The Key Points of Glaucoma

Last Saturday, March the 12th was World’s Glaucoma Day. Did you know that Glaucoma is one of the main causes of blindness in dogs? In order to increase the awareness and knowledge of this disease that is one of the most common ocular emergencies in the small animal practice, we’ll explain the key points of the pathology.

Glaucoma is a chronic neurodegenerative disease of the Optic Nerve and retina. It is characterized by an alteration in the balance between the production and the output of the aqueous humor, leading to its accumulation inside the eye and thus, an increase of the intraocular pressure (IOP). The consequences of the IOP increase are the progressive damage of the retinal Ganglion Cells leading to their apoptosis and the neuritis of the Optic Nerve that may lead to the loss of the patient's vision. The patient's prognosis is usually reserved, with most of them losing both eyes sight progressively and even in some cases, leaving the veterinarian with no other solution but the enucleation of the affected eye/s.

Glaucoma can be classified in the following different ways:

  • According to their evolution, we can classify them as acute or chronic.
  • Depending on the cause, we can differentiate them between:
    • Congenital
    • Primary: usually linked to hereditary factors. It is the most common in dogs.
    • Secondary to other intraocular pathologies. Most common in cats.
  • Depending on the morphology of the iridocorneal angle, they might be of:
    • Open angle: it is the most common in humans. There are some predisposed breeds, such as Beagle or Norweigan Elkhound.
    • Narrow angle
    • Closed angle: It is the most common kind in dogs. Some predisposed breeds are American and English Cocker Spaniel, Basset Hound, Chihuahua, Great Dane, Labrador Retriever, Chow-Chow, Shar-pei, etc. just as we already informed you some time ago in our social networks (Linkedin, Instagram).
In the most initial phases when the IOP is lightly elevated, the symptoms usually go unnoticed by the owners, but they will progress until the IOP is markedly elevated and in that moment the patient will present all or some of the following symptoms: severe pain, reddened eyes, photophobia (intolerance to light), epiphora (excessive and constant tearing), mydriasis (pupil dilation), etc.

To reach its diagnosis the veterinarians will have to look at the patient’s clinical history, perform a general and ophthalmological examination, measurement of IOP by tonometry (there is a variety of different ones in the market) and evaluate the morphology of the iridocorneal angle with gonioscopy. In some cases, other techniques such as high-resolution ultrasound may also be performed.

Various types of treatments, both medical (topical or systemic) and surgical (such as the different techniques of laser cyclodestructive surgery) can be used to try to reduce the IOP. Another key asset in the treatment of glaucoma to try to delay as much as possible the loss of the patient's vision, either in both eyes in early diagnosis or at least one of the two, when the vision has already been lost in one, will be the supplementation with nutraceuticals such as Glauco, rich in B group vitamins and other antioxidant and neuroprotective substances such as Ginkgo Biloba or wild blueberry, to help reduce the progression of the disease and then, protect the retina and the Optic Nerve from damaging free radicals due to increased oxidative stress and increase blood flow to the Optic Nerve.

In conclusion, the more information and knowledge we have about glaucoma and the earlier it is diagnosed, and the vision of both or at least one of the two eyes is preserved, the greater the opportunity for the treatment options to be more effective, reducing then the damage to the retina and Optic Nerve and improving the dog’s quality of life.

Why some dog breeds are more predisposed to develop ocular pathologies?

In the recent months, and especially after Danika Bannasch et al.’s publishment in December in the journal Canine Medicine and Genetics, inbreeding in canine breeds has become lately the main topic in the animal health media. Inbreeding means having a high kinship between one and/or different specimens. You may be wondering the relationship between this study and the predisposition of some canine breeds to develop ocular pathologies, right? Keep reading to get to know how these two matters are related.

Unlike production animals, breed dogs are selected based on their pedigree and phenotypic characters or physical appearance. The pedigree or genealogical tree is insufficient as it does not include a significant number of individuals; while being selected according to the characters or the appearance traits, ends up having an impact on the animal’s functional and/or vital characteristics. The Bannash et al. study, using the Wisdom Health Genetics database, estimated an inbreeding average of 25% in 227 breeds. A high inbreeding is significant to develop certain diseases. In addition to the inbreeding problem, the pet’s life quality has improved, which implies that, as in humans, developing degenerative problems associated to age.

Some breeds-disease associations are well known, such as hip dysplasia in Golden Retrievers or heart failure in brachiocephalic. Even so, we always forget about those that concern the sight, which besides of being extremely annoying, they can end up having huge repercussions on the animal's health. That is why the last month we made several publications on our social media (LinkedIn and Instagram) presenting our ophthalmological line related to canines (and felines, less frequent) predisposed to develop ophthalmological pathologies. We have relied on the BVA (British Veterinary Association) and The Kennel Club study . Please find forward the links to get to know the predisposed breeds to each disease:

Age related or genetically predisposed degenerations have a reduced treatment option. Supportive treatments that slow the onset and/or relieve symptoms are often the only solution. PREVENTION IS THE KEY.

Please find forward the following link if you want to check out the diseases, regardless the ophthalmic ones, that is predisposed to develop each dog breed.