A 5-year-old castrated male Thoroughbred was referred to the North Carolina State University College of Veterinary Medicine Equine Ophthalmology Service for evaluation of cloudiness and ble- pharospasm of the right eye. Ten days prior to evalua- tion, the horse had injured the right eye during train- ing as a hunter-jumper performance horse, resulting in a penetrating injury to the lateral cornea near the lim- bus. The cornea was sutured, and the referring veteri- narian placed a conjunctival flap over the site of the injury. The horse was treated with frequent topical and systemic administration of antimicrobials and nons- teroidal anti-inflammatory medications. The horse appeared comfortable immediately following surgery, but developed cloudiness and blepharospasm 7 days later. The horse was referred because of suspected endophthalmitis in the right eye as a result of the pen- etrating injury. On initial examination at North Carolina State University, the horse had moderate blepharospasm and epiphora in the right eye. Hypopyon and fibrin that filled the anterior chamber of the right eye obscured the view of the iris, lens, and posterior segment of the eye. There was no menace response in the right eye or consensual pupillary light reflex from the right eye to the left. The left eye appeared normal. A B-mode, 10- MHz ocular ultrasonographic a examination revealed hyperechoic material interpreted to be hemorrhage or inflammatory cells 1 in the vitreous body and complete retinal detachment with a large dorsal retinal tear. Because of the hypopyon, suspected vitreal hemor- rhage or cellular infiltrate, and complete retinal detach- ment, a grave prognosis for vision and retention of the eye was given, and enucleation was recommended. Microbial or phacoclastic endophthalmitis was sus- pected. 2,3 The owner hoped that the horse could return to performance competition after recovery from the injury; therefore, a cosmetic prosthesis was considered. To provide an implant that would not become loosened during competition, had a low rate of rejection, and provided enhanced motility of the ocular prosthesis and better cosmesis, an integrated orbital prosthesis using a hydroxyapatite sphere 4-6 was recommended. Placement of a hydroxyapatite sphere for fixation of a cosmetic prosthesis was performed as described for use in humans 4-6 with modifications for use in the equine orbit. A normal equine eye was enucleated from a euthanatized horse 24 hours prior to surgery. The sclera was cleaned of extraocular muscles and the cornea and intraocular contents removed, leaving a scleral shell. This donor scleral shell was placed in 100% ethanol b for 24 hours prior to surgery. Immediately prior to surgery, the donor sclera was soaked in 1 L of warm sterile saline (0.9% NaCl) solu- tion c for 1 hour. A 40-mm-diameter hydroxyapatite sphere d that had been sterilized in a standard steam autoclave was soaked in 5% cefazolin solution e for 1 hour and then placed within the donor scleral shell (Fig 1). Medial and lateral releasing incisions in the sclera, originating from the corneal opening and extended posteriorly, were made to allow introduction of the hydroxyapatite sphere into the interior of the donor scleral shell. These incisions were closed in a simple continuous manner with 5-0 polyglactin 910. f The horse was anesthetized and prepared for surgery. A retrobulbar nerve block was administered with 10 mL of 2% lidocaine HCL. g Flunixin meglumine (0.5 mg/kg [0.23 mg/lb]) h and potassium penicillin G (22,000 U/kg [10,000 U/lb]) i were given IV. A 4-0 nylon j suture was passed through the upper conjuncti- JAVMA, Vol 222, No. 3, February 1, 2003 Scientific Reports: Clinical Report 343 EQUINE Use of a hydroxyapatite orbital implant in a cosmetic corneoscleral prosthesis after enucleation in a horse Brian C. Gilger, DVM, MS, DACVO; Stefano Pizzirani, DVM; Lisa C. Johnston; Nicholas R. Urdiales ' Placement of a cosmetic prosthesis is desired after enucleation of equine eyes to allow horses to return to competition. ' Hydroxyapatite orbital implants made from marine coral allow vascular and fibrous tissue growth from the host orbit into the implant and may provide excellent cosmesis. From the Department of Clinical Sciences, College of Veterinary Medicine, North Carolina State University, Raleigh, NC 27606 (Gilger, Pizzirani); and E. R. Johnston & Associates Inc, PO Box 1201, Benson, NC 27504 (Johnston, Urdiales). The authors thank Jacklyn Salmon and Cassandra Nixon for techni- cal assistance. Address correspondence to Dr. Gilger. Figure 1—Photograph of a hydroxyapatite sphere within the sclera of an eye from a donor horse prior to implantation into the orbit of a horse treated by enucleation because of hypopyon. Notice sutured lateral releasing incisions made to allow the sphere to be inserted into the sclera.