A cat’s inner eyelid, also known as the third eyelid or nictitating membrane, is an important part of their eye anatomy located in the inner corner. It functions primarily to protect the eye by lubricating, moisturizing, and removing debris 1. The inner eyelid is mostly concealed behind the lower eyelid and extends horizontally across the eye. It is normally only visible when pulled out from the corner or in certain relaxed facial expressions. The prominent inner eyelid contains a cartilage support, conjunctival membrane, and the drainage ducts for the tear film. Cats also have an extra layer of clear tissue called the nictitating membrane under the inner eyelid that can be pulled across the eye for protection.
The color of a cat’s inner eyelid can provide insight into their health. While it is commonly pinkish in color, changes in pigmentation may indicate an underlying issue. Some of the main inner eyelid colors to look out for are pale, dark, yellow, and spotted.
Anatomy of a Cat’s Eyelid
Cats have three eyelids. The third eyelid is called the nictitating membrane or inner eyelid. It is located in the inner corner of the eye. The inner eyelid contains cartilage and muscle tissue covered by a mucous membrane (Scientific American, 2015).
The inner eyelid functions to protect and lubricate the eye. It spreads tears across the surface of the eye and helps remove debris and foreign objects. The inner eyelid also provides extra protection for the eye during hunting or fighting. Cats have the ability to voluntarily control the inner eyelid, while it moves involuntarily in dogs (Scientific American, 2006).
Normal Inner Eyelid Color
The normal color of a cat’s inner eyelid is pink. This is due to the blood supply in the conjunctival membranes that line the inner eyelid. As blood circulates through the small blood vessels in the conjunctiva, it gives the tissue a pinkish hue. According to veterinarians, the inner eyelid of a healthy cat should be “a consistent light pink color” (Conjunctivitis in Cats – VCA Animal Hospitals).
A light pink inner eyelid is a sign that blood flow to the area is healthy. If the conjunctiva appears very pale or white, it could indicate anemia or decreased blood supply. Conversely, redder or darker pink tissue may signify inflammation or infection. So a nice light pink color is ideal and indicates normal, healthy eye tissue.
Pale Inner Eyelid Color
A pale inner eyelid in cats can be indicative of an underlying health condition. Some common causes of pale eyelids include:
- Anemia – Anemia is a reduction in red blood cells or hemoglobin. It can make the cat’s eyelids, gums, and other tissues appear pale or white. Causes of anemia include blood loss, immune-mediated disease, chronic kidney disease, cancer, infections like feline leukemia, and nutritional deficiencies (according to VCA Hospitals).
- Dehydration – When a cat becomes dehydrated due to lack of water intake, illness, or other causes, tissues like the eyelids can become pale. Severe dehydration requires prompt veterinary treatment with intravenous fluids (according to The Cat Practice).
- Shock – Any severe illness or trauma that leads to poor blood circulation and delivery of oxygen can result in shock. Shock makes the eyelids pale due to reduced blood flow. Emergent veterinary care is needed (according to Cornell Feline Health Center).
Some less common causes of pale eyelids include liver disease, hypothermia, and certain toxins. In most cases, the underlying condition causing the pale eyelids needs to be diagnosed and treated. Kittens with pale eyelids often have serious health issues requiring immediate veterinary care.
Dark Inner Eyelid Color
In some cases, a cat’s inner eyelid may appear darker than normal, even black or brown in color. This unusual darkening can be caused by a few different conditions:
Bruising – Trauma or injury around the eye can cause blood vessels in the inner eyelid to rupture and leak blood. This will lead to bruising and discoloration. The dark color should fade over time as the bruise heals.1
Melanoma – One potential cause of black or brown discoloration of the inner eyelid is a type of cancer called melanoma. Melanoma arises from pigment-producing cells called melanocytes. A dark-colored mass may be visible on the eyelid. Melanomas often require surgical removal.
Pigmentation – In some cats, the inner eyelid can develop dark pigmentation, especially as cats age. This benign pigmentation is not a cause for concern. However, it’s important to monitor the eyelid closely and ensure the pigment does not change or grow.
Regardless of the cause, any unusual dark color of a cat’s inner eyelid warrants a veterinary exam. Catching conditions like melanoma early is crucial. With treatment, many causes of dark inner eyelids can be successfully managed.
Yellow Inner Eyelid Color
A yellow coloration of a cat’s inner eyelid is often a sign of jaundice or liver disease. Jaundice occurs when there is a buildup of bilirubin, a yellow pigment produced when red blood cells break down. Under normal conditions, the liver filters out bilirubin from the blood. But liver damage or disease can cause bilirubin levels to rise, resulting in yellowing of the skin and membranes, including the inner eyelids.
Some common causes of jaundice and liver disease in cats include:
- Hepatitis – inflammation of the liver, often caused by infection.
- Cholangitis – inflammation of the bile ducts.
- Pancreatitis – inflammation of the pancreas, which can impair liver function.
- Liver cancer.
- Congestive heart failure – which can impair blood flow to the liver.
In addition to yellow inner eyelids, symptoms of liver disease can include loss of appetite, weight loss, vomiting, diarrhea, increased thirst, lethargy, and jaundice of non-eyelid skin and membranes. Diagnostic testing like blood work, imaging, and biopsy can help determine the underlying cause.
Treatment focuses on addressing the underlying condition causing the liver disease. This may include medications, intravenous fluids, dietary changes, surgery, or other interventions. Prompt veterinary care is important to stop and reverse liver damage before it becomes irreversible.
So in summary, yellowing of a cat’s inner eyelid is often indicative of jaundice and liver dysfunction. Seeking veterinary assessment as soon as eyelid discoloration is noted can help diagnose and treat the underlying condition early for the best outcome.
Other Inner Eyelid Colors
While the inner eyelid of a healthy cat is usually pale or pinkish, some cats can have less common inner eyelid colors like blue, red or purple. These unusual colors can be a sign of an underlying health issue.
A blue or purple inner eyelid is often a sign of a lack of oxygen in the blood. This condition, known as cyanosis, can occur for a variety of reasons including heart or lung disease, or a blockage in the cat’s airway.[1]
A red inner eyelid is generally indicative of inflammation or irritation. Allergies, infections, ingrown eyelashes or exposure to toxins can all cause the inner eyelid to appear red.[2]
If your cat’s inner eyelid is an unusual color like blue, purple or red, it’s important to have them seen by a vet. The underlying cause needs to be diagnosed and treated.
When to See a Vet
While pale or dark inner eyelids can be normal variations in some cats, abnormal eyelid color usually indicates an eye condition that requires veterinary attention. Here are some abnormal eyelid colors that warrant a trip to the vet:
Pale White: If your cat’s inner eyelid is stark white or a very pale pink, this can indicate anemia or blood loss. According to WSU Veterinary Hospital, severe anemia shows as a very pale or white third eyelid.
Bright Red: A bright red inner eyelid is often a sign of inflammation or infection. According to Quora, redness could indicate conjunctivitis, trauma, or a foreign object in the eye.
Dark Red/Purple: This eyelid color may indicate high blood pressure or a hematoma from bleeding into the eyelid tissue. According to Rover, dark red or purple hues warrant prompt veterinary care.
Yellow: A yellow or greenish inner eyelid can indicate liver disease, like hepatitis. According to WSU Veterinary Hospital, jaundice stemming from liver dysfunction shows as a yellow third eyelid.
If you notice any abnormal eyelid colors in your cat, make an appointment with your veterinarian right away. Catching eye issues early improves the chances of effective treatment.
Caring for Your Cat’s Eyes
Caring for your cat’s eyes is an important part of keeping them healthy and comfortable. Here are some tips for maintaining eye health and hygiene:
Clean the eyes gently every day with a soft, damp cloth to remove any discharge or crustiness. Use separate cloths for each eye to avoid spreading infection. You can also use sterile saline eye drops or wash made for pets to flush the eyes if needed.
Watch for signs of eye infections like redness, swelling, discharge or squinting and see a vet promptly if noted. Infections can worsen quickly in cats if left untreated.
Feed your cat a diet rich in vitamins A, C and E to support eye health. Foods like chicken, fish, eggs, carrots and leafy greens provide these antioxidants.
Don’t allow your cat to rub or scratch their eyes excessively as this can cause trauma. Clip nails regularly to minimize damage from scratching.
Protect your cat’s eyes from UV damage by not allowing them to sunbathe for prolonged periods. Cats with light eye color are especially prone to sun damage.
Schedule regular vet checkups to screen for eye diseases like glaucoma, cataracts and progressive retinal atrophy. Early detection allows for better management.
Keep household chemicals secured and avoid using sprays around your cat, as these can irritate eyes. Grooming products and flea treatments should also be kept away from the eyes.
Cats rely heavily on their vision and eye problems can impact their quality of life significantly. With attentive care and veterinary guidance, you can help preserve your cat’s eye health.
Conclusion
In summary, the normal color of a cat’s inner eyelid is pink or pinkish-red. This indicates healthy blood flow to the area. However, changes in inner eyelid color can signify potential health issues. Pale inner eyelids often indicate anemia or internal bleeding, while dark inner eyelids may signal fever or bruising. Yellow inner eyelids are a warning sign of jaundice, which requires urgent veterinary care. Other unusual inner eyelid colors like blue, gray, or white could indicate a systemic problem and also warrant a vet visit.
It’s important for cat owners to regularly monitor their pet’s inner eyelid color, along with checking for eye discharge or irritation. Rapid color changes or prolonged abnormal colors are causes for concern. Contact your veterinarian promptly if your cat’s inner eyelids are no longer pink. With close observation and care, you can help keep your feline friend’s eyes healthy.
