Use of intravitreal injection of gentamicin in 71 horses with equine recurrent uveitis

We report a retrospective evaluation of intravitreal gentamicin (6 mg in 0.3 mL solution) injection in 71 horses with equine recurrent uveitis between 2010 and 2016. Aqueous flare and hyalitis were scored at the baseline in all horses, then at 15, 30, 60, 90, 180, 365, and 730 in 37, 46, 30, 25, 22, 18, and 11 horses, respectively. Forty-two animals had a global score of inflammation (sum of scores for aqueous flare and hyalitis) of zero at the last examination (number of re-examinations per horse ranged from 1 to 5). Among the 29 remaining horses, four were not reassessed after the intervention. The individual inflammation scores of the remaining 25 horses improved in 21 cases, whereas it slightly deteriorated in four cases (number of re-examinations ranged from 0 to 6). Ocular hypotension, lens opacities, and retinal folds were observed, respectively, in 92%, 78%, and 28% of the 71 eyes at the baseline, and in 80%, 90%, and 36% of the 11 eyes re-evaluated at 2 years. A telephone inquiry about all horses among owners and referring veterinarians conducted in 2016 at least 6 months after the more recent injections indicated that 70 horses did not develop a new observable episode of inflammation and did not need ocular medication. Although the results of this study should be discussed with reservation, it indicated that low-dose intravitreal injection of gentamicin could be a useful treatment to maintain ocular quiescence in equine recurrent uveitis.