Dear Nikola,

In "classical" ophthalmology, diffraction (colored) rings around
lights have been stigmatized as a sign of corneal swelling as a
result of acute sudden increase in eye pressure. (Very dangerous
acute angle closure glaucoma.) 

This dogmatic teaching, however, is contradicted by my subjective 
experience in that I see colored rings much of the time because 
the contact lenses which I wear are smudgy. In your case, I suspect 
that the diffraction rings are caused by a few pus cells which have 
not yet washed out of the tears. But of course, I can't be sure.
If vigorous blinking makes the colored rings go away, you've 
demonstrated that a slightly cloudy tear film was responsible. 
If in doubt and if an ophthalmologist is available, visit him; 
otherwise telephone me.

Jochen