Not all cataracts require surgery. Very small cataracts, or incipient cataracts, are difficult to find without magnification. They take up less than 15% of the lens and so they may not affect vision as much as an immature cataract (more than 15% of the lens is affected but the retina is still visible) or a mature cataract, which takes up the entire lens1. Cataracts can greatly impair vision and can cause inflammation within the eye that can progress to glaucoma, which can be painful. Sometimes medicated anti-inflammatory eye drops can help cataract sufferers, but with advanced cataracts, surgical removal is recommended.
Ophthalmologists need to check if the dog’s retina is healthy in order to determine if they will be a good candidate for cataract surgery. This kind of surgery will not restore vision if the retina is damaged. Two kinds of tests are performed: an eye ultrasound exam and an electroretinogram (ERG), which looks at the electrical activity of the retina, like how an EKG looks at the electrical activity of the heart.
Cataract surgery for dogs is performed under general anesthesia because the eye needs to perfectly still for the procedure. A small incision is made into the eye, and then an ultrasonic handpiece is inserted into the incision. The handpiece is roughly the size of a ballpoint pen. It is used to break the cataract into pieces and then remove them from inside of the eye. This technique is called phacoemulsification.
Once the cataract fragments are removed, an artificial lens is then implanted inside of the eye and the incision is sutured closed. Cataract surgery is often performed on an outpatient basis, and so it is likely that the patient will go home on the same day. Most cataract surgeries have a 95% success rate, and the majority have their vision restored almost immediately3.