Eye Cancer (Ocular Neoplasia) in Cats

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Last updated on
4 min read

Key takeaways

Tumors of the eye, defined as abnormal cell growth in or around the eyes, are uncommon in cats.

  • Most eye tumors are malignant, aggressive, fast-growing, and likely to spread throughout the body where they have serious consequences
  • Benign tumors are less common, typically slow-growing, and cause damage when they apply pressure to surrounding structures
  • Tumors occur within the eyeball (intraocular), in the tissue surrounding the eyeball (conjunctival), or on the surface of the eye (ocular)
  • Tumors of the eye tend to be primary, meaning that they arise from the eye itself
  • Secondary tumors of the eye develop from cells originating elsewhere in the body, with lymphoma being the most common source of secondary eye tumors
  • Biopsy to determine cell type is required for diagnosis, and prognosis and treatment depend on the type of cancer
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A closer look: Eye Cancer (Ocular Neoplasia) in Cats

Cancer is defined as abnormal, uncontrolled cell growth. In most cases, this uncontrolled cell growth can develop into definite masses called tumors, including tumors in the eye and related structures.

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Risk factors

Symptoms associated with discomfort such as squinting, rubbing the face, and eye discharge occur in many cases. Blindness occurs in severe cases, depending on tumor type.

The average cat is at low risk of ocular tumors. Cats are less likely to suffer from ocular tumors than dogs, but those that do are more likely to have malignant tumors. Benign ocular tumors in cats are very uncommon.

Contributing factors for some specific types of eye tumors include:

  • Environmental factors, such as UV light exposure, increase risk of melanoma of the eye
  • Post-traumatic sarcomas are caused by trauma or inflammation of the eye
  • Feline leukemia virus (FeLV) increases risk of cancer in general, including ocular lymphoma.

Possible causes

The cause of most cancers is complex, and is often never identified. Most cases likely have a combination of genetic and environmental factors contributing to the development of cancer.

Main symptoms

Symptoms depend on the location and tissue affected. Changes in the appearance of the eye common with ocular tumors.

Testing and diagnosis

Suspicion of eye cancer starts with physical changes to the appearance of the eye, noted on physical exam. Testing the pressure inside the eye, tear production, and imaging such as X-rays, CT or MRI provide more information.

Biopsy is required for definitive diagnosis. Surgical removal of the eye is often necessary for biopsy results.

Blood work, vitals, and imaging of the chest and abdomen help in assessing the general health of an affected cat.

A veterinary ophthalmologist and oncologist referral is often recommended to understand prognosis and expected outcome.

Steps to Recovery

Surgical removal or laser ablation of affected tissue is curative in some cases. Other cases benefit from radiation and chemotherapy. Palliative care (hospice) and humane euthanasia are important considerations in severe cases when quality of life is affected or prognosis is poor.

Prognosis depends on the type of cancer. In cases where surgical removal is curative, prognosis is excellent. Malignant tumors have a higher risk of spreading and a poorer prognosis.


Most ocular tumors in cats are not preventable, but decreasing UV light exposure and minimizing trauma to the eye helps prevent specific types.

Ocular tumors are not contagious, but retroviral infections that predispose cats to cancers are. Spaying and neutering cats and vaccinating cats against feline leukemia virus may indirectly decrease the risk of certain eye tumors.

Is Eye Cancer (Ocular Neoplasia) in Cats common?

Ocular tumors are uncommon in cats.

Typical Treatment

  • Surgical removal
  • Laser ablation
  • Chemotherapy
  • Radiation therapy
  • Palliative care
  • Euthanasia


Kirk N. Gelatt , VMD, DACVO - Writing for MSD Veterinary Manual
Ralph E. Hamor , DVM, MS, DACVO - Writing for MSD Veterinary Manual
Georgina M. Newbold, DVM, DACVO / Diane Van Horn Hendrix, DVM, DACVO - Writing for Clinician's Brief
Richard R. Dubielzig, DVM, DACVP - Writing for Veterinary Partner

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