  In optical imaging, light propagation is affected by the inhomogeneities of
the medium. Sample-induced aberrations and multiple scattering can strongly
degrade the image resolution and contrast. Based on a dynamic correction of the
incident and/or reflected wave-fronts, adaptive optics has been employed to
compensate for those aberrations. However, it only applies to
spatially-invariant aberrations or to thin aberrating layers. Here, we propose
a global and non-invasive approach based on the distortion matrix concept. This
matrix basically connects any focusing point of the image with the distorted
part of its wave-front in reflection. A singular value decomposition of the
distortion matrix allows to correct for high-order aberrations and forward
multiple scattering over multiple isoplanatic modes. Proof-of-concept
experiments are performed through biological tissues including a turbid cornea.
We demonstrate a Strehl ratio enhancement up to 2500 and recover a
diffraction-limited resolution until a depth of ten scattering mean free paths.
