This is also known as chronic superficial keratitis. Pannus is seen almost exclusively in German shepherds and German shepherd crosses.
Pannus is thought to be immune-mediated, meaning that the animals own immune system is contributing to the disease. Other factors playing a role in this disease are ultraviolet light, high altitude and chronic low grade irritation by dust and wind. Johannesburg and the surrounding highveld is the ideal environment for this condition to occur and that explains the very high incidence in this area.
Pannus is characterized by blood vessels growing into the cornea as well as inflammatory cells and pigment invading the cornea. It typically starts at the lower outside corner of the eye and gradually grows until the cornea is completely covered and the dog becomes blind.
A thorough examination would be necessary to differentiate this condition from other eye conditions that result in corneal pathology.
There are a number of treatment options. The ophthalmologist will decide and discuss the best treatment regime for the particular dog.