This rabbit has had an inflammatory episode of uncertain aetiology and ends up with this strange corneal appearance. I’m indebted to Alice Courtney for this great picture. What do you think might be going on here and does it shed any light on what happened to cause the problem?
This white circle with a target lesion centrally in a somewhat oedematous cornea with an inflammatory ‘muddy’ loss of intraocular detail, is most probably a Wessely ring; that is to say a circle of antibody-antigen complex deposition with the antigen coming most probably from a central traumatic event and the antibody from blood vessels at the limbus. Its the same sort of deposit that gives an immunopreciptate in an agar gel preciptation assay, as here, where antigen is placed in one well and antibody in the other. While this is a classic corneal appearance it is very rare – I’ve never seen one before apart from in experimentally induced situations in textbooks. Topical anti-inflammatory and antibiotic treatment has been used here with some success but it is a shame that we don’t know which antigen(s) are involved. Suttorp-Schulten and colleagues produced a paper documenting the changes that occur in such a lesion: The fate of antigen-antibody complexes in the rabbit cornea. Current Eye Research 1991 10:773-8 and
Meyers-Elliott has documented the condition occuring with corneal herpesvirus infection in people: Viral antigens in the immune ring of Herpes simplex stromal keratitis. Arch Ophthalmol. 1980 98:897-904.