Enucleation is a surgical procedure that involves removal of the eyeball (“globe”), as well as some of the eye’s adjacent connective, muscular, and glandular tissues. The procedure can be performed in a sedated, standing horse or with the horse on a surgical table under general anesthesia. Local anesthetic, to numb the area around the eye, is used to eliminate discomfort during the procedure. Two variations of surgical technique can be used for removal of the eye: transpalpebral and subconjunctival enucleation. The procedure performed by an ACVS board-certified veterinary surgeon is selected based on the eye disease that is affecting your horse.
Transpalpebral enucleation is conducive to limiting the spread of infection or cancer and is sometimes combined with an approach to remove a large amount of the associated tissue in the eye socket. Subconjunctival enucleation is performed more commonly to treat conditions that are contained within the eyeball and will allow the veterinary surgeon to preserve a greater bulk of the adjacent tissues. It is important that glandular tissue associated with the eye is always removed during an enucleation, as their remnants may cause chronic drainage from the site of eye removal. Limiting the removal of muscle and connective tissue from the eye socket, or the placement of an eyeball prosthetic, gives a more esthetic appearance to the horse after surgery. It is important to note that not all horses will be candidates for a prosthetic; your ACVS board-certified surgeon can help you determine if it would be an option for your horse.
Horses that are blinded or pained by inflammatory, infectious, or cancerous conditions that fail treatment, or carry a poor prognosis with treatment, should be considered candidates for enucleation. Animal owners may also elect to pursue enucleation when their horse is affected by a condition requiring intensive care that can’t be feasibly treated due to financial or management constraints. Diagnosis of eye disease and the plan for enucleation is often made by a veterinary surgeon in conjunction with an ACVO board-certified veterinary ophthalmologist.
Enucleation is commonly performed to treat horses affected by:
- Ocular trauma or a foreign body
- Perforating corneal ulceration
- Cancer, such as squamous cell carcinoma
- End-stage uveitis or glaucoma
- Improved comfort and quality of life for the horse when a painful eye is removed (many horses can return to athletic disciplines)
- Prevention of the spread of infection or cancer
- Limitation of medical labour and costs when a horse’s eye is affected by chronic disease
- Submission of the eye for microscopic analysis may provide a diagnosis that will guide appropriate care of the remaining eye
- Loss of vision, which may be life threatening for the horse if the remaining eye becomes diseased or injured
- Horse owners should be especially cognisant of their own safety when working around the blind side of their horse
- Modified appearance to the horse’s head after surgery