When your cat's eye just won't get better: Feline Temporary Partial Tarsorrhaphy

Feline Temporary Partial Tarsorrhaphy

Cats are prone to a number of eye problems, some of which are easy to overcome and others which are not. Kittens can suffer from chronic upper respiratory infections that may damage the eyes (corneal ulceration and corneal sequestrum). Cats of any age can scuffle and scrap with each other and injure an eye (corneal laceration), or stick their noses where they don't belong and get foreign objects in their eyes. Injury, illness or genetic defect can cause the eyelids to roll inwards (entropion), allowing the fur on the face to rub against the cornea and cause irritation.

Whatever the cause, sometimes eye drops or eye ointment are not sufficient to quickly and effectively treat an eye problem. In these cases, a special eye surgery called a temporary partial tarsorrhaphy can be performed to help protect the eye and aid in healing. In some cases a complete tarsorrhaphy is necessary.

This surgery involves suturing the eyelids together so that the cat cannot open its eye fully. The temporary closure of the eyelids allows the cornea to heal without allowing additional damage from irritants, self-trauma (rubbing at the eye or blinking excessively), or excessive drying.

This may sound distressing, but cats tolerate it quite well, because it relieves much of the pain and irritation associated with the affected eye. A partial closure allows a cat some visibility from the eye (and allows the veterinarian to continue to monitor healing), and medications can still be applied to the eye.

Pre-surgery, Ricky was squinting and uncomfortable

10 week old Ricky was one such kitten who needed additional help. He came to us from a rescue and was under the care of a veterinarian. He had been bottle raised, and had been battling upper respiratory infections since he had been found. Both eyes were treated with both an oral antibiotic and two different eye medications - an antibiotic drop and an antibiotic ointment. One eye recovered nicely, but unfortunately, his right eye just did not want to heal. Additionally, whether due to a birth defect or due to chronic illness, the eye was smaller in size than normal, so the eyelid was rolling inwards, allowing his fur to rub up against the surface of the eye every time he blinked and causing further irritation and inflammation.

Dr. Demos performed a temporary partial tarsorrhaphy on his right eyelids, closing part of the eye to prevent the eyelid from rolling in, and to relieve irritation to the cornea. Within minutes of recovering from anesthesia, little Ricky was bouncing around and playing and eating like nothing had happened. We started him on an oral antibiotic and a different topical antibiotic drop and we will check his healing in about 7 days.

 

Post-surgery, Ricky really got into his food

Case study: Sally - Progressive Retinal Atrophy (PRA) in cats

Sally

 Sally is a 3-year-old Abyssinian cat that was rescued from a hoarding situation. She was one of 84 cats rescued. Eighty of the cats in the household were too ill or debilitated to survive and had to be euthanized. After adoption, it was discovered that Sally was Feline Leukemia positive. She is shy, but sweet, and her owners brought her in to us because she suddenly appeared to lose her sight. She began bumping into things and lost her fear of the dog. If you notice in her photo, her pupils are very dilated, and her owners had noticed this at home, too. Her regular veterinarian sent her to us because high blood pressure was suspected.

What does high blood pressure have to do with eyesight?

The retina lines the back of the eye

The retina is a thin membrane lining the inside of the eye that receives light and translates it into electrical impulses for the brain with special cells called photoreceptors. There are two kinds of photoreceptors - rods that process black and white or dim light vision and cones that process colors or bright light. If the retina or its photoreceptor cells become damaged in some way, the eye has trouble converting waves of light into signals that the brain can understand, interfering with a cat's vision.

 One of the ways that cats can lose their vision is by developing hypertension lesions in the retinas - tiny blood vessels are damaged and regions of the retina lose their ability to function as they lose their blood supply. These lesions look like bubbles in the retina. If a cat's blood pressure remains elevated for a long period of time, the retina can completely detach and lose its connection with the nerves that transmit visual impulses to the brain. Once this has happened, a cat becomes irreparably blind. If the hypertension is diagnosed and treated early, as in these photos, the retinal lesions can heal over time.

Retinal lesions appear like bubbles in the back of the eye

The same eye 2 months after starting blood pressure medication

 Notice that not only are the lesions gone, but the blood vessels appear more visible.

The first thing that we did when Sally came in was check a blood pressure reading. Her blood pressure was 150mmHg, which is a normal pressure in a nervous cat. Hypertension was not the culprit in this case. So, what could be the problem?

The next thing that happened was that Sally received a full physical exam from Dr. Demos, including an eye exam. This is what Dr. Demos saw when she looked in Sally's eyes...

Something very important is missing, here!

There are no blood vessels in this retina!
This is a characteristic feature of something called Progressive Retinal Atrophy (PRA). PRA is a recessive trait in certain breeds of cats such as the Abyssinian, the Somali and the Ocicat. Perisans and Siamese are also often at risk. There are a number of other breeds that have also been identified to carry the mutated gene in small numbers.

Other key features of this disease are a granular appearance to the retina, signs of retinal thinning, and a reduction or thinning of blood vessels. Increased reflectivity of the retina and dilation of the pupils are symptoms that owners can easily see at home. Later stages show pigment changes to the retina and a degradation of the optic nerve. These changes usually happen equally to both eyes at the same time.

Sally's pupils stay dilated, even in bright light

The most common form of PRA in cats is involved a progressive degeneration of the rod and cone receptors in the retina.The cat's eyes develop normally as a kitten, but as the cat gets older, the cat will begin to experience night-blindness and may tend to avoid stairs or darkened areas of the home. It will progress to total blindness by the age of 3-5 years. This is problematic not only for the cats themselves, but for the breeders of high-risk breeds, because often the disease is not apparent until after the age at which many cats have already participated in a breeding program. If you are interested in a purebred cat, it may be a good idea to ask your breeder about PRA and whether their cats have been genetically tested for the mutation.

Unfortunately, this is a problem for which there is no treatment. However, the good news is that cats adapt well to being without their sight due to their superior hearing, sense of smell and sense of touch (whiskers). You can read about the amazing cat, Homer, who caught flies out of the air without the aid of sight!

If your cat starts to show reluctance to move around at night, or has trouble jumping onto furniture, or starts to bump into things, it would be a good idea to have your cat's eyes checked by his or her veterinarian, as well as having a blood pressure exam performed.