Visual outcome after corneal transplantation for corneal perforation and iris prolapse in 37 horses: 1998-2010.

The research studied the visual outcomes of horses that underwent corneal transplantation for iris prolapse between 1998 and 2010. The findings show that corneal transplantation, alone or in combination with adjunct treatments, can significantly improve vision in horses.

Objective and Methods

• The objective of the research was to understand the effects of corneal transplantation on horses having iris prolapse. Two types of treatments were studied: penetrating keratoplasty alone, and penetrating keratoplasty combined with overlying conjunctival or amniotic membrane graft.
• The research was based on a retrospective analysis of medical records of horses that were brought to the University of Florida Veterinary Medical Center for iris prolapse and were treated through penetrating keratoplasty from 1998 to 2010.
• About 37 horses were part of the study. The data collected included clinical descriptions of ocular lesions, treatments used, and the outcomes of the treatments.

Results

• All horses in the study had corneal ulcers leading to iris prolapses. All were initially treated for infection, hyperproteinase activity, and iridocyclitis.
• These horses were then treated surgically, either with penetrating keratoplasty alone or in combination with either a conjunctival pedicle flap, amniotic membrane transplant, or both.
• Majority of the treated horses (n = 24; 64.9%) showed good visual capability post operation. Some (n = 6; 16.2%) had limited vision, while others (n = 3; 8.1%) became phthisical and some (n = 4; 10.8%) had to have their globes enucleated.
• Post operation, all horses showed some degree of donor corneal graft opacification. Anterior synechiae were present in 48.6% of the treated eyes. Other common post-operative problems included wound dehiscence and aqueous humour leakage.

Conclusions

• The results of the study demonstrated that penetrating keratoplasty, either standalone or in combination with an overlying graft of conjunctiva or amniotic membrane, could significantly improve visual outcomes in a large proportion of horses suffering from iris prolapse.