PURPOSE: According to the Helmholtz theory of accommodation, one major cause of the development of presbyopia is the increasing sclerosis of the crystalline lens. One concept for regaining the elasticity of the sclerosing lens is intralenticular treatment by femtosecond laser pulses. METHODS: The feasibility of applying and imaging in vivo microincisions by femtosecond laser pulses was evaluated in five rabbit lenses with a new high repetition rate (100 kHz) femtosecond laser unit. The treated eyes were monitored using optical coherence tomography (OCT) and Scheimpflug imaging for localizing and studying the tissue effects of the incisions. The rabbits were investigated preoperatively, immediately postoperatively, and 14 days after treatment. RESULTS: The procedure, termed femtosecond-lentotomy, was successfully applied to the left lens of each rabbit. The laser microincisions within the crystalline lens were detectable with OCT and Scheimpflug imaging, which emphasizes the integral role these technologies play in targeting and characterizing postoperative tissue effects. The imaging within the lens showed a progressive fading of the incisional opacities generated by the femtosecond laser after 14 days with no detectable cataract formation. CONCLUSIONS: It is possible to create microincisions inside the crystalline lens within an acceptably short treatment time (<30 seconds). The 14-day follow-up did not show undesirable side effects, such as cataract formation, after intralenticular laser treatment.