  Microscope objectives achieve near diffraction-limited performance only when
used under the conditions they are designed for. In non-standard geometries,
such as thick cover slips or curved surfaces, severe aberrations arise,
inevitably impairing high-resolution imaging. Correcting such large aberrations
using standard adaptive optics can be challenging: existing solutions are
either not suited for strong aberrations, or require extensive feedback
measurements, consequently taking a significant portion of the photon budget.
We demonstrate that it is possible to pre-compute the corrections needed for
high-resolution imaging inside a glass tube based on a priori information only.
Our ray-tracing based method achieved over an order of magnitude increase in
image contrast without the need for a feedback signal.
