Eye infections

The eye is an organ that allows a person or animal to perceive their environment. It is therefore also called a sensory organ or sense. Just like any other organ, there can be conditions that hinder the organ’s functioning. In this article, we’ll discuss some common acute eye conditions and how to treat them. 


The horse can develop an infection of the mucous membranes of the eye. This is called mucosal inflammation, conjunctivitis or fly eye. The name fly eye originated because the condition mainly occurs in the summer and there are more flies that can cause irritation. Other causes are allergic reactions, a cold or irritation due to dust, for example. The mucous membranes will become red and swollen, but the cornea will remain undamaged. The pupils have a normal size and the pupillary reflex is also present. If the vet has determined that the horse has mucosal inflammation, it can be treated well with an antibiotic eye ointment, possibly with a corticosteroid. To prevent further irritation, you could put a fly mask on the horse. If the mucosal inflammation persists for a long time, the tear duct may become blocked, and this will need to be examined and treated. 


Moon blindness is also an eye infection, but then of the membranes on the inside of the eye (the uvea). Another name for moon blindness is uveitis or ERU (Equine Recurrent Uveitis). It is a very painful condition of which the cause is not fully known. It is probably caused by a bacterial infection in the eye, but an immune response by the immune system can also play a role (an autoimmune disease). If the horse has moon blindness, the cornea may be normal or slightly cloudy and a kind of white-blue flakes may become visible. The pupil is small and has no pupillary reflex. In addition, there may be a lot of tear fluid and the eyelids can swell. With this condition, there is a high chance that the infection will keep coming back and cause more and more damage to the eye. Even so much damage that the horse may go blind in that eye. Treatment of moon blindness consists of eye drops or eye ointment containing a corticosteroid and atropine eye drops. The horse is also given pain medication. Through medication, the vet tries to inhibit the inflammation and limit the associated damage, but unfortunately this is not possible in all cases. 


A horse’s eye is a sensitive organ. It is therefore important to immediately contact the vet if you suspect an eye condition. In general, you can recognize an eye condition if the horse keeps their eye (partially) closed, it is red and/or swollen and there is a lot of tear fluid. The vet can then examine the eye further to make the correct diagnosis and draw up a treatment plan. 

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