Enucleation is the medical term for the removal of the entire eyeball. Removing the eye is often a tough decision for the pet owner to make, but always the right one. Cats do fine with one eye and can live out a long and happy life. The loss of an eye should have minimal impact on your cat’s quality of life. In most cases, it will improve if your cat has been living with pain and discomfort for a while.
There are several indications for enucleation where the eye is either blind or painful, which are unresponsive to treatment.
- Tumours – This may either be cancer of the eye (on the outside or inside the globe) or cancer behind the eye. There are several types of cancer that can affect the cat’s eye, including iris melanoma, conjunctival squamous cell carcinoma, intraocular lymphosarcoma and iris/ciliary body melanoma. These cancers have the potential to spread (metastasise) to other parts of the body. Most information discusses the removal of the eye due to intraocular malignancy; however, in some cases, cancer may be behind the eye, such as in the case of my cat who had osteosarcoma.
- Eye infection or inflammation – There are many causes of eye infection or inflammation in cats some are the result of infections such as herpes, injuries or scratches that may occur to the eye resulting in an infection that remains unresponsive to treatment.
- Severe glaucoma – Increased pressure within the eye which causes pain and loss of sight.
- Phthisis bulbi – A shrunken and non-functional globe that occurs due to trauma or severe ocular disease.
- Severe trauma – Such as a globe rupture. There is always a risk that the cat will develop sympathetic ophthalmia, in which the undamaged eye becomes inflamed and can potentially lose vision. Removing the damaged eye prevents this condition.
- Congenital deformities – These deformities are present at birth and may render the eye unworkable or defects can lead to permanent damage over time requiring the eye be removed.
Enucleation is a last resort surgery when there is no hope of sparing the eye or for cases where the cat is in chronic pain.
There are several surgical methods, including transconjunctival (subconjunctival) and transpalpebral. The surgery itself takes approximately one hour.
Before surgery, the veterinarian will discuss with you the option of a prosthetic eye; there are no benefits to this other than aesthetics.
- A 12 hour fasting period will be necessary before surgery. This is a safety measure in case your cat vomits while he is unconscious.
- The area around the eye is clipped (eyelashes trimmed) and disinfected with a povidone-iodine solution.
- The cat is put under general anesthesia.
- The surgery itself varies depending on the technique and is beyond the scope of this article. A detailed explanation of enucleation surgery can be found here. The entire globe, eyelids, muscles, soft tissue around the eye and optic nerve are removed. The area is sutured closed with dissolvable stitches or stitches which will require removal 10-14 days after surgery.
The cat will be prescribed antibiotics, painkillers, and anti-inflammatories at the time of discharge. Administer as instructed.
The cat will wear an Elizabethan collar until the surgical site has healed, which takes between 7-14 days.
Mild swelling is normal after surgery, due to the formation of a hematoma underneath the eyelid. If you notice severe swelling or oozing from the area, contact your veterinarian immediately. A warm compress can relieve discomfort.
Keep the cat inside during the recovery period.
The time it takes to recover will depend on the age and overall health of your cat. Your cat will experience some soreness and possibly swelling for a few days post-surgery. Some cats will bleed from the nose following surgery; this is normal and should stop within 1-2 days.
Long-term the outcome is good; there will be some loss of binocular vision; however, most cats adapt well and do fine with just one eye.