How is Glaucoma diagnosed?

There are several tests we will perform to diagnose glaucoma; tests of vision, measurement of the intraocular pressure using a tonometer, detailed examination inside the eye and gonioscopy.

Gonioscopy allows us to look view the ‘drainage angle’ in order to identify primary closed angle glaucoma.

Some breeds of dog that are prone to glaucoma have an abnormal drainage angle and this may be of importance when deciding on a treatment course or if you are considering breeding.

Ultrasound scanning of the eye might also be needed if we are unable to see into the eye directly.

What are the clinical signs of Glaucoma?

• A cloudy or ‘blue’ appearance to the eye
• Redness of the white of the eye
• A dilated pupil that does not constrict when light is shone into the eye
• Signs of pain: sleeping more, a squinting or watering eye, being head shy or tilting the head
• Sudden blindness
• Enlarged globe

What are the causes of glaucoma?

There are two major types of glaucoma: Primary (inherited) and Secondary (acquired). In primary glaucoma the drainage system of the eye is compromised, or closing. The Secondary glaucoma is caused when another intraocular problem (cataracts, uveitis, tumours, lens luxation) is disturbing the normal outflow of the ocular fluid, leading to increased intraocular pressure.

In dogs, both primary and secondary glaucoma are common. In cats, the most common cause of glaucoma is secondary to inflammation (uveitis).

What are the treatment options for glaucoma?

Treatment will depend on a number of factors, including identification of the cause. The aim of any treatment for glaucoma is to control the intraocular pressure, alleviate the pain and preserve vision.

Depending on the cause, both eyes can be at risk of glaucoma. It is important that the other eye is assessed as soon as possible so that steps can be taken to protect its function.

In the majority of cases, patients will initially receive topical medications aimed at reducing the production of fluid and improving the outflow of fluid from the eye. If treated promptly and there is minimal damage to the optic nerve, vision can be preserved however, this is normally on a temporary basis.

Regular check-ups will be required to monitor the pressure of the eye. When/if the patient becomes less responsive to the treatment, surgical alternatives may have to be considered.

Eyes that have lost vision and continue to have increased pressure are a cause of chronic ‘migraine’ type pain for the animal. Removal of the eye is then strongly recommended to ensure the welfare and comfort of the patient.

All options will be discussed with you at your appointment.

What if my pet becomes blind?

• Coping with a blind pet can seem daunting, especially in the early days following diagnosis, but most dogs and cats adapt surprisingly well to life without vision.
• Please see our advice sheets ‘Living with a blind dog’ or ‘Living with a blind cat’ for further information and tips.