The retina, which lines the inner back wall of the eyes, is the portion of the eye which collects light and transmits the light messages to the optic nerve and brain. When the retina separates from the back wall, it is known as retinal detachment. It is considered a true eye emergency. If left untreated, it will cause permanent damage and vision loss. Symptoms that could indicate a retinal detachment include, a sudden onset of flashes of light that could resemble lightning and a sudden appearance of floaters not seen before.