Do uveal cysts cause misbehavior in horses?

Do uveal cysts cause misbehavior in horses? Usually these are enlarged corpora nigra and rarely cases have appeared where these almost occlude the iris certainly hampering vision. Somewhere in-between normal and obviously vision hampering cysts is the horse with enlarged corpora (cysts) that have misbehaviors that might be related to altered vision: spooking, refusals, awkward head carriage, etc.. Since we cannot ask the horse, it is always a bit of guess whether the behavior is related to altered vision or not. This paper takes a look at 48 cases to see if the procedure had a positive outcome and, in the cases where follow-up was available it was reported that the horses’ problems had resolved.
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Outcomes Following Transcorneal Diode Laser Ablation of Uveal Cysts: 48 Horses (2006-2020)
J Equine Vet Sci. 2021 Jul;102:103640.
Authors
Kimberly Lam 1 , Stephanie A Pumphrey 2
Affiliations

1 Department of Clinical Sciences, Tufts University Cummings School of Veterinary Medicine, North Grafton, MA.
2 Department of Clinical Sciences, Tufts University Cummings School of Veterinary Medicine, North Grafton, MA. Electronic address: stephanie.pumphrey@tufts.edu.

Abstract

Uveal cysts can lead to undesirable behaviors and poor performance in horses. Transcorneal laser ablation has been proposed as a safe and effective treatment for uveal cysts suspected of causing behavioral changes but outcomes have been reported in only a small number of horses. In this retrospective study, records were identified for horses who had undergone transcorneal cyst ablation using a diode laser. Information was collected regarding signalment, behavioral or performance issues reported prior to the procedure, and complications. Owners were contacted to provide follow-up information regarding resolution of behavioral issues. Seventy eyes from 48 horses were treated. Undesirable behaviors or performance issues were reported prior to the procedure in 35 horses, and follow-up information was provided for 22 of those horses. Of these 22 horses, 59% of owners reported significant improvements in behavior or performance, 27% reported some improvement, and 14% reported no improvement. No significant complications were reported in association with the procedure. Although follow-up data were available for only a subset of horses, transcorneal diode laser ablation was an effective means of resolving owner-reported behavioral or performance complaints believed to be caused by uveal cysts for many of the horses in this group. Further work is needed to assess effects of uveal cysts on equine behavior and to characterize effects of transcorneal diode laser ablation prospectively.

Keywords: Behavior; Corpora nigra; Cyst; Equine; Laser; Ophthalmology.