Adaptive optics - optical coherence tomography (AO-OCT) has the potential to improve lateral resolution for OCT retinal imaging. Several reports have already described the successful combination of AO with a scanning confocal Fourier-domain OCT instrument to permit real-time three-dimensional (3D) imaging with high resolution (in all three dimensions). One of the key components that sets the performance limit of AO is the wavefront corrector. Several different wavefront correctors have been used in AO-OCT systems so far. In this paper we compare two commercially available wavefront correctors: an AOptix Bimorph deformable mirror (DM) and a Boston Micromachines Micro-Electro Mechanical System (MEMS) DM (used for the first time in an AO-OCT system). To simplify the analysis, we tested their performance for the correction of low-amplitude high-order aberrations (with minimal defocus and astigmatism). Results were obtained with an AO-OCT instrument constructed at UC Davis that combines state-of-the-art Fourier-domain OCT and an AO design to allow simultaneous testing of both mirrors without the need to modify the optical system.