Cat Third Eyelid Showing Both Eyes Treatment
If you notice a whitish or pinkish membrane covering part of your cat's eye surface in both eyes at once, you are seeing the third eyelid (nictitating membrane). This structure normally stays tucked in the inner corner and only appears briefly during blinking or when a cat is sleepy. When it protrudes visibly in both eyes for a prolonged period, it often signals an underlying health issue rather than a local eye problem. Understanding the possible causes and appropriate treatment steps can help you get your cat the care it needs.
Quick Q&A: Common Questions
Question: Why is my cat's third eyelid showing in both eyes? Answer: Bilateral third eyelid protrusion in cats is commonly associated with systemic illness, such as digestive upset, dehydration, or infections, rather than a primary eye disease. In young cats, it is often caused by a self-limiting condition called "Haw's syndrome" that accompanies intestinal inflammation or parasites. If both third eyelids are visible along with other symptoms like lethargy, vomiting, or diarrhea, a veterinary exam is essential to identify and treat the underlying cause.
What Does a Visible Third Eyelid Mean?
The third eyelid is a fold of tissue that contains a gland and helps protect the eye and spread tears. When it protrudes, it is often a sign that the eye is retracting into the socket (enophthalmos) or that the sympathetic nerve supply to the eye is disrupted. In both eyes, the cause is rarely a local injury or tumor; instead, it points to a systemic problem affecting the cat's overall health. The condition may be temporary and nonthreatening, but it can also indicate a serious illness requiring prompt veterinary attention.
Common Causes of Bilateral Third Eyelid Protrusion
Haw's Syndrome
Haw's syndrome is a common cause in young adult cats, especially those with a history of gastrointestinal issues such as diarrhea or inflammatory bowel disease. The third eyelids protrude symmetrically, but the eyes themselves appear normal and the cat often has no other eye symptoms. The condition is self-limiting and usually resolves within 2 to 4 weeks once the underlying digestive problem is corrected. No specific eye treatment is needed.
Dehydration and Electrolyte Imbalance
When a cat is significantly dehydrated (for example, from vomiting, diarrhea, or reduced water intake), the eyes may sink slightly into the sockets, causing both third eyelids to become prominent. Reintroducing fluids and addressing the cause of dehydration typically restores normal eyelid position within days.
Systemic Illness or Pain
Any condition that makes a cat feel generally unwell, such as a fever, infection, pancreatitis, or kidney disease, can trigger bilateral third eyelid protrusion. The cat may also show lethargy, loss of appetite, or hiding behavior. The eyelid return depends on treating the primary illness.
Neurological Disorders
Disruption of the sympathetic nervous system (Horner's syndrome) usually affects only one eye. However, certain neurological conditions or generalized weakness can affect both sides. If a cat has other neurological signs, such as head tilt, circling, or unequal pupils, a thorough neurological exam is warranted.
Normal Variation in Some Breeds
A small number of cats, particularly flat-faced breeds (e.g., Persians and Himalayans), may normally have slightly visible third eyelids. If this has been present since kittenhood and the cat shows no signs of discomfort or illness, it may be a normal anatomical feature.
When to See a Veterinarian
If both third eyelids are showing and your cat appears healthy, eating, and acting normally, you can monitor for 24 to 48 hours. However, schedule a veterinary visit if the protrusion persists longer than two days or if any of the following are present:
- Vomiting or diarrhea
- Lethargy or loss of appetite
- Discharge from the eyes or squinting
- Changes in behavior, such as hiding or irritability
- Signs of pain (vocalizing, reluctance to be touched)
Prompt evaluation is especially important for kittens, senior cats, or cats with known chronic conditions like kidney disease or hyperthyroidism.
Treatment Approaches
Treatment focuses on resolving the underlying cause rather than directly addressing the third eyelid. Your veterinarian will start with a full physical exam and may recommend diagnostic tests including blood work, urinalysis, fecal examination, or imaging.
- For Haw's syndrome, treatment involves managing the gastrointestinal upset, often with a bland diet, probiotics, or deworming medication. The third eyelids will recede on their own as the gut heals.
- For dehydration, fluid therapy (subcutaneous or intravenous) is the mainstay.
- For systemic infections, antibiotics or antiviral medications may be prescribed.
- If the cause is a chronic condition like kidney disease, ongoing management of that disease is necessary; the eyelid protrusion may fluctuate with hydration status.
In rare cases where the third eyelid does not retract after the underlying issue is treated, your veterinarian may recommend lubricating eye drops to prevent dryness. Surgery is almost never required for bilateral protrusion.
Home Care and Prevention
You can help your cat recover and reduce the risk of recurrent episodes:
- Ensure fresh water is always available and encourage drinking, especially in cats prone to urinary issues or kidney disease.
- Feed a balanced, high-quality diet to support gastrointestinal health.
- Keep up with routine veterinary checkups and parasite prevention, as intestinal worms can trigger Haw's syndrome.
- Monitor your cat's general behavior and body condition; any change in appetite or energy level warrants attention.
Never attempt to manually push the third eyelid back into place. This can cause injury or introduce infection. Instead, let the membrane return naturally as your cat's health improves. Most cases of bilateral third eyelid protrusion are temporary and resolve completely with proper care, giving your cat relief and restoring its bright, normal eyes.