TDK conference 2016

Equine recurrent uveitis (ERU) is the most common ophthalmic disease in horses. It is an immune-mediated inflammatory disease of all parts of the uvea. Due to it’s chronic and recurrent progression and destruction of intraocular structures, ERU frequently causes blindness. Clinically, ERU affected horses show signs of blepharospasm, conjunctival hyperaemia, aqueous flare, posterior synechiae, cataract formation and chorioretinitis. Several studies have dealt with the etiopathogenesis-, diagnostics as well as the conservative and surgical treatment methods of this intraocular inflammation with different outcomes. Because of potential side effects of applied medication, the risk of doping in the case of sport horses and the problem of future uveitis episodes, a traditional medicated treatment is not always feasible.

This circumstance requires other promising therapeutic approaches, such as the pars plana vitrectomy and the insertion of a cyclosporine-A drug delivery device. The literature provides varying perspectives on both of the aforementioned methods. Besides the successful pars plana vitrectomy, the cyclosporine-A implant is proposed and applied with an increased frequency due to its nature of being an easier and financially lucrative operation technique. According to the literature the vitrectomy is recommended only for Leptospira positive tested horses.

We selected 21 horses diagnosed with ERU that were initially examined by ophthalmological specialists beforehand and treated with a subscleral cyclosporine-A implant. Leptospira antibody testing on the vitreous samples of the 21 horses was performed using micro-agglutination test (MAT). Between 2013 and 2016 17 out of this 21 horses were treated with vitrectomy. 8 out of the 17 horses were tested positive for intraocular Leptospira antibodies. 9 of the 17 horses have been tested intraocular Leptospira negative. The outcome of the vitrectomy and the postoperative course of the horses was followed up. Out of the 8 Leptospira positive tested horses 7 showed no further uveitis relapses postoperative, while none of the horses tested negative for Leptospira antibodies continued to episodes of ERU.

This study yields promising results that the vitrectomy should be the selected method instead of the cyclosporine-A implant even in the case of Leptospira negative tested horses.