Recently, a friend in an online community adopted a three-year-old Jack Russell Terrier named Biggles. She is his third owner! Like many JRTs, Biggles is feisty and active; he’s also nearly blind from cataracts.
Eye disorders, especially cataracts, are common to the Jack Russell Terrier. A cataract is the loss of normal transparency of the eye lens. Any spot on the eye that is not clear can be considered a cataract; some are too small to see with the naked eye but others are quite visible and appear as milky or white spots.
Cataracts in Jack Russell Terriers seem to be hereditary, a trait of the breed. However, cataracts can also be caused by things like eye injuries, exposure to great heat, diabetes, and even simple old age.
Cataracts can be treated in JRTs if the retina is not damaged. The lens is removed and if necessary, replaced. However, a dog suffering from progressive retinal degeneration (PRD) or atrophy (PRA) may not be able to have surgery for their cataracts.
PRD/PRA is a slow death of the tissue that forms the retina, and is easily overlooked because of its slow progression. Your first indication of a problem may be that your dog seems to be reluctant to go outside at night or has trouble navigating a dark room. After the night vision disappears, the day vision will follow.
If you have a Jack Russell who seems to have vision problems or has visible cataracts, you should talk to your vet about visiting a canine ophthalmologist. You can learn more about canine eye testing at the Canine Eye Registration Foundation.
Another major eye problem the Jack Russell Terrier may experience is lens displacement, known as luxation. If your dog sees fine one day and is blind the next, he may be experiencing a primary lens luxation. Luxation occurs when the ligament that holds the lens in place allows the lens to slip out of place. Some times, the eye will look completely normal (especially if the lens has slipped to the rear of the eye); other times, you may see a bluish film over the eye (if the lens has slipped forward).
A dog with a hereditary tendency towards primary lens luxation (both parents must carry the gene) may see problems start between the ages of three and eight years. PLL can be treated surgically, but is not always effective. Severe cases may require the removal of the eye.