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Do You See What I See?

Ask the Ophthalmologist: Cataracts in Dogs
By Dr. Cory Mosunic, DVM | Jun 02, 2020

What is a cataract?

A cataract is any opacity of the lens within the eye. The lens is normally a clear structure within the eye that help bring objects into focus. It can be a small cataract (incipient) and not interfere with vision, or it can be larger and interfere with vision. There are also aging changes that can occur in the lens of older dogs which are not cataracts but often can be mistaken as cataracts. This condition is called nuclear sclerosis and usually does not interfere with vision.

Why do cataracts form?

Cataracts can occur for my many reasons. Dogs can develop cataracts at a very young age (congenital), or they can form due to an inherited disease and develop later in life. Cataracts often occur secondarily to diabetes and sometimes after traumatic events to the eye.

Can cataracts be treated?

Yes, a surgical procedure can often be performed to remove the cataracts. This procedure is called phacoemulsification. This is the identical procedure which is used to remove cataracts in humans, but unlike in humans, it is performed under general anesthesia. This procedure is performed with the assistance of a surgical microscope. A special instrument is placed through a small incision in the eye and high frequency ultrasound is used to break up and aspirate away the cataract lens material. There are no topical medical treatments that can remove cataracts.

How well are pets able to see after surgery?

Vision is restored immediately after surgery and continues to improve over the first weeks postoperatively. It is so rewarding to observe patients regain their vision and confidence after surgery. Additionally, some patients are candidates for a “replacement lens” or “false lens”, which provides clearer vision especially for objects “close up”.

Are there any complications?

Typically, cataract surgery has a 95% or better success rate, however there are some complications that can occur and need to be recognized. The most common postoperative complications are intense inflammation (uveitis), infection, glaucoma, and retinal detachments. Typically, these postoperative complications are minimized with early surgical and medical intervention after cataracts are diagnosed.

How do I know if my pet has cataracts or is a candidate for surgery?

If cataract or vision difficulties are suspected, it is best to have a complete ophthalmic examination performed. If cataracts are diagnosed, consultation with a board certified ophthalmologist is recommend. The ophthalmologist will be able to address candidacy for surgery or recommend other types of treatment. Typically, your pet will receive topical eye medications at this exam to start treating the inflammation that already exists within the eye caused by the development of the cataracts. Prior to surgery, testing of the retinal health would be performed. This testing consists of an ERG (electroretinogram) and ocular ultrasound. These are non-painful tests that are performed to test the health of the retina to ensure that when the cataracts are removed that the retinas are healthy so that vision will be restored after surgery.

What if my pet is unable to receive surgery?

It is still very important to have your pet’s cataracts evaluated even if you do not plan on pursuing surgical removal. The development of cataracts within the eye can cause intense inflammation (lens induced uveitis) which should be treated with topical eye medications to hopefully prevent other potentially painful complications such as glaucoma or retinal detachment. These complications are why it is better to perform cataract surgery early in its development rather than waiting until the cataract matures or ‘ripens’.

 

Dr. Cory Mosunic, DVM

Board-certified Ophthalmologist

Portland Veterinary Emergency and Specialty Care