Companion Animals

Third Eyelid Prolapse in Cats: Welfare and Diagnosis

Understanding Haws syndrome and other causes of third eyelid elevation in cats.

Key Facts

Bilateral third eyelid prolapse in cats is most commonly Haws syndrome — a benign condition
Haws syndrome typically follows gastrointestinal illness and resolves in 4-6 weeks
Unilateral prolapse is more concerning — warrants investigation for local or systemic cause
Horner's syndrome, masses, and eye infections all cause unilateral prolapse

Welfare Considerations

Third eyelid prolapse causes ocular discomfort and impairs vision in some cats. Welfare management depends on accurate diagnosis — bilateral Haws syndrome requires monitoring only, while unilateral prolapse warrants prompt investigation. Replacing a prolapsed nictitating membrane gland (cherry eye) surgically is preferable to excision — preserving the gland protects long-term tear production.

What You Can Do

Seek veterinary assessment for any cat with visible third eyelid — especially if unilateral
Resist pressure to remove the gland in cherry eye — ask about repositioning surgery
Monitor cats with Haws syndrome for resolution over 4-6 weeks without intervention