Foveal cone optoretinography using a reflective mirror-based line-scan adaptive optics OCT

We introduce reflective mirror-based line-scan adaptive optics line-scan OCT, optimized for imaging light-induced retinal activity (optoretinography) and weak retinal reflections at the cellular scale. The performance was exemplified by cellular-scale visualization of retinal ganglion cells, macrophages, foveal cones, and rods in human observers. Light-evoked optical changes in foveal cones were observable at an eccentricity 0.3 deg. from the foveal center, enabling the first in vivo demonstration of reduced S-cone (short-wavelength cone) density in the human foveola. Given the challenges typically associated with optical accessibility in the living human fovea, this instrument holds significant promise for basic and translational applications.