Understanding the Link Between Worms and a Cat’s Third Eyelid
Cats communicate a great deal through their eyes, and subtle changes can signal significant health issues. One such change is the visibility of the third eyelid, also known as the nictitating membrane. Normally tucked away and barely visible, a prominently raised third eyelid can be a major red flag for underlying health problems—including the presence of intestinal worms.What Is the Third Eyelid?
The third eyelid is a thin, protective membrane located in the inner corner of a cat’s eye. It helps protect the eye from dust and scratches and plays a role in tear production and immune defense. When a cat is healthy, this membrane isn’t usually visible except for a tiny portion during rest.
Possible Causes of a Raised Third Eyelid
When the third eyelid becomes prominently visible, it can indicate various issues:
- Infections – Viral or bacterial conjunctivitis
- Eye injuries – Trauma to the cornea or eye socket
- Neurological disorders – Conditions like Horner’s syndrome
- Vestibular disease – Inner ear and balance system dysfunction
- Gastrointestinal issues – Especially common in cases of parasitic infestations
How Worms Could Be the Cause
A condition known as Haws Syndrome is often linked with gastrointestinal disturbances, including intestinal worm infestations. In this syndrome, both third eyelids may become elevated without any obvious eye injury. The exact mechanism is not entirely understood, but irritation and inflammation in the gastrointestinal tract are believed to trigger a reflexive response affecting the eyes.
Other Symptoms That May Accompany Worm Infestation
If your cat’s third eyelid is visible, look for additional clues of parasitic infection:
- Weight loss despite a good appetite
- Diarrhea or vomiting
- Visible worms or worm segments in feces
- Dull coat or signs of poor grooming
- Lethargy and reduced playfulness
Diagnosis and Treatment
To determine whether worms are causing the appearance of the third eyelid, a veterinarian will typically perform a physical examination and recommend fecal testing. If parasitic worms are found, treatment involves:
- Administering appropriate deworming medications
- Supporting overall digestive health
- Monitoring the cat’s hydration and nutrition
Eye-specific treatments are usually not needed if the root cause—worms—is addressed effectively. The third eyelid generally returns to a normal position post-treatment.
When to See a Veterinarian
Even if you suspect worms are the cause, it’s crucial to consult a veterinarian whenever your cat’s third eyelid remains raised for more than a few hours. Other serious conditions can produce similar signs and require different treatments. See a vet immediately if the third eyelid is accompanied by:
- Squinting or eye discharge
- Loss of balance or head tilting
- Changes in appetite or behavior
Prevention Tips
Preventative care can help reduce the likelihood of third eyelid issues linked to gastrointestinal parasites:
- Regular deworming as advised by your vet
- Clean litter box practices
- Routine veterinary check-ups
- Minimizing exposure to potential contamination sources like rodents or contaminated soil
Conclusion
A cat’s raised third eyelid may be unsettling to observe, but it's an essential signal of potential health problems, including intestinal worm infestations. Since Haws syndrome can stem from gastrointestinal irritation, treating the underlying worm infection often resolves the eye issue without direct ocular intervention. Immediate veterinary care ensures accurate diagnosis, proper treatment, and the return to your cat’s healthy, alert-eyed demeanor.





