his is especially important to keep in mind in boarding and daycare environments where dogs are often playing with each other and exploring unfamiliar environments, all of which can increase the opportunity for eye irritation or injury.
Corneal ulcers are one of the more important conditions to recognize because they can deteriorate quickly. However, they are not the only cause of a painful or abnormal eye. Being able to recognize the warning signs and knowing when veterinary assessment is needed can help prevent a relatively straightforward problem from becoming much more serious.
Trauma is a common cause, including scratches from grass, branches or other objects, as well as injuries from another animal. Foreign material can become trapped against the eye, while eyelid abnormalities such as entropion can cause repeated irritation. Reduced tear production, known as keratoconjunctivitis sicca (KCS or “dry eye”), can also predispose dogs to corneal ulceration.
Some dogs are more vulnerable than others. Brachycephalic breeds are particularly prone to corneal disease because of their facial anatomy and increased exposure of the ocular surface. Research has also identified higher rates of corneal ulcerative disease in breeds including Pugs, Boxers, Shih Tzus, Cavalier King Charles Spaniels and English Bulldogs.
In some cases, an ulcer is visible as an area of surface irregularity; although, superficial ulcers can be surprisingly difficult to see without appropriate examination and fluorescein staining.
Some dogs will paw at the affected eye or rub their face against bedding, furniture or the floor. This can make the injury worse, so repeated rubbing is another useful warning sign for caretakers to notice.
Importantly, the severity of the clinical signs does not always tell us how serious the underlying problem is. A relatively small superficial ulcer can be extremely painful, while chronic ocular disease may sometimes produce less obvious signs.
Bacterial infection can develop secondarily, and, in some cases, enzymes released during infection and inflammation can cause rapid breakdown of the corneal stroma. These so-called “melting ulcers” can progress rapidly and threaten the structural integrity of the eye.
A deep ulcer can extend through much of the cornea. In severe cases, the remaining corneal tissue becomes extremely thin, creating something called a “descemetocele,” or the globe may perforate altogether. These cases are ophthalmic emergencies and may require surgical treatment to preserve the eye. For this reason, a dog that develops acute squinting, significant ocular pain, or a cloudy eye while in boarding or daycare should not simply be monitored to see whether it improves.
Conjunctivitis is common and may cause redness, discharge and increased blinking. It can occur for a variety of reasons, including irritation, infection and allergies. However, conjunctivitis and corneal ulceration can occur together, so the presence of discharge does not rule out a more significant problem.
Keratoconjunctivitis sicca (KCS or “dry eye”) can produce persistent redness and a thick, sticky discharge. The cornea may lose its normal shiny appearance and, over time, develop blood vessels, pigmentation and scarring. Dogs with KCS are also more prone to developing corneal ulcers because an inadequate tear film can compromise the health and natural protection of the cornea.
Entropion, where part of the eyelid rolls inwards, can cause hairs or facial skin to rub against the cornea. This may result in chronic irritation, inflammation and eventually ulceration.
Other ocular conditions are less common but potentially more serious. Anterior uveitis—inflammation within the front part of the eye—can cause redness, pain, squinting, light sensitivity and a constricted pupil. It may occur following trauma or as a consequence of other ocular or systemic disease.
Glaucoma is another ocular emergency. A sudden increase in intraocular pressure can cause severe pain, redness, a cloudy or blue appearance to the cornea, a dilated or poorly responsive pupil and, in some cases, sudden loss of vision. Acute glaucoma requires urgent treatment because prolonged increases in intraocular pressure can result in irreversible damage to the optic nerve.
Lens problems, including anterior lens luxation, can also present with a painful, red or cloudy eye, and may be associated with secondary glaucoma. These conditions cannot be reliably distinguished from a corneal problem simply by looking at the eye.
- Is persistently squinting or holding an eye closed
- Develops sudden or marked redness
- Has excessive tearing or new ocular discharge
- Has a cloudy, blue or unusually dull-looking cornea
- Is repeatedly pawing or rubbing at the eye
- Appears painful when the head or face is handled
- Develops a change in pupil size or shape
- Appears to have reduced vision
- Has suffered direct trauma to the eye
- Has a visible foreign body or injury involving the eye
- Develops a bulging eye or significant swelling around the eye
Sudden severe pain, apparent loss of vision, significant trauma or a markedly abnormal-looking eye should be considered an emergency. Ophthalmic emergencies require rapid assessment because some conditions can threaten vision or the integrity of the globe.
The eye should not be rubbed or examined aggressively, and staff should not attempt to remove an object that appears to be embedded in the eye. Corneal foreign bodies can be superficial or deeply embedded, and their position needs to be assessed before removal.
It is also important not to use leftover eye medication if it has been prescribed for a previous problem. In particular, corticosteroid-containing eye drops should not be used unless specifically advised by a vet, as corticosteroids can delay corneal healing and are contraindicated in an active corneal ulcer.
If a dog is already receiving prescribed eye medication, boarding staff should follow the owner’s or veterinary practice’s instructions carefully. Some ocular conditions require treatment several times a day, and missed doses can be significant.
Group play should be supervised appropriately, particularly where dogs differ substantially in size or play style. Owners should also be informed if their dog has been involved in an incident that could have resulted in facial or ocular trauma, even if the eye initially appears normal.
Brachycephalic dogs and dogs with known eye disease may need additional consideration. Their individual veterinary advice should be followed, particularly if they are already receiving eye medication or have a history of corneal ulcers.
Eyes can change quickly, and early signs are sometimes subtle. A dog that suddenly becomes reluctant to open one eye, avoids having its face touched or behaves differently during exercise may be showing signs of discomfort even when there is little obvious discharge. Recognizing these changes and knowing when to involve the veterinary team can make a big difference.
Most uncomplicated eye problems are manageable when identified promptly, but conditions such as deep corneal ulcers, glaucoma and significant ocular trauma can become serious very quickly. A careful eye check, good communication with the owner and timely veterinary assessment are an important part of keeping dogs safe during their stay.