Eye Conditions

Management

1. The usual presentation is a dog with a blind, painful eye. We need to treat this eye and make it comfortable.

2. Treatment is given to the good eye to delay glaucoma developing if it is predisposed to glaucoma.

3. This condition may get worse, even with the correct treatment. Drops and tablets seem to work extremely well in humans, but are rarely effective in dogs.

4. Surgery is usually required to control glaucoma, in some cases we can use drops in to the eye once daily. With time we find that some glaucoma cases are not as well controlled with the drops, and surgery may then be required. The management of glaucoma depends on whether or not the eye is still visual or has a chance to regain vision.

Potentially visual eyes

To save vision we use a state of the art Diode Laser to destroy some of the fluid producing cells inside the eye. This is what is commonly done in humans that no longer respond to medications. We generally monitor the patients intraocular pressure frequently over the next few days depending on the pressure readings..

For blind eyes it is important to treat the glaucoma to try and reduce the pain inside the eye. For blind, enlarged eyes we recommend an Intrascleral Prosthesis. For blind eyes that are not enlarged we can laser to control the glaucoma.

Prevention

We can check to see if an eye is predisposed to glaucoma by examining the drainage angle with a special contact lens. This is called Gonioscopy. If the drainage angle is malformed then there is a greater risk of glaucoma developing in the eye. If an eye is predisposed to glaucoma, then lifetime treatment with drops is required. However, even with diligent use of drops it is possible for the eye to develop glaucoma. Prompt recognition and treatment of the glaucoma are essential to save vision.

The early signs of glaucoma

1. Redness of the white of the eye

2. Blue, hazy eye

3. Dilated pupil that will not become smaller when a bright light e.g. penlight, is shone into the eye.

Info For Vets

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Why Check The Retina

Why Do We Check The Retina?
The retina (the nerve tissue at the back of the eye) must be healthy for cataract surgery to restore vision. Many purebred dogs such as Labradors, Australian Cattle Dogs, Australian and Silky Terriers, Poodles, and Cocker Spaniels can have PRA: progressive retinal atrophy. This is the cause of the poor vision and the cataracts. PRA in the early stages can cause poor night vision, followed by poor day vision and eventually cataracts. In many cases the early signs of PRA are overlooked, even by the most diligent of owners, and it is assumed that the cataracts are the cause of the vision loss. In these cases the dog is blind because of the PRA, so cataract surgery will not restore vision.

Electroretinography

If we cannot see the retina because the cataract is too cloudy, an ERG (electroretinogram) will be performed. This is an electrical test of the retina performed under light anaesthesia. Using a computer we measure the electrical response to bright lights being flashed into the eye. If the retina is healthy the ERG will show a normal wave pattern; if the retina is diseased with PRA the ERG is flat. If the ERG shows that the retina is not working, then cataract surgery will not help to improve vision The ERG will not show early retinal detachments. As part of the general workup before surgery we may perform ocular ultrasonography. This is usually done at the same time as the ERG. The ultrasound is used to image the inside of the eye; in these cases we are checking to make sure that the eye is healthy enough for surgery. In particular we are looking for advanced degenerations.

Inflammation

What Is Cataract / Lens Induced Uveitis (Inflammation)?
As cataracts form, the lens protein inside the eye changes. This change may allow the lens protein to leak into the inside of the eye. This causes inflammation inside the eye, and this must be treated. Diabetic dogs seem to be especially prone to this inflammation. Lens induced uveitis can cause painful outcomes such as glaucoma and/or lens luxation. Pre-operative lens induced uveitis can lower the success rate of cataract surgery. Lens induced uveitis can be controlled in most cases with longterm drops (Pred Forte or Maxidex) and in some cases tablets. Surgery is helpful in most cases to help control the lens induced uveitis as the protein that is causing the reaction is removed. The cataracts that develop because of the PRA will often cause this lens-induced uveitis. Watch for signs of redness on the whites of the eye. If treated early, painful outcomes such as glaucoma and lens luxation can be avoided.

Treatment

What Is The Treatment For Cataracts?
Surgery is the only effective method to remove the cloudy lens from the eye. There are no known preventative treatments for cataracts. From time to time various drops, lotions, pills, and special diets have been suggested to help with cataracts. These have not been proven to help dissolve or reduce a cataract.

Cataract Surgery Information1.11 MB

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