Hey there, pet parents. Have you noticed your dog's eyes starting to look cloudy or bluish-gray? If so, you might be seeing a Cataract. A cataract is any opacity or cloudiness within the lens of the eye. It can be a small, insignificant spot, or it can involve the entire lens, causing blindness. Let's get a clear view of this common eye condition.
What is the Lens and What Does it Do?
The lens is a clear, disc-shaped structure that sits in the middle of the eye, right behind the iris (the colored part of the eye). Its job is to focus light onto the retina at the back of the eye, allowing for clear vision. The lens should be perfectly transparent.
What is a Cataract?
A cataract is any cloudiness that develops within the lens. This cloudiness blocks light from reaching the retina, which causes the vision to become blurry and, in severe cases, can lead to complete blindness.
It's very important to distinguish a cataract from a normal aging change called lenticular sclerosis.
- •Lenticular Sclerosis: As dogs get older, the lens naturally becomes harder and more compressed. This causes a bluish-gray, hazy appearance to the eye. This is a normal part of aging, it happens to almost all older dogs, and it does not significantly affect their vision. They can still see through it.
- •Cataract: A cataract is an actual opacity within the lens. It looks more like a white or crushed-ice appearance. A cataract does block light and affects vision.
A veterinarian can easily tell the difference between the two by looking into the eye with an ophthalmoscope.
What Causes Cataracts?
- •Heredity: This is the most common cause of cataracts in dogs. They are inherited in many breeds, including Poodles, Cocker Spaniels, and Boston Terriers. Hereditary cataracts can appear in young dogs.
- •Diabetes Mellitus: This is the second most common cause. The high blood sugar in a diabetic dog changes the metabolism of the lens, causing a very rapid formation of cataracts. Almost all diabetic dogs will develop cataracts within a year of diagnosis.
- •Old Age: Small, "senile" cataracts can form in older dogs.
- •Eye Injury or Inflammation: Trauma to the eye or chronic inflammation (uveitis) can lead to cataracts.
- •Progressive Retinal Atrophy (PRA): As we've discussed, dogs with late-stage PRA will often develop secondary cataracts.
The Stages of a Cataract
Cataracts are classified by their stage of development:
- •Incipient: A very small cataract that covers less than 15% of the lens. It does not affect vision.
- •Immature: The cataract is more significant, but you can still see the retina behind it. The dog's vision will be blurry.
- •Mature: The entire lens is opaque. The dog is blind in that eye.
- •Hypermature: The cataract has been present for a long time and is starting to break down or liquefy. This can cause significant inflammation inside the eye (lens-induced uveitis), which is painful and can lead to glaucoma.
Treatment: The Only Option is Surgery
There are no eye drops or medications that can dissolve or cure a cataract. The only treatment is surgery to remove the cloudy lens and replace it with a clear, artificial lens.
Cataract surgery in dogs is a very specialized procedure that is performed by a board-certified veterinary ophthalmologist. It is very similar to human cataract surgery. The procedure involves:
- •Making a tiny incision in the eye.
- 1Using a technique called phacoemulsification to break up the cataract with ultrasonic waves and suction it out.
- 2Placing a new, artificial intraocular lens (IOL) in its place.
Is Your Dog a Candidate for Surgery?
Before surgery, the ophthalmologist will do a full workup to make sure the dog is a good candidate. This includes bloodwork and, most importantly, an electroretinogram (ERG) to make sure the retina is still functioning. There is no point in doing cataract surgery if the retina is not working (as is the case with PRA).
Prognosis and Aftercare
The success rate for cataract surgery in dogs is very high (around 90-95%). It can restore excellent, functional vision to a blind dog.
The aftercare is very intensive. It involves giving multiple different eye drops, several times a day, for many weeks after the surgery. The dog must also wear an E-collar to prevent them from rubbing at their eyes.
For dogs that are not candidates for surgery, or for owners who decline it, the focus is on monitoring for and treating the painful inflammation (uveitis) that a mature cataract can cause.
If you notice any cloudiness in your dog's eyes, it's always best to have it checked out by your vet. They can help you determine if it's a normal aging change or a true cataract that could steal your dog's precious sight.
Sources & Further Reading:
- •American College of Veterinary Ophthalmologists - Cataracts
- 1VCA Animal Hospitals - Cataracts in Dogs