Fig. 5. Ultrafast ophthalmic AO provides better focus stability and finer focus control in non-cyclopleged eyes.

a Consecutive AO-OCT retinal images acquired from a healthy 25-year-old male with conventional AO and ultrafast AO, respectively. See Supplementary Movie 1 for the full video. Each image is a projection of a volume along the fast-scan axis, and axial displacement of the retina between fast B-scans was corrected by aligning the photoreceptor layers. Blue arrowheads denote the time points when the DM actuators were updated. Note that AO updates within the OCT volume instead of at the beginning or end, thus the jump of system focus for conventional AO (indication of insufficient AO bandwidth) is more clearly seen in each image. COST cone outer segment tip, GCL ganglion cell layer, INL inner nuclear layer, IPL inner plexiform layer, IS/OS inner segment/outer segment junction, NFL nerve fiber layer, OPL outer plexiform layer. Scale bars = 50 µm. b Ultrafast AO enables fine focus control in the inner retina of a healthy 30-year-old male. The AO-OCT beam was focused at 11 depths sequentially from IPL to NFL with a step size of 0.02 D (≈7.4 µm). Each image is a projection of a cropped AO-OCT volume (the central 141 pixels of each fast B-scan) along the fast-scan axis. Scale bars = 50 µm.