By our Vet Adam van den Broek
Eye ulcers are a relatively common problem in cats and dogs and can be caused by many different factors ranging from trauma to infection, and it is essential that they are assessed as soon as possible, to ensure appropriate treatment is given and the condition doesn’t worsen.
The outer layer of the eye is called the cornea, and it is this that becomes damaged in eye ulcers, and should be considered a potential emergency.
1) Trauma– most commonly seen in cats during fighting, and caused by a claw. These can be quite serious, with deep ulcers developing and risk of eye rupture if they are not treated quickly and correctly. Other causes that we commonly encounter at our surgery include grass seeds, so quite appropriate at this time of year.
2) Infection– bacterial, viral, possibly fungal. In cats that have had cat flu, this often becomes a chronic problem that waxes and wanes, and they often present with chronic, poorly healing eye ulcers.
3) Anatomical – for example in-growing eye lashes, or the lower eyelid rolling inwards towards the eye, and rubbing against the outer surface of the eye, the cornea and causing abrasion and damage.
Other anatomical causes can be related to dog breed, for instance what are known as brachycephalic dogs- i.e. Bull dogs, pugs and so on, who have short noses and faces, and eye balls that tend to bulge, the eyes are not always fully protected by the eye lids. This makes their eyes more vulnerable to trauma and irritation, and thus more at risk of corneal injury and ulcers.
Dogs and cats with eye ulcers show varying signs that include squinting, watery eye or possibly a mucky discharge that may be purulent and infected. The eye may appear red or cloudy, and the third eye lid in the corner of the eye may be more prominent.
To diagnose corneal ulcers we will start by looking at the eye with an ophthalmoscope, assess the eye to see if there are adequate tears, as this can cause ulcers, and then apply some dye called fluorescein into the eye. The dye sticks to areas where the cornea is damaged, and thus highlights where the ulcer is, as sometimes this is not apparent to the naked eye.
Swabs can also be taken to assess for viral, fungal and bacterial causes and the appropriate treatment can be given.
1) Eye drops, including antibiotic, lubricating, the latter important to help and create the right environment to promote healing.
2) Serum– this is used sometimes in non-healing ulcers as it contains enzymes that can combat substances produced by bacteria that destroy the cornea.
3) Instillation of local anaesthetic into the eye and then debriding on the eye with a cotton bud to remove dead cells and promote healing.
Likewise sometimes a grid is scratched on the surface of the cornea over the ulcer to help with healing.
4) Surgery– if the ulcer is not healing and deteriorating, and there is a risk of rupture, the this may be required to protect the ulcer and again promote healing.
This can involve the use of the third eyelid as a flap to cover the ulcer, but is not ideal as the ulcer cannot be visualised, also it doesn’t give a blood supply to the site to help with healing. Conjunctival pedicle grafts, where a flap of the conjunctiva inside the upper eye lid is sutured over the ulcer is a better option as it gives a blood supply and healing is more rapid.
In extreme cases if the ulcer won’t heal and the eye becomes non-viable due to permanent damage, loss of vision, or other complications such as secondary glaucoma, then removal of the eye is sometimes required.
5) Contact lenses are sometimes used to provide protection to a non-healing ulcer.
6) Adjunctive treatments such as painkillers may be required also, but it is important to note that steroids should be avoided at all costs, including topical ones, as these will delay healing and most likely worsen the ulcer.
Buster collars or equivalent may be required to prevent self-trauma to ulcer.