What conditions would cause sudden onset and persistent bilateral medial corectopia in a person with previously centered pupils?

Several things..: If it is in fact corectopia, and not esotropia or pseudoesotropia, then the causes include progressive iris atrophy and other rare developmental anomalies, as well as post-traumatic scarring. None of these are likely to cause sudden onset of corectopia, though. Since these conditions can sometimes cause glaucoma, it would be best if an eye md (ophthalmologist) examined you.