Vision problems in dogs do not always cause visible signs that are easy to recognize, the reason for this is that dogs have the uncanny ability to compensate with their other senses. Dogs can also act stoic at times and fail to manifest in clear ways their discomfort or pain. Knowledge is ultimately power, and therefore, knowing what kind of vision problems dogs may suffer from can help you recognize potential signs of trouble so that you can get early help from your vet. Veterinarian Dr. Ivana shares a list of common vision problems in dogs.
The Top 10 Vision Problems in Dogs
Animal behaviorists tell us that all mammals use their eyes not only for seeing, but also to communicate their moods and emotions to other animals. We are magnetically drawn to a dog’s eyes, and for a good reason – they can be very expressing and revealing, and form an important part of the intimate relationship that dogs and humans share.
Although dogs cannot see as much colors as we can, their night vision is significantly better than ours. Simply put, the dogs’ eyes naturally evolved to help them track and hunt prey.
However, humans have now created many new breeds, some with distinctive eyes that require regular care and special attention. Therefore, today, eye problems are quite common among dogs.
Following are the top 10 vision problems in dogs.
- Cherry eye
Dogs have two readily visible eyelids and a third eyelid hidden in the inner corner of the eye. Inside the third eyelid there is a tear producing gland. In some dogs, the ligaments that hold the eyelid and gland in place, are congenitally weak. In such cases, the eyelid and gland pop out, thus, resembling a cherry stuck in the corner of the eye.
Because of the genetic foundation of the condition, usually both eyes are affected. The only way to treat a cherry eye is to perform a cherry eye surgery that includes re-attaching the eyelid and gland back into their normal positions.
- Corneal wounds
The clear, skin-like layer that covers the surface of the eye is called cornea. The cornea can easily be injured (cuts, punctures and ulcers). The most common cause of corneal wounds is trauma.
Dogs with abnormal eye anatomy and function are at higher risk of developing corneal wounds. Dogs with corneal wounds frequently squint because of the pain and tend to rub their paws against the affected eye. The affected eye is usually red and with excessive discharge.
The treatment for minor wounds includes eye infections prevention and pain management. Severe wounds require specific surgeries that repair the cornea and promote its healing.
- Dry eye (Keratoconjuctivits Sicca or KCS)
Tears normally consist of water, oils and mucus. Dry eye develops when the eyes stop producing the watery part of the tear mixture. Since oils and mucus are still produced, affected dogs develop a thick and yellowish eye discharge. This condition is predominantly common among Cocker Spaniels, Bulldogs, Terriers, Lhasa Apsos and Shih-Tzus.
Mild cases of KCS can be managed with artificial tears or tear production stimulating drugs. Severe cases require surgical approach. If left untreated, KCS leads to blindness.
- Pink eye (Conjuctivitis)
Conjunctiva is the membrane that covers certain parts of the eyeball, the inside of the lower and upper eyelid and both sides of the third eyelid. When the conjunctiva is inflamed, the terms conjunctivitis or pink eye are used. Pink eye in dogs is clinically manifests with reddened and swollen eyes, significant amount of eye discharge, pain and discomfort.
Rather than a disease, conjunctivitis is a symptom. This is because conjunctivitis follows many eye conditions such as infections (both bacterial and viral), physical irritations (eyelashes, dust) and allergies. The type of treatment varies depending on the exact underlying culprit.
Glaucoma is a condition that develops when fluids cannot properly drain from the eye. Over time, the fluids accumulate and start causing excessive pressure. Glaucoma is a particularly painful condition, which left untreated, can cause blindness. It is clinically manifested with redness, excessive tearing, cloudiness, dilated pupils and bulging of the eye. In a nutshell, an eye with glaucoma appears generally enlarged.
The symptoms of glaucoma can be alleviated with proper medications (that either promote decreased fluid production or increased fluid drainage). However, the only permanent treatment is surgery.
Normally, the centrally positioned lens should be clear. Sometimes, part of the lens or the entire lens can become cloudy, opaque and with a milky appearance. This cloudiness stops the light from reaching its receptors positioned in the back of the eye – thus causing either poor vision or complete blindness. The most common causes of cataracts include drug toxicity, diabetes, eye trauma and nutritional deficiencies.
Due to their similarity, cataract is often confused with lenticular sclerosis (a normal age-related change of the lens). Although rare and complicated in the past, today cataract surgeries are routinely and successfully performed.
Entropion in dogs is a condition that manifests with inward rolled eyelids. It can affect the lower, the upper or both eyelids. When the eyelids are rolled, the hairs rub the eye’s surface which initially causes pain and irritation, and eventually, leads to corneal damage. It can be congenital or acquired. The eyelids' abnormal anatomy can only be fixed through surgery.
Ectropion in dogs is a condition that manifests with outward rolled eyelids. It usually affects the lower eyelid. It is clinically manifested with a distinctively droopy eyelid, increased tear production, inflamed conjunctiva and overall eye inflammation. It is common for the signs to resolve and improve on their own and then recur without any obvious trigger. Severe ectropion cases require surgical treatment.
- Progressive retinal atrophy (PRA)
PRA is an inherited condition that causes gradually progressing blindness. It primarily affects the retina’s rods and cones – it causes premature degeneration of these light and color perceiving structures. PRA is most common in Poodles, Cocker Spainels, Border Collies, Irish Setters, Schnauzers and Norwegian Elkhounds. Sadly, there is no treatment for PRA. On the bright side, the condition is painless and over time most dogs adapt to becoming blind.
- Lens Luxation
Lens luxation is a condition that develops when the lens detaches from the fiber-like structures that are supposed to hold it in its place. It occurs in adult dogs (between 4 and 9 years) from certain breeds like German Shepherds, Cocker Spaniels, Terriers and Border Collies. The only definitive treatment for lens luxation is surgery. Until the surgery is performed, proper pain management is of imperative importance.
About the Author
Dr. Ivana Crnec is a graduate of the University Sv. Kliment Ohridski’s Faculty of Veterinary Medicine in Bitola, Republic of Macedonia.
She currently practices as a veterinarian in Bitola and is completing her postgraduate studies in the Pathology of Domestic Carnivores at the Faculty of Veterinary Medicine in Zagreb, Croatia.