Shining a Light on Senior Eye Exams
Eye conditions are common in dogs, but there’s a vast spectrum between situations that are a normal progression based on age and diseases that need treatment throughout your dog’s lifetime. Educating yourself on the signs and symptoms of eye conditions is the second-best thing you can do to help your dog have good vision for as long as possible.
What is Iris Atrophy?
Iris atrophy is common in senior dogs. It refers to the atrophy of the iris muscle in the eye over time. The iris is the colored part of the eye, consisting of two muscles that work in tandem to control how much light reaches the pupil. Further, depending on the amount of light available, the iris controls the size of the pupil.
As a dog ages, it’s common for the iris muscle to weaken. When this occurs, it makes it harder for the iris sphincter muscle to constrict the pupil, letting too much light enter. A common observation is overly squinting on bright clear days.
Another thing you might notice is that your dog’s eyes seem shinier at night; this is a light reflection in the back of the eye (often referred to as "eye shine.")
Other symptoms that are sometimes noticeable with iris atrophy include holes in the iris itself, rough edges around the pupil, and unequal pupil sizes (or sometimes what looks like a double pupil).
Because this is a common condition associated with aging, iris atrophy on its own is not something typically treated. Once confirmed by your veterinarian, consider purchasing tinted Doggles for outdoor use.
Caution to Self-Diagnosing Parents
Given rising vet fees, it’s tempting to turn to Dr. Google for free advice, but it’s an error in judgment. The same signs and symptoms can also exhibit in more severe conditions such as cranial nerve abnormalities, Horner’s syndrome, glaucoma, and Progressive Retina Atrophy, among others where treatment may be available and needed.
If you notice any of these signs, be sure to make an appointment with a professional for a complete diagnosis. As recommended above, annual eye exams are the best tool to ensure you catch an eye condition as early as possible.
Progressive Retinal Atrophy (PRA)
Unlike iris atrophy, Progressive Retinal Atrophy (PRA) is inherited and progresses over time to cause either partial or complete blindness. Created by a defective enzyme that "attacks" the retina by killing off healthy cells.
Critical to eyesight, the retina is the part of the eye that creates a visual image that is then sent to the brain through the optic nerve.
In the retina, the ability to have vision comes from photoreceptor cells. There are two types of these cells in dogs: "rods," which are responsible for vision in dim light, and "cones," which are responsible for vision in bright light and for seeing color.
PRA Signs and Symptoms
With PRA, the "rod" cells are the first to be attacked, so often, the first sign of PRA will be your dog having trouble seeing at night or having complete night-blindness. If your dog is bumping into things at night or seems utterly blind at night, get to a veterinary ophthalmologist ASAP.
Eventually, PRA attacks the "cones" as well, causing progressive loss of all vision and usually complete blindness. Since PRA is progressive and depends on how quickly it moves, a dog’s ability to adapt can often make it hard for an owner to notice the vision loss.
Typically, it’s not until eighty percent of vision impairment has occurred that parents will begin to see behavioral clues.
There is currently no cure for PRA, although some ophthalmologists have begun to utilize antioxidant support and vision supplements to help retinal health and protect some daytime vision. Although this approach is not proven to change the outcome, many success stories of dogs with PRA have retained some daytime vision through the end of their life.
Even though there’s no cure for PRA, it’s still essential to have it adequately diagnosed as it can lead to other eye conditions. PRA is not painful but can lead to advanced cataracts (which can cause inflammation and become painful) and glaucoma (very painful).
#1 Wellness Priority: Annual Eye Exam
Identifies if your companion shows early signs of progressive disease or a condition.
If your companion is diagnosed with PRA or Iris Atrophy, he can live a happy and healthy life. Blindness is not the end of the world. However, know that your companion is at a higher risk for eye injuries. Consider helping him to navigate the world safely:
Indoors: Avoid moving furniture, and food/water bowls
Outdoors: Purchasing tinted dog goggles is a safety measure to avoid injury when walking on trails or in unfamiliar places.
Canine companionship is about journeying through life together and creating memories. As caregivers, we can help our companions enjoy all that life offers, remembered not by regret but by sunrays of Love.