Congenital Ocular Anomalies in Dogs: A Complete Guide
As dog owners, we all hope for our furry friends to be healthy and happy. However, some dogs are born with eye abnormalities that can cause discomfort, affect their vision, or even lead to blindness if left untreated.
In this article, we will discuss the different congenital ocular anomalies that dogs can suffer from, their causes, symptoms, and available treatments. Genetic Causes:
Persistent Pupillary Membrane
Persistent Pupillary Membrane (PPM) is a condition where a part of the tissue remaining from the fetal development covers the eye’s pupil. The membrane can cause variable iris defects, cataracts, and colobomas of the uvea, leading to vision problems and discomfort for the dog.
PPM is an inherited condition and is commonly seen in breeds like the Australian Cattle Dog, Border Collie, and Siberian Husky.
Multifocal Retinal Dysplasia
Multifocal Retinal Dysplasia is a condition where the retina has small, irregularly shaped folds. This causes vision problems like blindness, and the condition is often seen in Beagles, Labrador Retrievers, and Doberman Pinschers.
Collie Eye Anomaly
Collie Eye Anomaly (CEA) is an inherited condition commonly found in breeds like Collies and Shetland Sheepdogs. It causes abnormalities in the eye’s structures, including the retina, choroid, and sclera.
The condition can cause retinal detachment, cataracts, and even lead to blindness.
Photoreceptor Dysplasia
Photoreceptor Dysplasia is a condition where the layers of the retina are not formed correctly, causing vision problems and blindness. It is inherited in certain breeds like the Miniature Schnauzer and Toy Poodle.
Corneal Opacities and Cataracts
Corneal Opacities and Cataracts are conditions that affect the dog’s vision, causing cloudiness in the eye’s lens. These conditions can be inherited or caused by other factors like injury, toxins, or nutrition deficiencies.
Retinal Detachment
Retinal detachment happens when the inner layer of the eye separates from the outer layer. It can be caused by trauma or secondary to other eye conditions like PPM or CEA.
Spontaneous Malformations and Uterine Conditions:
Colobomas of the Lid
Colobomas of the Lid happen when there is a notch or missing tissue on the dog’s eyelid. It can cause eyelid twitching and watery eyes but generally has no significant effect on vision.
Colobomas of the Iris
Colobomas of the Iris is a condition where the iris is misshapen, causing sensitivity to bright lights. It usually doesn’t affect vision unless it is associated with other ocular anomalies.
Dermoids
Dermoids are tumor-like cysts that form in the eyelid that can cause eyelid twitching and watery eyes.
Dermoids are not common, and when observed, they require prompt veterinary examination.
Iris Cysts
Iris cysts occur when fluid-filled sacs form on the iris. They are not visible to the naked eye, but they may cause slight bulging of the iris or interfere with the dog’s field of vision.
Congenital Glaucoma with Buphthalmos
Congenital Glaucoma with Buphthalmos is an inherited condition that affects certain breeds like the Basset Hound and Dalmatian. It causes a painful red eye, tearing, and an enlarged eye.
If left untreated, the condition can lead to blindness. Optic Nerve Underdevelopment, Rod-Cone Malformation, and Cone Malformation
These conditions affect the dog’s vision and can cause blindness.
They are separately inherited and seen in various dog breeds. Other Risk Factors:
Exposure to Toxic Compounds
Exposure to toxins like pesticides and heavy metals can cause developmental abnormalities in the fetus and lead to ocular anomalies.
Lack of Nutrients
Lack of proper nutrition during pregnancy can cause developmental delays and the formation of ocular anomalies in puppies.
Systemic Infections and Inflammations During Pregnancy
Infections and inflammations during pregnancy can damage the developing fetus and cause ocular anomalies. It is essential to keep in mind that not all dogs with congenital ocular anomalies require treatment.
Some of the conditions might not pose a severe threat to the dog’s health, while others can be managed with appropriate medication. However, some conditions like retinal detachment or glaucoma require urgent veterinary attention, and delaying treatment can lead to irreversible vision loss.
In conclusion, congenital ocular anomalies are relatively common in dogs and can affect their overall well-being. Knowing the signs, symptoms, and possible underlying causes is crucial in ensuring prompt and proper treatment.
If you suspect that your dog has an ocular anomaly, it is essential to seek veterinary care immediately for diagnosis and treatment. With proper care, dogs with congenital ocular anomalies can have a good quality of life and enjoy the world around them.
Diagnosis of Congenital Ocular Anomalies
Diagnosing congenital ocular anomalies in dogs requires a thorough medical history and an eye examination from a qualified veterinary ophthalmologist. In this section, we will discuss the methods used to diagnose congenital ocular anomalies in dogs.
Medical History
During the medical history, the veterinarian will inquire about the dog’s development and environment after birth, including any in utero conditions that may have impacted the pup’s development. The veterinarian will also ask about any symptoms that the dog is experiencing and family history of ocular anomalies.
Eye Health Test
Several tests can be used to diagnose congenital ocular anomalies. The Schirmer Tear Test is used to evaluate tear production and diagnose dry eye, which can occur in dogs with Congenital Keratoconjunctivitis Sicca (KCS).
The tonometer is used to measure the dog’s internal eye pressure, which can be useful in diagnosing glaucoma. The indirect ophthalmoscope and the slitlamp biomicroscope are used to view the interior of the eye to detect any abnormalities, including the presence of cataracts.
These tests are crucial in detecting abnormalities in the retina, choroid, and optic nerve.(1)
Ultrasound
An ultrasound can also be used to evaluate the internal structures of the eye, such as the lens, vitreous humor, and retina. This non-invasive imaging technique can detect abnormalities such as lens luxation, vitreous degeneration, and the presence of iris cysts.
Ultrasound can also be used for progress monitoring of certain conditions like multifocal retinal dysplasia, where retinal layers are not formed correctly.
Ultrasound also reveals the dog’s disease state before the eye surgery.(2)
Angiography
Angiography is another diagnostic tool used to view problems in the posterior (back) of the eye. This test involves injecting a dye into the bloodstream, and then the vet examines the eyes using specialised imaging techniques such as fluorescein angiography.
This test allows the veterinary ophthalmologist to identify any abnormalities in the retina’s blood vessels, such as CEA and PPM, which may lead to retinal detachment.(1)
Treatment of Congenital Ocular Anomalies
The treatment of congenital ocular anomalies often depends on the type of anomaly and the dog’s overall health. Some conditions may not require treatment, while others will require surgery, medication, or lifelong management.
Surgery
Surgical repair is an option for dogs with some congenital eye birth defects and helps restore the dog’s vision. For example, puppies with a coloboma can undergo a surgical procedure to correct the eyelid’s position and restore normal eye function.
Lens extraction, corneal repair, and retinal reattachment surgeries are also available to treat congenital anomalies.(2)
Medication
Medicines can help manage some congenital ocular anomalies in dogs. For KCS, affects a dog’s tear production and causes dry eyes, an eye lubricant like artificial tears can be applied regularly to the afflicted dog’s eyes to relieve discomfort.
Antibiotics are also useful in treating KCS. Mydriatics are used to induce dilation of the pupils for dog breeds with congenital cataracts, which improves their vision somewhat.
Treatments require close monitoring and expert consultation.(3)
Management of Progress
Dogs living with congenital ocular anomalies often require careful management to maintain their eye health and ensure their vision is the best it can be. Owners of dogs with congenital anomalies should visit their veterinarian for check-up appointments twice yearly.
Progress monitoring includes observation of the dog’s tear production and changes in the dog’s eye structure. Special adaptations can be made to improve the dog’s quality of lifefor example, bright light avoidance for dogs with PPM and photoreceptor dysplasia.(2)
Restricting Breeding
Diagnosis and prevention of ocular anomalies through selective breeding play a significant role in reducing the prevalence of these congenital defects. For breeds predisposed to ocular anomalies, tests such as the Canine Eye Registration Foundation (CERF) help clinicians determine if an anomaly is present.
Preventing the breeding of dogs with ocular defects can reduce the recurrence of the defects in the breed.(3)
Conclusion
Diagnosing and treating congenital ocular anomalies in dogs is crucial in preserving their overall well-being. Regular veterinary check-ups, tailored medication, and when needed, surgical interventions significantly improve the dog’s ability to see and reduces discomfort.
Preventative measures, such as controlling toxin exposure and breeding selection, remain the most effective means of managing congenital ocular anomalies. With the help of veterinary professionals and pet owners’ care, dogs living with congenital ocular anomalies can lead healthy and happy lives.
Congenital ocular anomalies are relatively common in dogs, and diagnosis and treatment are essential in preserving their overall health and well-being. Medical history and eye health tests, ultrasound, and angiography are useful tools for diagnosing some congenital eye birth defects.
For treatment, veterinary ophthalmologists may suggest surgery, medication, or lifelong management. Preventative measures such as selective breeding and reducing exposure to toxins are effective in minimizing the prevalence of ocular congenital defects.
It is crucial to seek veterinary care immediately if you suspect that your dog has an ocular anomaly. With proper care, dogs with congenital ocular anomalies can still live healthy and happy lives.