Eyes - Let’s take a closer look!

By our Vet John Spearpoint

There are several common conditions affecting eyes that cause pain and distress and therefore pose serious welfare issues. But many of these can be easily treated if picked up early.

Pink Eye

Pink eye (Infectious Bovine Keratoconjunctivitis) usually occurs during summer and autumn and can vary from mild irritation to ulceration of the eye which, if left untreated, can lead to permanent blindness. It starts with damage to the cornea, the outside surface of the eye, from stalky grass, thistles, or wind and dust. The damage allows a highly contagious bacteria, Moraxella bovis, to attach to the surface of the eye and produce toxins which erode the cornea causing ulceration, pain and severe inflammation. Disease is easily spread by flies from one animal to another.

The first clinical signs of pink eye irritation appear as tearing (‘a crying cow’), staining below the eye or squinting with the eye held partially closed as the animal becomes more sensitive to light and pain. This quickly progresses to a cloudy spot in the centre of the eye which can expand to form a deep ulcer or divot/hole on the surface. Left untreated, pressure can build within the eye leading to rupture.

We commonly see pink eye mostly affecting youngstock but it can also affect any age group. Separating affecting animals can minimise further transmission and prompt treatment is important for a good recovery. Some animals may appear temporarily blind, so care must be taken when approaching and moving animals.

Treat pink eye with an antibacterial eye cream (Orbenin Eye Ointment). Half a tube per eye, repeated in 48 hours. And, as you can appreciate, anything to do with eyes is painful, so add pain relief (Ketomax or Meloxicam) to the treatment plan.

Depending on how badly the eye is affected, it may take several days, if not weeks, for the cloudiness to reduce. In advanced cases, permanent scarring/cloudiness may remain.

Cancer Eye

Cancer eye (Ocular Squamous Cell Carcinoma) as the name suggests, is a cancerous growth of the eye or surrounding tissues. The main risk factors are older animals, lack of pigmentation (white-faced animals) and sunlight causing UV damage.

Cancers usually start on the third eyelid as a wart-like growth, then spread to the surface of the eye and surrounding tissue. If detected early, and confined to the third eyelid (Figure 1), removal of the third eyelid can reduce the chances of it spreading further. This is a quick and cheap procedure if done early.

Once the cancer spreads to the outside surface of the eye (Figure 2), surgical removal of the entire eye and surrounding tissue is needed. These are malignant cancers so your vet will check to see if the cancer hasn’t spread into the head and lymph nodes. Cows recover quickly after eye removal and adapt well to having only one eye.

These cases can progress quite quickly, become infected and as a result have a bad smell or bleed easily. So, prompt removal of the cancerous cells can improve the chances of a successful surgery. If there is evidence of spread, the animal should be humanely euthanised as they are not fit for sale and will be condemned at the works.

Spotting eye problems can be difficult as the focus is usually on the rear-end of the cow during milking time. Regularly having someone paying attention to the side of the cow you don’t normally see can help to identify these cases earlier.