Wavenumber-space wavefront sensorless adaptive-optics for optical coherence tomography

Adaptive-optics optical coherence tomography (AO-OCT) allows the visualization of cellular-scale retinal structures; however, its adoption both at research and clinical levels has been restricted by hardware and software complexity. Based on the observation that aberrations other than defocus are depth-independent, we propose an approach for wavefront sensorless AO-OCT that utilizes the interferometric fringe modulation in wavenumber (<i>k</i>-) space to optimize the wavefront correction. This approach avoids the need for tomogram reconstruction at each optimization iteration and increases robustness against axial motion. The proposed routine combines <i>k</i>-space optimization with focal plane shifting (i.e., defocus optimization) and evaluates the objective function B-scan-wise, achieving 8 Zernike modes correction in ∼1.89 s. Experimental testing with a phantom model eye and computational complexity analysis show the proposed algorithm has a lower computational complexity and faster optimization time per mode while performing at least as well as depth-resolved optimization, using a LabVIEW implementation without the need for high-performance dedicated software or GPU acceleration. We demonstrate its performance in human retinal imaging <i>in vivo</i>.