Last Saturday, March 12th was World Glaucoma Day Did you know that Glaucoma is one of the main causes of blindness in dogs? In order to raise awareness about this disease, which is one of the most common ocular emergencies in small animal clinics, we explain below 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 outflow of aqueous humor, causing it to accumulate inside the eye and thus increasing the intraocular pressure (IOP). Once the IOP increases, the retinal ganglion cells will be progressively damaged leading to their apoptosis and a neuritis of the optic nerve will be generated, which may lead to the patient’s loss of vision. The patient’s prognosis is usually reserved, with most of them being able to lose the sight of both eyes progressively and even, in some cases, reaching the enucleation of the affected eyes.
There are different classifications of glaucomas:
According to their evolution we can classify them as acute or chronic.
According to the cause, we can differentiate between:
Congenital
Primary: usually linked to hereditary factors. It is the most common in dogs.
Secondary to other intraocular pathologies. Most commonly in cats.
Depending on the morphology of the iridocorneal angle, they may be:
Open angle: it is the most common in humans. In dogs, there are some predisposed breeds, such as the Beagle or the Norweigan Elkhound.
Narrow angle
Closed angle: It is the most common type in dogs. The most predisposed breeds are American and English Cocker Spaniel, Basset Hound, Chihuahua, Great Dane, Labrador Retriever, Chow-Chow, Shar-pei, etc. as we showed you previously in our social networks (Linkedin, Instagram).
In the initial stages when IOP is slightly elevated, the symptoms usually go unnoticed, but they will progress until IOP is markedly elevated and then the patient may present: severe pain, red eyes, photophobia (intolerance to light), epiphora (excessive and constant tearing), mydriasis (pupil dilation), etc.
To reach the diagnosis we will have to be attentive to the patient’s anamnesis and clinical history, perform a general and ophthalmoscopic examination, measure IOP by tonometry (there is a great variety of different tonometers on the market) and evaluate the morphology of the iridocorneal angle by gonioscopy. In some cases the patient may undergo other tests such as high-resolution ultrasound.
Various types of medical (topical or systemic) or surgical treatments (such as the different techniques of cyclodestructive laser surgery) can be used in an attempt to reduce IOP. Another important asset in the treatment of glaucoma to try to delay the patient’s vision loss as much as possible, either in both eyes if the diagnosis is early or in at least one of the two, when sight has already been lost in one, is supplementation with nutraceuticals such as Glauco, rich in B vitamins and other antioxidant and neuroprotective substances such as Ginkgo Biloba or wild blueberry, to help reduce the progression of the disease by protecting the retina and N. Optic from damaging free radicals due to increased oxidative stress and by increasing blood flow to the optic nerve.
In conclusion, the more information and knowledge we have about glaucoma and the earlier diagnosis can be made when vision is still preserved, the greater the chance that treatment options will be more effective and thus reduce damage to the retina and optic nerve, improving the quality of life of affected dogs.
