What are Corneal Ulcers?
Corneal ulcers are quite a common occurrence in cats. However, if it goes unchecked, it could lead to much discomfort and total loss of vision.
If it wasn’t for the cornea, it would be a dark world for your cat. One of its most important functions is supporting vision by allowing light to pass through it into the eye so that your cat can enjoy the beauty of sight as much as you do. It also protects the inner parts of the eye from harmful elements such as bacteria and any other foreign objects including chemicals by the simple virtue of being the eye’s outer layer. Corneal ulcers occur when the outermost part of the cornea is broken.
Symptoms of Corneal Ulcers in Cats
Corneal ulcers are quite painful. It is, therefore, not too hard to notice when they descend on your feline pet. When your cat shows the following signs, it’s time to see a vet:
- Squinting and sensitivity to bright light
- Discharge from the affected eye
- Reddening of the eye due to inflammation
- Clouded cornea
- Rubbing and pawing at the affected eye
- General signs of problems with the cat’s vision
Remember, the cornea is made up of four layers. While the epithelium is the outermost part and protects the inner layers from permeation by water and harmful elements, the second layer is the basement membrane which separates the epithelium from the third one—the stroma. The innermost layer is the endothelium. Classified into various groups, the type of corneal ulcers is determined by the affected part of the cornea.
- Superficial ulcers affect only the epithelium.
- Deep ulcers go past the epithelium into the stroma.
- Descemetoceles go deeper into the endothelium, which is also known as the descemet’s membrane, sometimes leading to perforation of the eye.
Causes of Corneal Ulcers in Cats
The appearance of corneal ulcers in your cat could be as a result of any of the countless causes. While the level of harm to the eye could be as damaging as any other, it could be as a result of such a trivial thing as an ingrown eyelash. In most cases, however, the causes are more serious. They include:
- Infections by bacteria and virus
- Exposure to harmful chemicals
- Dirt under the eyelid
- Injuries sustained during a fight or play
- Dry eye
- Paralysis of the facial nerves
Remember, if your cat is young, it is an easy target for Feline herpesvirus (FHV). The virus may affect your cat for the rest of its life through recurrence. Nevertheless, it does not happen in every case.
Diagnosis of Corneal Ulcers in Cats
If you think your cat is in trouble from corneal ulcers, the best step to take is to have it examined. Usually, the veterinarian will conduct an observation of the affected eye with the help of fluorescein dye. The presence of the condition is confirmed by a greenish color on the affected part of the eye. The coloration is caused by binding of the fluorescein to the ulcerous tissue.
Keep in mind that the descemet’s membrane does not absorb the dye. In case of descemetoceles, therefore, there will be a bulge. If the fluorescein dye is used, the condition will reveal its presence through a green boundary and a dark circle.
To determine whether the problem is caused by facial nerve paralysis, the function of the facial nerves is analyzed. A Schirmer’s test is necessary in case of dryness of the eyes. It involves the insertion of paper strips into the eyes to determine whether the amount of tears produced are enough to keep the eyes wet.
Treatment of Corneal Ulcers in Cats
One of the main considerations during treatment of corneal ulcers is the seriousness of the condition. Among the most important aims is pain relief, prevention of the spread of fungal or bacterial infection and control of the inflammation. However, different types of the condition require different levels of attention and treatment. The restoration of the eye to its exact former self will depend on the severity of the ulcer and the treatment administered.
Antibiotics are usually administered in cases of superficial corneal ulcers. They help reduce the cat’s suffering from pain and halt any contractions of the ciliary muscles as well as protect the affected eye against infections. However, remember that the use of antibiotics including atropine may lower the production of tears and thus negatively affect the healing process. While superficial ulcers normally require a period of not more than a week to heal, cats suffering from the herpes virus will have to be put on medication permanent ly due to recurrence of the condition.
In case your cat has ulcers going deeper past the stromal layer, it may be necessary to take more complicated measures including corneal suturing, corneal transplant, conjunctival flaps and grafts and contact lenses. Apart from providing structural support, surgical therapy is important in repairing of the cornea and restoring its normal functions. Conjunctival flaps, for example, are helpful in instantly supplying blood to the cornea and helping in provision of important requirements for healing.
Keep in mind that the island graft doesn’t initiate a blood supply. Therefore, a way of supplying blood to the cornea should be available for it to be fully effective. In addition, an antibiotic ointment will have to be applied on the eye for a minimum of the first 10 days after surgery, three to four times every day. After two weeks, the flap should have stuck to the cornea.
Recovery of Corneal Ulcers in Cats
Even with superficial ulcers, your cat needs frequent and consistent attention from the veterinarian. Some of them are too stubborn to heal within as short a period as you would expect. In that case, dead tissue needs to be removed to allow the growth of new ones. Since scraping is involved, the cat has to be put under anesthesia.
Remember, the application of ointments should be frequent. In case of corneal ulcers caused by dryness in the eyes, the cat could be provided with artificial tears. In addition, it should be put under close observation to ensure that it doesn’t paw at the treated eye or put it in harm during feeding. If the eye does not heal after two weeks, it’s time to consider alternative treatment methods.