Return to work following unilateral enucleation in 34 horses (2000-2008).

This research studied the impact of unilateral enucleation (removal of one eye) on a horse’s ability to return to its previous work role. It found that the removal of one eye does not significantly affect the likelihood of a horse’s ability to go back to its function, regardless of the horse’s age, discipline or which eye was operated on.

Objectives of the Research

• This study aimed to evaluate the influence of unilateral enucleation on a horse’s ability to resume its previous discipline or occupation.
• The factors examined included a horse’s age at enucleation, the discipline it was involved in, the reason for the enucleation, the onset of vision loss, and which eye was removed.
• The primary hypothesis was that the removal of one eye does not significantly affect a horse’s ability to return to work.

Methodology of the Study

• The research was carried out by conducting a retrospective review of medical records of horses that underwent unilateral enucleation at the University of Pennsylvania New Bolton Center between April 2000 and April 2008.
• Various case variables were determined from the medical records, including the horse’s breed and sex, the horse’s age at enucleation, the reason for the enucleation, the onset of vision loss, and which eye was removed.
• The researchers then carried out telephone interviews with the owners or trainers of each horse to find out about the horse’s pre- and post-operative occupations.

Results of the Study

• The study found that 85% of horses (29 out of 34) that had undergone unilateral enucleation returned to work in their previous roles. This mainly included pleasure or trail riding, flat racing, hunter/jumpers, dressage, group lessons, eventing, steeplechase, and breeding.
• Only 12% of horses (4 out of 34) did not return to work, which was due to anticipated or perceived decrease in performance or behavioural change following unilateral enucleation. An additional horse retired due to lameness issues unrelated to the enucleation.
• Among the horses that experienced acute vision loss, 88% (22 out of 25) returned to their previous discipline, compared to 78% (7 out of 9) among those with gradual vision loss.

Conclusions of the Study

• Based on the findings, the researchers concluded that horses are generally capable of returning to a variety of occupations after undergoing unilateral enucleation.