By the Grace of Dogs Inc., Lakewood Ranch resident sees the light

When he lost most of his sight from 2021 through 2023 due to detached retinas, Lakewood Ranch's Mark Thornsbrough had been thrust into a dark world.

He didn't know it, but his darkest day had yet to arrive.

That came early in 2024 when Thornsbrough was walking through his Country Club East neighborhood with his Labrador retriever, Sully.

Sully wasn't a guide dog, although he was a loving partner who could at least protect Thornsbrough from the threats of impending danger.

From the little things, not so much.

During this particular walk, Thornsbrough, whose limited sight offered no depth perception, hit the right edge of the sidewalk and fell, landing in the grass to his right.

His Apple AirPod flew out of his ear, and he started flailing through the grass in a hopeless attempt to find it.

It is not what he imagined for his golden years.

All his favorite things — running and biking, shooting trap and skeet, driving — were all gone. And there he was, flopping helplessly in the grass. Defeated.

"If it was my time (to die), I wasn't worried about it," he said. "What was I going to do, sit in the house all day?"

A neighbor came to his rescue, and called his wife, Donna, to come pick him up.

Photo by Jay Heater

At that low point, Thornsbrough decided to listen to his neighbor, Lynn McNamee, who had performed volunteer work for Palmetto's Dogs Inc., the nonprofit whose guide, service and therapy dogs had become famous for transforming lives.

"You should think about this," she told Thornsbrough.

Thornsbrough had resisted the urge, because Sully was 6 years old and basically a family member.

"How was Sully going to handle this?" Thornsbrough thought. "Sully was our baby."

The household, however, had deteriorated.

His sister, Rebecca Meeker, was seeing it.

"He was angry," Meeker said. "A lot of things that you or I would be OK with, he was angry about. He couldn't do anything, and he was sitting in a chair most of the day."

Donna Thornsbrough was doing whatever she could to help, but saw her husband slipping away.

"We thought he would get better," she said, wiping her tears away. "There were a lot of emotions. I prayed. The whole thing affected me greatly. I don't think people understand that it affects more than just the person."

Mark Thornsbrough saw what his blindness was doing to his relationship.

"Her life changed as much as mine," he said about Donna. "She put up with a lot. I was like a yo-yo. I was mad at the world. I told Donna, 'You work your whole life ... this ain't worth it."

So he called Dogs Inc.

"There is a test you take that tells you if you qualify," he said. "I need to take some courses."

He took the Lighthouse's adapting to vision loss workshop. It was a six-week course.

"That was the beginning of me coming out and understanding that life was not as bad as it seemed," Thornsbrough said. "I met a guy who was a University of Michigan graduate who still went to the games even though he was blind. He couldn't see, but he was into the crowd there."

Thornsbrough applied to Dogs Inc. in April 2024.

Photo by Jay Heater

Thornsbrough is a retired executive with Growmark, a multinational agricultural cooperative based in Bloomington, Indiana. He had grown up on farms, and noted he had been driving tractors since he was 10 years old, which made losing his driver's license that much more painful.

He was approved in September 2024 and told that Dogs Inc. trainers would eventually bring a few possible matches to his home to see how fast he walked and to find out what he wanted in a dog. That happened in March 2025.

The trainers arrived with three dogs and Thornsbrough said he wanted a dog full of "spit and vinegar." He also wanted a dog who liked to swim, and he was hoping for a black lab, if possible.

All three dogs were black labs.

"Grace was first (to walk with him), and she was full of spit and vinegar," he said. "But didn't know if I could keep up with her. Birdie was next, and she was too slow. Mr. Cinders was third, he was right there. I thought he was perfect."

The next day Thornsbrough was invited to Dogs Inc.

Donna Thornsbrough dropped him off on a Sunday, and he spent the next 19 days on the Dogs Inc. campus, learning what life would be with a guide dog.

On his second day on the campus, Grace walked into his room.

"I was a little scared of Grace," he said. "They told me they thought she was my best match. 'We can always slow a dog down,' they said.

Dogs Inc. trainer Chrissy Sanford said she was confident Thornsbrough and Grace would be a great match.

"It can sometimes be challenging to find a dog who will hold a fast pace for long distances, so when this happens, we match the person with a dog that might be too fast at first," Sanford said. "In our experience, the dogs will usually settle once they’re home and into a routine with their guardian.

"It was fate they were both ready at the same time. It was meant to be." 

Thornsbrough immediately began his long walks around his neighborhood again, although minus the falls.

"If another dog is ahead of us, Gracie speeds up. She doesn't like to be second place, and I adore her for that."

Gracie and Sully hit it off right away, playing together behind Thornsbrough's house and swimming in the pool together. Donna began walking Sully all the time so he didn't feel left out. They said it seemed Sully could understand Mark Thornsbrough's predicament.

"It will be a year March 31," Mark Thornsbrough said. "I am much happier now. When Gracie is working, she takes care of me. When she isn't working, I take care of her. And when we walk, Donna doesn't worry anymore because she knows I am with Gracie."

Meeker, who lives at Del Webb of Lakewood Ranch, has witnessed the transformation in her brother, and she has become a puppy raiser for Dogs Inc.

Mark Thornsbrough now walks with Gracie and wears Ray-Ban Meta glasses that are AI-powered glasses that analyze surroundings via voice commands. But Gracie has an even bigger impact.

"People are in awe of what these dogs can do," he said. "Gracie can find the car for me in a parking lot, or in a hotel, she can take me back to our room."

One of the biggest differences for Thornsbrough, who can see a little stream of light out of one eye, is he can look up when walking with Gracie, instead of staring right down at the ground. At times, he can make out a little patch of blue sky above him.

That makes all the difference.

"Until you see through my eyes, you can't know what I see," he said.