Like many puppies, Tucker loves a good chase. But the 9-month-old chocolate Labrador wasn’t always able to see a squirrel dart across his path or a ball thrown in his direction. Until recently, cataracts caused by juvenile onset diabetes limited the puppy’s vision in both eyes.
“Tucker was just a few months old when we got him,” said Ellen Caplan, his owner. “I knew immediately something was wrong—he was very thin and constantly thirsty. His blood sugar level was more than 700, much higher than the normal level of a healthy dog.”
Tucker received the very rare diagnosis of juvenile onset diabetes, and Ellen sought multiple opinions about treatment. “The veterinarians we consulted had never even seen a case of the disease,” she remembered. “Many people would have written this dog off—some suggested we send him back to the breeder or to a rescue for sick animals. This was out of the question. Tucker is part of our family.”
Eager for expertise, Ellen learned about Ryan Hospital’s Dr. Rebecka S. Hess, Professor and Section Chief of Internal Medicine, through online research. Hess, a foremost diabetes researcher and clinician, offered hope. “Dr. Hess was wonderful from our initial meeting,” Ellen explained. “She said ‘this is nothing, I’ve got this.’—words I needed to hear.”
Hess, who sees approximately six cases of juvenile diabetic dogs annually and knows of only one recorded case of a Labrador with the disease, reassured Ellen that the condition is treatable, if somewhat complex.
“Although manageable, juvenile onset diabetes is more difficult to treat than older age onset diabetes because puppies are in constant flux,” Hess explained. “Generally, we determine an insulin dose based on a dog’s weight and the amount of food the dog eats. In puppies, these variables change weekly, making treatment challenging. The metabolic rate of puppies is also higher than that of adult dogs. Standard insulin doses and dietary recommendations just don't work for young dogs, so diabetic puppies require customized treatment. More than anything else, treating them requires patience.”
Tucker was malnourished when Hess met him. Her first steps were to increase his weight and get his glucose under control with the appropriate insulin dose. While glucose regulation was a challenging journey, stabilizing his diabetes was a crucial step to help Tucker tackle the next hurdle he was about to face. He quickly lost his vision to cataracts, a common side effect of diabetes.
“We knew that Tucker would get diabetic cataracts but not when,” said Dr. Brady Beale, Ryan Hospital Clinical Instructor and a cataract surgery specialist. “Unfortunately, they developed very quickly. Three months after his first appointment with me he had complete cataracts in both eyes.”
Tucker, by all accounts a happy puppy, was suddenly only able to see shapes and shadows. Surgery could remove the cataracts, but he wasn’t necessarily a good candidate.
“We had to determine whether his blood glucose was stable enough to undergo general anesthesia and then handle post-surgery topical steroid drops, which increase blood glucose,” Beale explained.
And because of a birth defect in the puppy’s left eye of a small loose lens—or posterior subluxation—that poses a higher risk of complications like glaucoma or retinal detachment, he would ultimately only qualify for surgery in the right eye.
But qualify he did, and on a frigidly cold morning in January, Tucker arrived at Ryan Hospital for what would be a life changing operation.
Surgery... And Surprises
In prep for surgery, Tucker received a series of eye drops before going under general anesthesia. Beale began the procedure by making a small incision in the cornea to gain access to the lens capsule surrounding the cataract. Here the surgical team had its first surprise. The cataract had stretched Tucker’s lens capsule tissue dangerously thin.
“I have never encountered such a thin lens capsule—imagine the thinnest tissue paper,” said Beale. “We had to proceed very gingerly.”
Once Beale carefully opened the lens capsule, she used phacoemulsification, a procedure that uses ultrasonic waves to break up and aspirate the cataract.
Then came the next hurdle.
After removing the cataract, Beale was ready to insert an intraocular, or artificial, lens into the capsular bag when she discovered a posterior subluxation—the same congenital defect as in his left eye. She explained, “We had to use a capsular stabilization ring on the lens capsule before implanting the artificial lens.”
The acrylic ring helps hold the capsule in place to secure the capsular bag permanently.
“We rarely get to use this technology, so it was exciting for everyone involved in the surgery—and it worked,” Beale said. “We placed the artificial lens, centered it, and closed the incision with 8-0 vicryl suture—a tiny suture, thinner than a strand of hair.”
After a successful surgery and post-op recovery, Tucker went home later that day.
“This ended up being a very rewarding procedure for Tucker and his family,” said Beale. “And since we encountered some expected and unexpected complications, it was also a tremendous learning experience for residents and students.”
New Day, New Sights
By the next morning, Tucker was up and about enjoying new sights. “He’s a completely different dog; our walks are much more exciting,” laughed Ellen. “We are so grateful to the Penn Vet team—Drs. Hess and Beale and the wonderful nurses and staff at every point of our visits, from the parking lot to discharge.”
According to Hess, Ellen’s commitment to Tucker is a major factor in the puppy’s overall success. “Ellen is incredibly devoted to Tucker,” said Hess, who is currently conducting a survey about diabetes in dogs. “Caring for a puppy with diabetes takes a lot of work, a significant emotional and time commitment, and funds. For Ellen, the question was always how—not if—to treat Tucker. That’s made all the difference.”