The injection of cell suspensions or drugs into the subretinal space is a new promising option of vitreoretinal surgery for the treatment of degenerative retinal disorders. We used a manual oil-hydraulic microinjection pump to subretinally inject suspensions of retinal pigment epithelial cells in Royal College of Surgeons rats and in patients suffering from age-related macular degeneration with geographic atrophy. The histological examination of the treated rat eyes showed that cell suspensions could be placed precisely in the subretinal space. Intra- and postoperative outcome of the patients in the clinical trial revealed no retinal complications during 6 months of follow up. We suggest the oil-hydraulic microinjection pump to be a valuable instrument for controlled and precisely dosed atraumatic infusion or aspiration of small volumes of cell suspensions, fluids or drugs in vitreoretinal surgery.