Corneal Ulcer

Corneal Ulcer/Erosion

By Dr. Karen Burgess

What is a corneal ulcer?
The cornea is the clear surface of the eye (where a contact lens is placed in humans). This window to the eye contains several very thin layers of cells. A corneal abrasion or erosion occurs when the most superficial layer of cells (epithelial cells) are damaged. Lesions that affect the epithelium and the deeper stroma are called corneal ulcers. If the final and deepest layer of the cornea (Descemet’s membrane) of the cornea is also affected permanent loss of vision and collapse of the eye may occur.

What causes corneal ulcers?
Corneal ulcers are typically caused by external trauma, foreign bodies, chemical irritants such as shampoo, or self-inflicted trauma (example pet scratching or rubbing eye). Some breeds are also predisposed to decreased tear production which can dry out the cornea leading to erosions.

What are symptoms of corneal erosions/ulcers?
Corneal lesions are usually very painful. In an effort to relieve associated itchiness and discomfort, pets will often rub the affected eye against the ground, against furniture, or with their paws. The eye will often be held closed, be more sensitive to light, and appear red. Drainage may also be present.

How do you test for a corneal ulcer?
Your veterinarian will apply a fluorescein stain (eye drop) that will effectively highlight any damage to the cornea. Testing for adequate tear production may also be performed.

What is the treatment for corneal ulcers?
The severity of the corneal lesion will determine treatment. In severe cases referral to an ophthalmologist may be necessary for surgery in an attempt to save vision. In milder cases topical eye medications, lubricants, and pain medicine may be prescribed. Atropine drops may also be used to dilate the eye thus helping with discomfort. If atropine is prescribed the dilation will last for several days beyond treatment and will cause light sensitivity. An Elizabethean collar will also be necessary to help prevent any further self-trauma to the eye. In uncomplicated cases the cornea will tend to heal in just a few days. A recheck of the eye should be performed two to three days after initiation of treatment to ensure improvement. Be aware that pets may taste any medications applied to the eye due to tear ducts which drain into the mouth. This may cause drooling or pawing at the mouth after eye medication application. Topical anesthetics are not recommended to treat ulcers as they can hinder healing. If your pet is more uncomfortable after application of eye meds, contact your veterinarian; in some situations a pet may be sensitive to a particular product.