It is a condition that arises from the pattern and location of the retinal vascular, branching in front of the photoreceptor layer. The arrangement casts a shadow causing a person to see black spots, floating bodies, circles of light, etc., only when the front section of the eye is illuminated. The presence or absence of the phenomena can serve as an indicator for posterior and anterior abnormalities, and refractive and convergence disorders. It makes them potential pointers of disease presence and progression.