Adaptive optics using a liquid crystal spatial light modulator for ultrahigh-resolution optical coherence tomography

Three-dimensional ultrahigh resolution optical coherence tomography (UHR OCT) and adaptive optics (AO) are combined using a liquid crystal programmable phase modulator (PPM) as a correcting device for the first time. AO is required for correcting ocular aberrations in moderate and large pupils in order to achieve high resolution retinal images. The capabilities of the PPM are studied using polychromatic light. Volumetric UHR OCT images of the living retina with AO, obtained with up 25000 A scans/s and high resolution (~5x5x3 µm; transverse (x) x transverse (y) x axial) are recorded, enabling visualization of interesting intraretinal morphological structures. Cellular retinal features, which might correspond to groups of terminal bars of photoreceptors at the level of the external limiting membrane, are resolved. Benefits and limitations of the presented technique are finally discussed.