RGCs go into a regenerative state 4 d after axotomy accompanied by lens injury. a-c, Retinal explants from mature rats after 48 hr in culture. Retinas were subjected to no previous treatment (a), axotomy alone 4 d before explanting (b), or axotomy plus lens injury 4 d beforehand (c). d, Quantitation of results: axons per explant after 24 or 48 hr in culture. Data represent results from normal retinas (0) or from retinas subjected to axotomy (Axot), with or without lens injury, 1-7 d beforehand, as indicated.