BALTIMORE - Ace, a youthful Labrador, bounds across his lawn, fielding tennis balls and hurrying them back to his owner.

His tail wags. His coat is thick and shiny. He barks with enthusiasm. To the naked eye, Ace is a strapping example of dogdom. Who would guess that he’s had work done?

An eye job, in fact.

Ace is one of thousands of dogs that have had plastic surgery. A little nip. A little tuck. Eye lifts. Nose jobs. Exactly the sorts of procedures people get. But unlike cosmetic surgery for humans, dogs and cats aren’t doing it to look better at their high school reunion.

“We call it cosmetic surgery just because it’s altering an animal’s facial features,” said Dr. Jules Benson, vice president of veterinary services at Petplan, a pet insurance provider. “It changes the look of an animal, but you are doing it to prevent further disease and to better the health of the animal.”

Ken and Jennifer Scaturro of Arnold, Md., brought Ace to their veterinarian two years ago because his eyes wouldn’t stop watering. They’d tear and tear. And they’d see him rubbing at his face with his front paws.

When the vet said Ace might have in-turned eyelids, a common condition called entropion, and directed the family to a plastic surgeon, they had never heard of such a thing for pets.

Plastic surgery? What next - teeth whitening and Perrier in his water bowl?

“I almost thought I was getting scammed a bit,” said Jennifer Scaturro. “I had no idea. But then I thought, ‘People who have skin cancer go to a cosmetic surgeon.’ It seemed reasonable.”

The eye specialist confirmed Ace had entropion, causing his lashes to constantly brush the surface of his eyes. It’s painful and, if untreated, could lead to permanent eye damage. Plastic surgery was the best option, they were told.

So the Scaturros spent $674 on a puppy eyelift, a procedure so subtle it’s hard to detect, even squinting at before-and-after pictures. But one that nevertheless changed their Ace’s life.

“I can’t even imagine having eyelashes in my eyes every single day,” Jennifer Scaturro says. “I think it made his quality of life so much better. His eyes have been great.”

Stories circulate in the pet world about dogs and cats getting slimmed by liposuction and de-wrinkled with Botox. There’s a vet in Brazil who has built a reputation for helping a pet’s droopy ears stand at attention with silicone injections. And for decades, owners aghast after stripping their dog’s manhood have substituted Neuticles for the real thing.

In the United States, purely aesthetic surgeries are rare and generally frowned upon, Benson says. The American Kennel Club forbids cosmetically enhancing a show dog except in cases of breed standards - like tail docking. The Humane Society Veterinary Medical Association campaigns against tail docking, ear cropping, debarking, declawing and any operation an animal doesn’t medically need.

But using plastic surgery for just that has become common.

By far, most pets getting cosmetic surgery are getting eyelifts to correct entropion and nose jobs to fix breathing problems seen regularly in the smooshed-nose, brachycephalic breeds such as pugs and French bulldogs.

In 2011, Petplan’s top year for plastic surgery, the company paid 79 claims for 53 pets to have cosmetic work done. Most of them had either entropion or brachycephalic surgery. The company only covers medically necessary procedures - customers who want synthetic dog testicles are on their own.

Petplan’s plastic surgery claims dropped more than 27 percent in 2012. But the company expects owners to continue choosing it for their pets.

“As an industry, we’re getting much better at addressing life issues sooner than we ever have been before,” Benson says. “More and more people are taking the step, saying is this something we can do.”

Dr. Jennifer Hyman, a veterinarian for Eye Care for Animals in Annapolis, Md., performed Ace’s eye job - and has done dozens of others just like it.

Before becoming an eye specialist, she performed several brow lifts as a general practitioner, including one on a Shar-Pei whose trademark wrinkles were irritating his corneas and another on a bloodhound with facial skin so droopy it shrouded his eyes like curtains. She helped a breathing-impaired pug with a nose job, shortening his soft palate and widening his nostrils.

And yes, if an owner insisted, and she was operating anyway, Hyman would grudgingly agree to Neuticles, knowing a dog could take or leave those particular private parts.

“We all laugh at the idea of Neuticles, but we also feel like they’re pretty harmless, too,” she says. “It makes the people feel better. I don’t think the dogs really care.”