When a person gets an eye exam, they’re asked to read letters from a chart—but what about dogs? Since our four-legged friends can’t tell us what they’re experiencing, veterinarians know very little about canine vision. Recently, scientists conducted a study they hope will lead to new information about how well dogs see as they age.

The study from the University of Wisconsin School of Veterinary Medicine was the first step in a larger investigation that uses videos to learn about dog vision. In this early step, scientists wanted to see which videos dogs like best. They asked 1,246 people to observe which videos their dogs paid the closest attention to (a sign that the dogs want to watch) and then answer some questions online. The dog owners also noted their dogs’ breeds and their ages because scientists know that, as with people, dogs’ vision often gets worse as they age.

The study found that dogs enjoy watching videos showing other animals, especially other dogs! They weren’t very interested in watching videos of humans, though. More than 10 percent of the dogs seemed to like cartoons. That could be because, overall, movement on the screen got the dogs’ attention, and cartoons have a lot of that! Scientists noticed that the age and breed of the dog seems to affect how much it’s interested in watching TV.

Now that scientists have this information, they want to do a study that uses video-watching to track vision changes in dogs as they age, veterinary ophthalmologist (eye specialist) Freya Mowat told Spectrum News 1 in Wisconsin.

“The effect of aging and vision changes in dogs is largely unknown,” Mowat said. “Like people, dogs are living longer, and we want to make sure we support a healthier life for them as well.”