wall. The early symptoms you experience are a sudden increase in floaters or flashes of light. A curtain or shadow in your vision, central or peripheral is a late symptom. You should schedule an immediate appointment if you notice or experience any of these symptoms.