Effects of topical homatropine on pupil diameter (PD) intraocular pressure (IOP) in the normal horse eye

Recurrent equine uveitis (ERU) is an important eye disease that causes secondary ocular changes such as lens dislocation, glaucoma, and retinal damage as chronic inflammatory lesions become chronic, making it the most common cause of blindness in horses worldwide. Homatropin is used as a mydriatic drug with pupil dilation and ciliary muscle relaxation during acute iris inflammation. The aim of this study was to evaluate the effect of Homatropin 2% eye drops on pupil diameter and intraocular pressure (IOP) in healthy horses. For this purpose, 20 apparently healthy horses of cross breed with an age range of 5-14 years and a weight range of 310-220 kg were selected. At each stage, IOP parameters and pupil size were measured before dropping, then repeated 15, 30, 60 and 120 minutes after the last drop. Data were then analyzed using one-way ANOVA analysis. The present study showed that there was a statistically significant difference between the treatment and control groups in the studied horses to determine IOP and homatropin decreased IOP at 15, 30 and 60 minutes compared to the control group (P <0.05). In this study, the effects of homatropin on pupil diameter were not significant. A supplementary study on the efficacy of homatropin in the treatment of EUR disease in horses with this disease is recommended.