This three week old snowy owl chick is presented to you blind, these lesions having been present throughout its short life. What might your differential diagnosis list be?
My first thought was that this was a very pronounced vascular keratitis possibly caused by an infection within the egg. But on closer examination the vessels moved independently of the underlying globe. In fact the nictitating membrane was tightly adhered to the conjunctiva on the opposite side of the globe, in a form of symblepharon. This was associated with a septicaemia – read more about the case in our paper Symblepharon with aberrant protrusion of the nictitating membrane in the snowy owl (Nyctea scandiaca). Veterinary Ophthalmology 6(1):11-3, 2003 which you can download on the recent publications page of this website.