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Have you noticed something strange or different about your dog’s eyes? Perhaps they’re not opening them entirely, or you’ve had to wipe them a few more times than normal? These signs could mean they have an eye condition and need to see a veterinarian. Learn how your dog’s eyes work and how they should look so that you can spot when something is wrong quickly.
What Is The Normal Anatomy Of The Eye In A Dog?
Dogs’ eyes aren’t that different from ours. Like us, dogs have a pupil surrounded by a colored iris, and the white of the eye is called the sclera. They have an upper and lower eyelid lined with hairs like humans, but they also have a third eyelid, known as the nictitating membrane. This third eyelid folds over the eye sometimes, and you can see the inner corner of your dog’s eyes.
So, what about the parts of the eye that are internal or less visible? The transparent layer on the eye’s surface called the cornea, while the conjunctiva is the membrane that covers the eye and the inner surface of the eyelids. The conjunctiva is usually see-through, although it can become more visible when inflamed.
Within the iris, a lens is suspended by muscles known as the ciliary or intraocular muscles. The inside of the eye is separated into two main chambers. The anterior chamber is in front of the lens, and the vitreous chamber is the large area within the eyeball. The back of the eye, known as the retina, has blood vessels and surrounds the optic nerve, which leads out of the eye to the brain.
How Does Dog Vision Work?
For your dog to be able to see, light must pass through the pupil and the lens to produce an image on the retina. The iris muscles adjust the pupil’s size to regulate how much light enters the eye. The cornea and the lens can bend the light to focus the image onto the retina. The light receptors that form the retina are known as rods and cones, and they transmit signals to the optic nerve, which in turn sends a signal to the brain.
What Are The Signs That Something Might Be Wrong With Your Dog’s Eyes?
If your dog has a problem with their eyes, you might notice some of the following symptoms:
- Redness – One sign that your dog’s eyes might be inflamed is redness. You might notice that the whites of their eyes look bloodshot, or their conjunctiva or eyelids are redder than normal.
- Third Eyelid Protrusion – Your dog’s third eyelids should sit at the inner corner of their eyes without being very visible. Sometimes, if the eyes are inflamed or sore, the third eyelid protrudes further across the eye than it usually would.
- Discharge – When your dog’s eyes are healthy, they should have a tear film that keeps them moist and protects them from dust and debris. However, discharge or wetness at the inner corner of your dog’s eyes could indicate a problem. Discharge can range from clear, watery, tear overflow to thicker, yellow-green mucus or pus.
- Squinting or Blinking – If your dog’s eye is painful, you might notice them closing their eye more than usual or squinting slightly. You might also see them blinking or winking a lot.
- Sight Loss – It might seem obvious that if your dog suddenly starts bumping into things, they might have something wrong with their eyes. However, sometimes sight loss can be a bit more subtle. Dogs tend to cope very well with reduced vision in their own home or areas they know. So, you might only notice that your dog struggles in unfamiliar places or that they’re a little less confident on their evening walk when it’s getting dark.
- Head Shy – If your dog flinches when you go to stroke their head when they used to enjoy a good fuss, it could mean that their eye is painful. Even if their eyes aren’t sore, if they can’t see as well as they used to, they might not see your hand approaching and be warier.
- Cloudiness – If the surface of your dog’s eye looks a little bit cloudy, this could be a sign of a problem. A few conditions can cause the eye to look white or cloudy, ranging from corneal ulceration to cataracts.
- Eye Rubbing – If your dog is pawing at their face or rubbing their eye against the furniture, it could mean that their eye is itchy or sore. Sometimes, you won’t see your dog rubbing their eyes, but you’ll notice that the skin around the eye is bald, has thinning fur, or is inflamed.
What Are The Common Eye Conditions In Dogs?
Here are some of the most common dog eye conditions:
Conjunctivitis is inflammation of the conjunctival layer of the eye’s surface. It’s usually caused by infection, trauma, or allergies. Symptoms include discharge, redness, and squinting, and your dog might be showing signs of pain and irritation. Conjunctivitis is typically treated with medicated eye drops containing an antibiotic and an anti-inflammatory.
A cornea ulcer is damage to the surface layer of your dog’s eye. This can occur due to trauma like rubbing or a cat scratch, but dogs with poor tear production can also get corneal ulcers. Corneal ulcers can become quite deep, and in severe cases, the eye can be at risk of rupture. Symptoms of corneal ulcers are the same as conjunctivitis. However, the discomfort may be more prominent. Treatment for corneal ulcers includes antibiotic, anti-inflammatory, and lubricating eye drops. In some cases, your veterinarian might also need to perform a minor operation to help the eye heal.
It’s not uncommon for dogs to get foreign material in their eyes, causing pain and sometimes infection. Some possible eye foreign bodies include thorns and grass seeds. You might not be able to see the foreign material itself, but you might notice that your dog has discharge from their eye and is shutting it more than expected. The eye might also look red and inflamed. Your veterinarian may need to apply some local anesthetic or give sedation to allow them to remove the foreign material.
Distichiasis is the growth of extra eyelashes on the eyelid margin. These hairs rub against the eye surface, causing irritation and inflammation. It often happens in young dogs, although older dogs can also be affected. Again, symptoms include discharge, squinting, and redness. Frustratingly, although the hairs can be plucked, they often grow back. Therefore, a combination of electrolysis and surgically removing the hair follicles are often used.
A cherry eye is when the nictitans gland (a gland that produces tears) prolapses and protrudes from the third eyelid. If your dog has a cherry eye, you’ll notice a bulge of pink tissue in the inner corner of their eye. In milder cases, the gland might pop in and out, but often the gland remains prolapsed. Your veterinarian can operate to replace the gland in the third eyelid. Still, even after surgery, a cherry eye can occasionally recur.
Keratoconjunctivitis Sicca (Dry Eye)
Dry eye occurs when the tear glands don’t produce enough tears and is common in certain breeds, including Cavalier King Charles spaniels. The tear film is vital for keeping your dog’s eye healthy and comfortable. Your dog might experience corneal ulceration or conjunctivitis without an adequate tear film. Dry eye can be treated with artificial tears or lubricating eye drops, but sometimes an immunosuppressant is required to prevent the destruction of the tear glands.
Uveitis is inflammation of the iris, but sometimes the deeper tissues of the eye are also affected. The inflammation can lead to an increase in pressure within the eye, causing glaucoma. The symptoms of uveitis include severe pain, squinting, redness, and a constricted pupil. Your dog might avoid bright lights, and the eye might seem cloudy. Uveitis causes many causes, including trauma, toxins, infections, eye tumors, cataracts, and high blood pressure. Depending on the cause, the treatment will vary. Although many types of uveitis are treatable with eye drops and pain relief, the eye has to be surgically removed in other cases.
Glaucoma is when the pressure inside the eye increases, either due to uveitis, lens movement, tumors, or changes in the fluid production and drainage in the eye. Glaucoma is an excruciating condition, but aside from signs of pain, your dog’s eye looks like it’s bulging a bit, or you might notice signs of sight loss. With quick intervention, some types of glaucoma can be treated with eye drops to reduce the pressure, and sight can be preserved. However, many cases eventually require surgery to remove the eye.
Just like their humans, our canine companions can get cataracts too. A cataract is when the lens becomes firmer and less transparent. As the cataract matures, it blocks more and more light from reaching the back of the eye until vision is lost. Cataracts are often inherited but can also be due to diabetes or trauma. Although many dogs cope well with cataracts, specialist surgery can remove them and restore vision.
Nuclear sclerosis is often mistaken for cataracts and refers to the gradual clouding of your dog’s eyes, often with a bluish tinge. This is due to age-related changes within the lens and doesn’t usually affect your dog’s ability to see.
When To See A Vet
It’s best to get your dog checked by a veterinarian if they show any of the above symptoms. Many eye conditions are very painful, and some can lead to sight loss without prompt treatment. With so much overlap in symptoms, it’s hard to ensure that your dog’s eye issue isn’t severe. Your veterinarian can perform a thorough eye examination, use specialist instruments, and perform any necessary tests to make a diagnosis.
Treating Eye Issues Before It’s Too Late
Many different eye conditions could affect your dog, and some can be serious and very painful. Therefore, it’s a good idea to familiarise yourself with the symptoms to recognize any problems quickly. After all, prompt treatment can make all the difference regarding the eyes. Keep a dog’s eyes clean with tear stain wipes and protect them with dog goggles.