  The classical Cauchy completion of a metric space (by means of Cauchy
sequences) as well as the completion of a uniform space (by means of Cauchy
filters) are well-known to rely on the symmetry of the metric space or uniform
space in question. For qausi-metric spaces and quasi-uniform spaces various
non-equivalent completions exist, often defined on a certain subcategory of
spaces that satisfy a key property required for the particular completion to
exist. The classical filter completion of a uniform space can be adapted to
yield a filter completion of a metric space. We show that this completion by
filters generalizes to continuity spaces that satisfy a form of symmetry which
we call uniformly vanishing asymmetry.
