What it is
In pannus the body's own defences start treating the cornea as something foreign. Immune cells, blood vessels and pigment move in from the edge of the cornea, laying down a film that gradually spreads towards the centre. The third eyelid can be affected too, its edge turning thick, pale or patchy.
It is an immune condition with an inherited tendency, and strong sunlight, ultraviolet light in particular, makes it worse, so it can be more active in dogs living at altitude or spending long hours outdoors. It can first appear in young adult or middle-aged dogs.
Pannus is a lasting condition, so your vet keeps checking the eyes over time. Shade on bright days spares the eyes, and a dog whose sight slowly dims still finds its way around a familiar home.
Signs you may notice
- Pink or dark patch on the eye
- Dull, cloudy eye surface
- Thickened edge of the third eyelid
- Changes in both eyes
- Mildly watery eyes
The first thing you may notice is a pink or dark patch at the edge of the cornea, for example at the outer corner of the eye, or that the eye has lost its shine and looks dull. Both eyes can be affected.
When to see a vet
Book a visit if you notice a pink or dark film creeping over the eye or the eye losing its shine, and contact a vet sooner if the eye turns red, seems painful or the dog appears to see less well.
This is general information, not veterinary advice. For your own dog's health, tests and treatment, see a vet.