"Cancer Eye" is a term commonly used in the cattle industry to describe an invasive tumour of the eye region which occurs relatively frequently in cattle in Australia.
A genuine eye cancer is almost always a Squamous-cell Carcinoma (or SCC) which is commonly a very malignant tumour, with the malignancy taking the form of local invasion of the tissue. This can be compared with other types of malignant tumours which are "metastatic", meaning cells from the tumour break off and travel round the body settling out in other areas such as lungs or bone and producing "secondaries" of the same tumour.
Because SCCs of cattle eyes are normally invasive rather than metastatic, they can often be completely removed and the condition cured even though the tumour is highly malignant.
The key is obviously to identify the tumour early enough before it invades tissues around the eye which cannot readily be removed, such as the bony eye socket.
The SCC in our picture had begun on the third eyelid, and already spread to the conjuctiva of the eye and the surface of the eyeball itself. Fortunately all these structures were able to be removed, using sedation and regional anaesthesia which allow the cow to remain standing during the procedure.
Cancer Eye can quite rightly (as identified by some of our quiz answers) be confused with a different condition called "Pink Eye". Pink Eye is actually a serious inflammation of the very same structures susceptible to Cancer Eye (the conjunctiva, third eyelid and surface of the eyeball) but this time caused by bacterial infection.
Your vet can identify the difference between these two serious eye diseases. Fortunately Pink Eye can be treated - the best treatment is with systemic antibiotics rather than just application of a topical ointment or spray - and also responds well to early intervention.
Here again the key is to observe the changes in the animal's eye early enough to make treatment effective and increase the likelihood of a total cure.
Interestingly SCC in cattle is more of a problem in Australia than in Europe which is where most of the cattle in our area have their ancestry. This is because of the correlation between exposure to sunlight and development of SCCs - horse owners may be aware that these tumours often also develop in the white skin and eye structures of horses with no skin pigment in those areas such as few-spot apaloosas and some paints or pintos.
Historically this has led to some breeds such as Herefords and Holsteins being genetically selected for pigmented faces. As you can see by our picture, however, being black around the eyes does not guarantee that a squamous cell carcinoma will not develop in individual animals.