The most common cause of retinal detachment is a tear in the retina due to injury or disease. A buildup of tissue between the retina and the vitreous gel and fluid buildup beneath the retina can also cause retinal detachment, according to WebMD.
Symptoms of a retinal tear include floaters in the field of vision and flashes of sparks or light when moving the eyes or head, notes WebMD. The flashes of light, which typically appear at the edge of a person's field of vision, happen when vitreous gel pulls on the retina. A sudden shower of multiple black dots in a person's field of vision may indicate retinal detachment and requires emergency medical attention. Sudden vision loss is another sign of a detached retina.