This ten year old male entire Border Collie is presented with gradually developing visual disturbance but suddenly a painful right eye. What is the obvious corneal condition in both eyes, why might it be leading to ocular pain and what can be done about it?
This dog has severe corneal oedema. The possible causes of this are (in order of importance to the eye not prevalence) glaucoma, CAV-1-associated uveitis, endothelial degeneration or dystrophy, though the latter is less likely given the age and breed of the animal. Intraocular pressure was normal and thus with the age of the animal and the gradual onset of the condition, endothelial degeneration is most likely. The endothelium is vital in maintaining the correct level of corneal hydration and thus dystrophy, degeneration or damage through increased intraocular pressure or endothelitis in CAV-1-induced uveitis can curtail its function leading to corneal oedema. Norice the irregular light reflection from the right cornea. Here stromal water has resulted in subepithelial bullae which have burst giving painful corneal ulceration. The best treatment for such bullous keratopathy is thermokertoplasty where a hot wire is used to scar the central cornea, thus preventing formation of further bullae (Michau et al: Use of thermokeratoplasty for treatment of ulcerative keratitis and bullous keratopathy secondary to corneal endothelial disease in dogs: 13 cases (1994-2001). J Am Vet Med Assoc. 2003 222(5):607-12).