Coherence gating and adaptive optics in the eye

An en face coherence gated camera equipped with adaptive optics (AO) has been constructed for imaging single cells in the living human retina. The high axial resolution of coherence gating combined with the high transverse resolution of AO provides a powerful imaging tool whose image quality can surpass either methodology performing alone. The AO system relies on a 37-actuator Xinetics mirror and a Shack-Hartmann wavefront sensor that executes up to 22 corrections per second. The coherence gate is realized with a free-space Michelson interferometer that employs a scientific-grade 12-bit CCD array for recording 2-D retinal interferograms. Images were collected of microstructures the size of single cells in the in vivo retina. Early results suggest that a coherence gated adaptive optics camera should substantially improve our ability to detect single cells in the retina over the current state-of-the-art AO retina cameras, including conventional flood illuminated and confocal scanning laser ophthalmoscopes. To our knowledge, this is the first effort to combine coherence gating and adaptive optics.