During the therapy, the neurons sustaining residual function become more and more activated. Systematic stimulation is combined with an active perception task (pressing a button to confirm when points of light can be seen). This improves the visual information processing in the area of residual vision between the healthy and the clinically blind visual fields.

These neurons can be damaged totally (dark blue parts in the figure) by the diseases mentioned before, but there are also areas that are only partially damaged (lighter blue parts in the figure). However, the excitation of these neurons is normally not sufficient to mediate vision reliably.