Canine Pannus (Chronic Superficial Keratitis): Eye Welfare and Management

Pannus in Dogs: Protecting Vision and Welfare

Pannus (chronic superficial keratitis, CSK) is an immune-mediated inflammatory eye condition causing progressive corneal vascularisation, pigmentation, and scarring. Without appropriate management, pannus causes significant visual impairment — a major welfare concern. The condition is predominantly seen in German Shepherd Dogs, Greyhounds, Border Collies, and their crosses, with UV light exposure as a key trigger.

Pathophysiology

Pannus involves abnormal cell-mediated immune response targeting corneal tissue, particularly when UV light stimulates immune dysregulation in genetically predisposed individuals. Inflammatory cells invade the normally avascular corneal stroma, followed by ingrowth of blood vessels (vascularisation), deposition of pigment (melanin), and eventually fibrous scarring. These changes, starting at the temporal-lateral limbus and spreading centrally, progressively impair light transmission and vision.

Clinical Signs and Progression

Early pannus appears as subtle pinkish-grey haze or faint vascularisation at the temporal corneal margin. Progressive disease shows clearly visible blood vessels across the corneal surface, grey-brown pigmentation, and eventually granulation tissue. In severe or unmanaged cases, pigment covers the visual axis, causing significant vision impairment and potentially blindness. A third eyelid (nictitating membrane) plasmacytoma frequently accompanies corneal pannus.

Welfare Impacts

While pannus is not painful in most cases, progressive visual impairment significantly reduces quality of life — affecting confidence, mobility, and play behaviour. Dogs with advanced, unmanaged pannus may show: reluctance to navigate unfamiliar environments, reduced activity, anxiety in changing light conditions, and collisions with objects. Early diagnosis and consistent treatment prevents these welfare consequences.

Treatment

Pannus is managed (not cured) with lifelong topical immunosuppression:

• Topical corticosteroids: Dexamethasone or prednisolone eye drops/ointment 2-3 times daily for induction, reducing to maintenance frequency. Effective but require monitoring for complications
• Topical cyclosporin: Optiimmune ointment or compounded cyclosporin drops — effective immunosuppression with fewer long-term concerns than steroids in some cases
• Tacrolimus: Alternative topical calcineurin inhibitor for cyclosporin-resistant cases
• UV protection: Doggie goggles (Rex Specs) significantly reduce UV-induced flares, particularly in high-altitude and high-UV environments

Monitoring and Long-term Welfare

Regular ophthalmoscopic examination every 3-6 months monitors disease progression and treatment response. Treatment frequency adjustment prevents relapse while minimising medication requirements. Well-managed pannus patients maintain clear vision throughout their lives — demonstrating the welfare importance of early diagnosis, owner education, and consistent treatment compliance.

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