Long-term regulation of retinal function in RPE65-deficient dogs following subretinal injection of the AAV2/4TetOff.rpe65 vector. Affected dogs (a) A1, (b) A2, and (c) A3 before injection and at different time points postinjection, in the ON and OFF states. The b-wave amplitudes of the ERG max. (scotopic) of the treated and untreated eyes were measured and reported in the graphs. Gray, treated eye; black, untreated contralateral eye. The ON state was obtained in the absence of Dox, whereas the OFF state was obtained upon oral administration of Dox. bi, before injection; ERG, electroretinography; mpi, months postinjection.