What is Cancers and Tumors of the Eye?
The tissues of the eye and eyelid can develop tumors or have tumor cells spread to those areas. Tumors on the eyelids and conjunctivae are the most common tumors in horses. Tumors within the actual eye are very rare and so are tumors within the eye socket.
Eye tumors and cancers in horses can be categorized as neoplasms of the eyelid or conjunctivae. Of these neoplasms and conjunctivae, most eye tumors are either squamous cell carcinoma (SCC) or sarcoid.
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Symptoms of Cancers and Tumors of the Eye in Horses
As a horse owner, it is your job to do a daily examination of your horse including checking the eyes for any abnormalities. When dealing with any part of the eye, it is always best to have your veterinarian assess the problem.
- Small sore or raised bump on the eyelid or near the eye
- Foul odor
- Rubbing the eye
- Restless moving of the head
- Excessive blinking
Causes of Cancers and Tumors of the Eye in Horses
There is still much that we do not know about what causes cancers or tumors of the eye in horses. Cancers are caused when cells begin rapidly multiplying, creating masses on or within the eye. SCC is caused by exposure to ultraviolet light such as spending excessive time in the sun.
Some horse breeds are more prone to cancers and tumors of the eye. Haflingers, Paints, Appaloosas and some Draft breeds are more prone to cancers and tumors of the eye.
Diagnosis of Cancers and Tumors of the Eye in Horses
Your veterinarian will do a full physical examination of your horse. A complete blood count (CBC) along with a urinalysis will be done to rule out other possible conditions. To determine what the growth on the eye or eyelid is, your veterinarian will do a biopsy of the growth.
If the condition is severe enough, your veterinarian may refer you to an equine ophthalmologist. The ophthalmologist will determine the best course of treatment for your horse.
Treatment of Cancers and Tumors of the Eye in Horses
Treatments will vary depending on the type of cancer or tumor of the eye. The size and location of the growth will also be a determining factor of the type treatments given.
Squamous cell carcinoma will be treated aggressively with anti-cancer medications, surgical removal of the growth, and cryotherapy. Smaller growths are easier to treat. Larger growths that are removed can require that your horse undergo reconstructive surgery since a larger amount of tissue had to be removed.
Equine sarcoids can be more difficult to treat because they have a high recurrence rate following surgical removal. Cryotherapy or laser surgery will be used to remove the growth. Chemotherapy and radiation may also be used to try to lessen the chances of recurrence. Sarcoids are rapid growing and recurrence before complete healing often happens.
Recovery of Cancers and Tumors of the Eye in Horses
If caught early enough, cancers and tumors of the eye can be treated. Follow your veterinarian’s advice and if an equine ophthalmologist is recommended, set an appointment quickly so treatments can start as soon as possible.
If the growth metastasizes, meaning the cancer cells have spread from that growth to other parts of the body, the prognosis is grave and can be fatal. In these cases, supportive care is most likely suggested until your horse’s quality of life diminishes and euthanasia is recommended.