Phosphene fading

The rapid perceptual adaptation by which a phosphene evoked by steady stimulation dims and disappears within seconds, in both retina and cortex. Because a static electrode pattern therefore cannot hold a static image, prostheses must continually refresh, modulating amplitude or timing, or exploiting eye and head movement, to keep percepts visible.

Fading constrains stimulation and encoding design: it favors change-driven, temporally varying strategies and interacts with gaze-contingent rendering, since the small image shifts from eye movement can themselves refresh the percept. It is distinct from long-term threshold drift, which is slower and reflects tissue changes rather than neural adaptation.