Efficacy and safety of suprachoroidal triamcinolone injection in horses with poorly responsive equine recurrent uveitis

Objective: Equine recurrent uveitis (ERU), a chronic, immune-mediated intraocular inflammatory disease, is a common cause of blindness in horses. The severity and recurrent nature of ERU makes it difficult to treat with current therapeutics leading to a poor visual prognosis. The suprachoroidal space (SCS), a potential space between the choroid and sclera surrounding the ocular posterior segment, offers a promising alternative site for drug application to the eye. Corticosteroid administration within this space is hypothesized to be safe and effective at controlling intraocular inflammation, especially in horses with poorly responsive ERU. Animal studied: Horses with active, poorly responsive ERU. Procedure(s): A retrospective study was performed with 29 horses (36 total eyes) that received SCS injection of triamcinolone acetonide (TA) with ERU not well controlled with standard uveitis treatment. A standardized ocular inflammation score (OIS) was used to assess inflammation at the time of injection and at follow-ups. Results: Standardized OIS revealed a significant decrease in ocular inflammation over time after SCS TA administration (p <.004). Adverse effects after injections occurred in <20% of the horses at follow-up, but some of these effects were attributed to chronic inflammation prior to effective treatment, long-term topical corticosteroid use, or complications from hospitalization rather than the SCS injections. Most horses (86.7%) in this study remained visual greater than 3 months after SCS injection. Conclusions: Based on these results, SCS TA injections appear to be a safe and possible effective treatment modality for managing poorly responsive ERU; further clinical study is warranted.