Seeing flashing lights out of the corner of the eye when there are none. This is usually caused by mechanical stimulation of the retina.

awareness of momentary flashes of light

The appearance of bright streaks of light or lightening like flashes often caused by the mechanical action of vitreous traction on the retina. May be more noticeable with rapid or violent head movement. An new or sudden increase in light flashes may be a precursor to retinal tears.

a sensation of instantaneous flashes of light; most commonly indicative retinal traction.