Integrated fixation and stimulus channel for adaptive optics ophthalmoscopy

Adaptive optics (AO) ophthalmoscopes allow high-resolution imaging of retinal structure and function at the cellular level. Due to their high magnification and small field-of-view (FOV), these systems require precise fixation and light delivery to control the retinal region being imaged and stimulated. We present a high-efficiency fixation and stimulus channel for AO ophthalmoscopy, offering an extended working distance, wide steering range, and broad dioptric correction. For stimulation, the channel delivers intense, near-monochromatic light flashes across much of the visible spectrum. Our design uses all stock components, except for a 3D-printed conic mount and a few machined parts. We balance key system trade-offs and demonstrate design performance through several AO optical coherence tomography (AO-OCT) structural and functional imaging examples. Although originally developed for the Indiana AO-OCT system, these design principles can be readily applied to other AO ophthalmoscopic platforms.