Here’s a cat presented by the owner who had noticed an unusual change in appearance of her 6 year old cat’s eye. What is happening here and has it any consequences for the health of the eye and the cat in general?
What you are seeing here is a ballooning forward of iris tisue that is adherant at the pupil margin to the anterior lens capsule. Its what we call iris bombe and signals an anterior uveitis with posterior synechiae around the majority of the pupil margin. As far as the eye is concerned it may give glaucoma although the pressure here was 15mmHg, within normal limits. Actually I’ve been rather naughty here, since I should have told you that three weeks earlier the cat had an active anterior uveitis which we treated with atropine and steroids topically. Te inflammation has now calmed down but leaving the sequelae of this iris bombe. Treatment is quite tricky – one wants to break down the adhesions to relieve the bombe, but using atropine could be contraindicated where glaucoma may supervene and surgical intervention to breakdown the synechiae may have untoward effects in restarting the inflammation – notice the fibrin clot in the pupil showing that the eye is living on a knife edge of impending active inflammation.