What it is
The retina is the thin, light-sensitive layer at the back of the eye. It holds two kinds of cells: rods, which see in dim light and pick up movement, and cones, which work in bright light and give detail. In this condition these cells slowly die. In the classic course the rods go first, which is why night vision fades before day vision.
The disease is inherited, and different forms are caused by different genes. Depending on the form, the first changes can appear in a young dog or only in middle age.
Because the loss is gradual and painless, a dog adjusts as it goes, relying more and more on its nose and hearing, and its family may notice only when it is somewhere unfamiliar. Keep the furniture where it is, block off the stairs, speak to your dog as you approach, and walks on familiar routes stay a pleasure.
Signs you may notice
- Hesitates in the dark
- Bumps into things at night
- Unsure on stairs
- Pupils look wide
- Eyes shine in the light
The first change is poorer vision in dim light: the dog hesitates in the dark or on stairs and bumps into things it easily avoids in daylight. Later the pupils may look dilated and the eyes may reflect light more noticeably.
When to see a vet
Book an eye examination if your dog seems less sure of itself in dim light, bumps into things or its eyes look different from before.
This is general information, not veterinary advice. For your own dog's health, tests and treatment, see a vet.