Fig. 4. There is a deep diffuse stromal edema in the central cornea of this eye with immune mediated endotheliitis.
and stromal edema in the central cornea which may evolve rapidly into bullous keratopathy (Figs. 4 and 5). Isolated arborizing blood vessels encroach upon the affected area at the level of Descemet’s membrane and/or endothelium. In some cases, dense clumps of cells may be evident adherent to the endothelium in the region of the terminal blood vessels. In long-standing cases stromal mineral- ization can occur. Rapid clearing of the cornea and regression of the blood vessels using topical dexa- methasone occurs in many cases of endotheliitis in the UK. It is a difficult disease in control in North America. Endotheliitis may be a precursor to glau- coma in the horse. Treatment should continue for a weeks following any corneal clearing. Recurrence of the disease is possible in a small number of long-
Fig. 5. The other eye in the horse in Fig. 4 has more diffuse edema.
standing cases. A successful outcome following pen- etrating keratoplasty has been reported in the U.S.
Acknowledgments
Conflict of Interest The Author declares no conflicts of interest.
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2. Matthews AG. Nonulcerative keratopathies in the horse. Equine Vet Education 2000;12:271–278.
3. Gilger BC, Michau TM, Salmon JH. Immune-mediated ker- atitis in horses: 19 cases (1998–2004). Vet Ophthalmol 2005;8 233–239.
