Purpose: To report the safety of a newly developed intraocular lens (PC/IOL) with reversibly adjustable refractive power (*Acri.Tec AR-1 PC/IOL) after implantation into adult human eyes. The surgical setup and specially designed instruments required for implantation will be evaluated. The examined parameters included: stability of the IOL during implantation, positioning of the IOL, rotation of the IOL, integrity of the posterior lens capsule, central visual acuity, morphology of the eye, clinical signs of inflammation, intraocular pressure, refraction. Methods: The study was carried out on 35 human eyes after using the Acri.Tec AR-1 PC/IOL after lens removal through phacoemulsification; as control, the implantation of conventional PC/IOL into the second eye of 29 patients was used. The mean follow-up was 9 + 6 months. An initial adjustment surgery of the *Acri.Tec AR-1 PC/IOL was carried out 2 weeks after implantation in 2 patients; the follow-up of these eyes was 3 and 6 months. Results: Implantation was possible without any problem. Eyes healed normally. No difference between eyes containing the *Acri.Tec AR-1 PC/IOL and eyes containing conventional PC/IOLs could be detected with respect to visual acuity, stabilization of refractive error, signs of inflammatory reaction, slitlamp microscopic aspect of the eye and intraocular pressure. As intended, initial adjustment surgery successfully changed the mydriatic refraction from +1.0 resp. +0.75 dpt to 0 resp. –0.5 dpt. 26 bilaterally pseudophakic patients including 2 patients having had adjustment surgery had more than 3 months follow-up. Mean visual acuity in the AR-1 PC/IOL group at 3 months (0.76 ±0.24) did not differ from mean visual acuity in the pseudophakic control group (0.74 ±0.23). Adjusted eyes had a visual acuity of 1.0. No adverse effects occurred. Conclusion: Initial data suggest that the *Acri.Tec AR-1 PC/IOL can be safely implanted into the capsular bag of adult human eyes and can beadjusted after implantation, thereby achieving the desired change of refraction. Further exploration of the potential usefulness of this type of reversibly adjustable PC/IOL as a tool for refractive optimization is warranted.