If you noticed your dog recently bumping into objects or having a hard time finding his toys, you may be wondering if there is a way to tell if a dog has gone blind from one eye or perhaps both eyes. Is there such as thing as a dog eyesight test you can do at home? The answer is yes, there are also several dog eyesight tests you can do at home to test your dog's vision, but these don't provide much valuable information as to what may be causing your dog to undergo vision loss in the first place. On top of that, you must consider that if your dog is suffering from recent vision loss, seeing your vet promptly is important as there are certain conditions which, when treated in a timely manner ( usually within 24 hours), can restore vision, or at least partially. These are therefore just preliminary dog eyesight tests you may do at home as you await to see your veterinarian.
Menace Response Test
One way to tell if your dog has still some vision is by performing what is known as the menace response test. This test is based on a dog's blinking reflex which happens in response to an object that is quickly getting close to the eye.
In healthy eyes, upon seeing the object coming near, the dog will blink the eyelids quickly to protect the eyes from potential damage. In a dog who is suffering from vision loss, there may therefore be no defensive response.
To perform the test, you would have to be in a room with normal lighting. You would cover one of your dog's eye so that it doesn't influence the other. You would then move your hand towards your dog's eye from the farthest corner of the eye towards the eye. If your dog can see, you will notice him blinking, if he doesn't, this can be indicative that he is blind, explains veterinarian Dr Gabby.
Now, there are some precautions that need to be taken during this test. For instance, attention should be paid to not cause any airflow in the movement as the dog may detect it and reflexively blink. Also, you have to avoid touching any of the dog's whiskers as this could elicit the dog to reflexively blink, explains Noelle La Croix, a board-certified veterinary ophthalmologist.
The Cotton Ball Test
This test is used to track a dog's tendency to follow movements. Dog eyes are particularly adept at following movement considering the dog's history as a hunter catching fast moving prey. Failure to follow movement may be indicative of loss of vision. In this test, all you will need is a well-lit area and a cotton ball.
Start by covering one of your dog's eyes so it would not influence the other. Next, drop a cotton ball above the other eye at a distance of about 6 inches away. Since cotton balls do not make any noise when they land, this test will provide information on the dog's instinctual ability to track its movement, explains veterinarian Dr. Altman.
Many dogs will not only move their eye but will also try to catch the cotton ball or sniff it once it lands on the floor. However, not all dogs will do this. To ensure an accurate test, it may help to have a helper carefully look at the dog's eye to detect any slight movements following the cotton ball. Making a video of the test can also provide some further insights.
The Flashlight Test
In normal, healthy eyes, the pupils will dilate when in dark conditions and will constrict when they are exposed to light.
Eyes that stay dilated even when a light is shone over them, is indicative that the eyes are no longer capable of detecting the light on the back of the eye, explains veterinarian Dr. Christian K.
When the dog's retina is therefore no longer responsive to light it's a sign that the eye has gone blind.
In order to perform this test, you will have to be in a dim room and then shine the flashlight in both eyes keeping it about 1 to 2 inches away. In a dog with good vision, both pupils should get smaller, explains veterinarian Dr. Fiona.
The Obstacle Course Test
Figuring out whether a dog is blind is often challenging in a home setting because dogs have the uncanny ability to memorize the layout of the home. Many blind dogs start to struggled once their owners start re-arranging furniture.
To test your dog's vision, you may therefore try to set up an obstacle course. You don't have to arrange furniture around for this test instead, you can simply place several garbage pails around passageways and evaluate how well your dog does navigates through them.
You can try doing this test at different times of the day in different light conditions considering that often dogs tend to see better during the day than at night, points out Dr. Altman.
Importance of Seeing Your Vet
As seen, these tests can provide an insight about your dog's vision, but as mentioned these dog eyesight tests should not stop you from seeing your vet. Only your vet can diagnose eye conditions in your dog, and when it comes to eye disorders, time is of the essence. Eye problems in dogs should be seen within 24 hours. Also, consider that eye problem can be caused by underlying health problems that may need to be addressed. So if you notice any changes in your dog's eyes or vision, please see your vet promptly for proper diagnosis and treatment.
- Veterinary Medical Center of Long Island: The Ophthalmic Examination (Part 1)