Eye problems in pet may go unnoticed, especially in busy and boisterous animals. If your pet is showing any of the following symptoms, he or she may have eye problems that necessitate a visit to the vet.
Eye problems: symptoms
- Squinting or holding the eye closed (the eye is sore)
- More tearing than usual from the eye
- If the eye looks grey or cloudy
- Constantly pawing at the eye, scratching it, or seems uncomfortable
- Bulging of the eye
- Redness of the white surrounding the eye
- Bumping into things or not able to catch things as before.
Eye problems: the eye explained
To understand eye problems, it is helpful to understand how the eye works and its different components. It is a complex organ with many parts. Here are some of the basics:
• The cornea is the outermost, clear, exposed layer of the eye, the part that ‘bulges out’.
• The coloured part is a layer that is found slightly deeper, known as the iris. It can open and close thereby allowing more or less light into the eye.
• The conjunctiva is the thin pink part of the eye connecting the eyeball to the eyelids.
• The sclera is the white of the eye.
• The pupil is a circular gap in the middle of the eye, seen as a black spot. This is the part that allows light to enter and reach the back of the eye, where the retina is.
• The retina is right at the back of the eye. It is made of millions of sensitive cells that pick up light and concert it to an image that is sent to the brain for interpretation.
• The lens, which is held in its position by muscles, is completely transparent and can change shape thereby allowing the eye to focus, either near or far.
• The tear glands constantly produce a tear film across the exposed part of the eye, which is essential to keep the cells moist and feed them nutrients.
Eye problems: corneal ulcers
A corneal ulcer refers to a hole in the cornea, the central clear, outermost layer of the eye. The cornea has many nerve endings, which makes most corneal ulcers extremely sore.
What are the symptoms of corneal ulcers?
- Holding the eye closed
- Swelling of the eye
- ‘Cloudiness’ of the eye
- More tears than usual or discharge coming from the eye (often seen as crusting around the eyelids)
What causes a corneal ulcer?
Corneal ulcers can be caused by a number of different things. One of the common causes is trauma. This could be something such a scratch from another animal, or a stick or thorn from running through a bush. Eyelashes that grow in the wrong direction can also cause an ulcer. Even an eyelid growth that keeps rubbing on the same spot on the eye can cause a corneal ulcer.
Certain breeds are more prone to getting corneal ulcers. Flat-faced breeds such as Pekingese, Pugs, and Persians (known as Brachycephalics) are more prone to this condition due to the nature of their bulging eyes and the hair on their nasal folds potentially touching the cornea. Boxers are prone to corneal ulcers and eye infections that just develop with no known underlying cause. Other possibilities include chemical burns, snake venom, or any condition causing dry eyes (eg. if your pet does not sleep with its eyes closed, or dry eye syndrome where your pet’s tear glands do not produce enough tears essential to keeping cells of the cornea alive).
Get your pet to the vet
Corneal ulcers need to be treated fairly urgently, meaning you should not wait longer than 24 hours to take your pet to the vet. Without treatment, they can very quickly turn from mild ulcers that are easily treatable with medication to severe ulcers that may need general anaesthetic and surgery to save the eye.
Corneal ulcers are diagnosed by placing a drop of orange dye into the eye. This dye turns green and sticks to the ulcer in the cornea, making it easier for your vet to see.
How are corneal ulcers treated?
Most small or shallow corneal ulcers are easily treated with antibiotic eye drops. Pain killers are often also given as corneal ulcers are very painful.
Melting ulcers or deep ulcers are given that name because there is an overproduction of certain enzymes that break down the proteins that the cornea consists of. These enzymes eat away at the cornea, and once it starts, it is difficult to stop. Deeper or long standing ulcers may require general anaesthetic and surgery. If it gets to this point, your vet might suggest that you take your pet to an ophthalmology specialist as general vets do not always have the specialist equipment needed to treat these complicated ulcers.
How to administer eye drops
If you have a busy or boisterous pet, it may require more than one person to put the eye drops in the eye (one person to hold the animal still while the other applies the drops). Lift the head slightly, pull the bottom eyelid down slightly to open the eyelids, and drop the eyedrops into the eye. It is better to bring the bottle of eyedrops over the head so that they do not shy away from the eyedrops. If you have more than one type of eye drop medication to give, ensure that you leave at least five minutes between drops, otherwise the full effect of the second or third medication might be ‘washed out’ by the first.
Eye problems: Uveitis
Uveitis is inflammation of the inside of the eye. Due to the close contact between the fluid in the eye and the blood stream, many diseases that affect the body may also affect the eye. Uveitis can also occur due to trauma such as a bump to the eye, or a stick or thorn penetrating the eye. It is usually quite a painful condition.
Symptoms to look out for
- Your pet holds its eye closed
- Redness of the sclera or white of the eye
- Cloudiness to the eye
- More tears than usual coming from the eye
It is important to get to a vet if you notice any of the symptoms, as there is a chance that there may be other serious underlying conditions.
Uveitis is diagnosed by looking at the eye with an ophthalmoscope. This tool shines a light into the eye to detect the telltale signs associated with uveitis. The eye may need to be stained to look for corneal ulcers. A full examination of the animal is needed look for any other illness. Further tests such as blood or urine tests may also be needed to look for other diseases.
How is uveitis treated?
Treatment of uveitis is centres on trying to clear the inflammation in the eye and dealing with any other diseases found. Thus, a combination of eye drops and tablets may be needed to solve the problem. Cortisone, pain killers and even antibiotics may be needed.
Possible complications include:
- Permanent increase in pressure in the eye i.e. glaucoma.
- Temporary or permanent blindness.
- Other complications are possible but are uncommon.
Eye problems: glaucoma
Glaucoma occurs when the pressure in the eye increases to the point of causing damage to the eye. Most cases of glaucoma in dogs and cats are as a result of another condition. However, primary glaucoma (meaning it just happens randomly, on its own with no underlying cause) is also possible. Conditions that can cause glaucoma are:
- Lens luxation (the lens falls into the front chamber of the eye)
- Cancer of the eye
- Traumatic injury such as a hard knock to the face
- Squinting or holding the eye closed as a result of eye pain
- Redness of the whites of the eye
- Cloudiness of the eye
- Sometimes the eyeball appears bigger than normal, this is not always noticeable if the condition affects both eyes
- Complete or partial blindness is often present, but might be missed if only one eye is affected
- One eye may be affected at the start, but eventually the disease affects both
- Sometimes your pet may be somewhat depressed or ‘not themselves’
Sudden onset glaucoma is considered a medical emergency, so you need to get vet within a few hours of noticing that your pet’s eye is not normal, and if your pet seems subdued and uncomfortable.
Glaucoma is diagnosed by measuring the internal pressure of the eye. This is done with a specialised instrument and usually by an ophthalmologist.
Treatment for glaucoma
Glaucoma that appears suddenly has the best chance of responding to treatment. It is usually treated with multiple eye drops and tablets. This is all aimed at reducing the pressure with the hope of saving the eye and controlling any pain. Medication is usually lifelong.
If the sudden onset glaucoma is not treated in time it may cause permanent damage. At this stage medication may not control the pain anymore. Sometimes, the only way to control the symptoms permanently, is to surgically remove the eye.
Removing the eye: enucleation
In some instances, removal of the entire eye may be necessary. The surgery is done under general anaesthetic.
Enucleation is usually advised to relieve uncontrollable pain associated with severe eye problems. These range from glaucoma, cancer, and infection to severe trauma that has caused irreparable damage to the eye. Blindness is not usually a reason for an eye to be removed, as most eyes that have turned blind are not painful.
How will my pet cope?
The good news is that dogs and cats can quite easily adapt to life with one eye and continue to live a long, happy, and completely problem-free life.
Aside from looking a little different, you probably will not notice any major changes in behaviour, particularly if the remaining eye still has relatively normal vision. Some pets actually seem much better after the surgery as the constant pain and discomfort of a sore eye is removed. If they have not been struggling with the eye condition for a long time (for example, where the eye had to be removed as a result of sudden trauma), it may take them a few weeks to get used to only having one eye. But they usually make a complete recovery within a couple of weeks.
Although eye removal surgery may sound scary and intimidating, it can make a big difference to a pet’s overall quality of life.
In certain situations, it may be needed to remove both eyes. Or the remaining eye does not have much vision left. In this case pets may go through an adjustment phase. It is quite remarkable how well they can adjust, just like pets that have become blind.
How to care for a visually-impaired dog
- Follow post-operative care instructions.
- Give them time to adapt to their new circumstances — this usually will not take long.
- If both eyes are affected, do not make any changes to the environment. Try and keep the furniture, food and water bowls in the same place.
- Cover or fence off pools and fence any high walls that pets can fall off.
- Regular vet check-ups will also help you manage your pet’s eye health.
Article by Drs Rosali Bruggemann and Morné de Wet