Iris abscesses with and without intralenticular fungal invasion in the horse

To describe clinical and histologic findings in horses with iris abscesses. Design Retrospective medical records study.

Medical records of horses that had iris abscesses at the University of Florida Veterinary Medical Center, Peterson & Smith Equine Hospital, and Veterinary Eye Specialists of London, Ontario, from 2005 to 2008 were reviewed.

Data collected from the medical records included signalment, clinical and histologic descriptions of ocular lesions, therapy, complications, and visual outcomes.

The medical records of two Quarterhorses, one pony, one warmblood, one Westphalian, and one Arab horse with unilateral iris abscesses were identified. Mild-to-severe clinical signs of iridocyclitis were present in all six eyes with iris abscesses. The eyes of two horses with iris abscesses were also associated with deep stromal abscesses and responded to medical therapy alone in one case, and medical therapy and corneal transplantation in the other. Iris abscesses in two horses were also associated with intralenticular invasion due to a Cladosporium and a Fusarium-type fungus respectively, and resulted in enucleations. Two horses with iris abscesses and no apparent lens involvement resolved with medical therapy in one case and surgical removal of the iris abscess and medical therapy in the other.

This is the first clinical report of iris abscesses in the horse, and the first histologic report of fungal invasion of the horse lens.