Corneal damage is common in dogs and cats.  The cornea is a very thin, transparent layer of tissue that forms the front part of the eyeball.  The eyelids protect the cornea, and the tear film nourishes the cornea and keeps it moist.  The cornea can become damaged by an eye infection, foreign objects (such as sand or splinters), dry eye, or trauma (such as being scratched).  Dogs and cats with “pushed-in” faces and bulging eyes are especially at risk.

When the cornea is damaged in any way, it is very painful.  Your pet may hold its eye closed, blink excessively, or rub or paw at the eye.  Often damage is secondary to an eye infection, and the eyes may appear red and watery.  Without treatment, the cornea can scar as blood vessels enter the area to repair the damage.  Such scars can show up as dark spots on the cornea that decrease transparency and possibly reduce vision.

Your veterinarian will perform a thorough eye examination, including looking for signs of corneal damage.  A special dye called fluorescein is used to cover the surface of the eyeball.  After the excess dye is washed away, any nicks, tears, scrapes, scratches, or ulcers on the cornea retain some of the dye and are stained a bright greenish or orangish color.

Treatment for corneal damage includes antibiotic eye drops and sometimes eye drops to dilate the pupil and ease painful spasms.  Topical corticosteroids are generally not used because they can interfere with healing.  In severe cases, your veterinarian may sew the eyelids closed temporarily to protect the damaged area so it can heal.  With proper treatment, corneal damage usually heals rapidly without permanent scarring or vision problems.

Q&A

What is the cornea and how does it become damaged?

The cornea is a very thin, transparent layer of tissue that forms the front part of the eyeball.  The cornea can become damaged by an eye infection, foreign objects (such as sand or splinters), dry eye, or trauma (such as being scratched).  

How is corneal damage diagnosed?

Your vet will instill a special dye called fluorescein to look for nicks or ulcers on the cornea.  This dye covers the eyeball and is then washed away, leaving behind a bright greenish or orangish color that marks the location of any tears, scrapes, scratches, or ulcers on the corneal surface.

How are corneal ulcers treated?

Treatment for corneal damage includes antibiotic eye drops and sometimes eye drops that dilate the pupil to ease painful spasms.  In severe cases, your veterinarian may sew the eyelids closed temporarily to protect the damaged area so it can heal.  

Written and reviewed by John A. Bukowski, DVM, MPH, PhD
and Susan E. Aiello, DVM, ELS