Brad Snyder, who lost his sight while serving his country, conquers treacherous Alcatraz swim

One, two, three, four ...

Brad Snyder managed to block out every next thought, every painful memory, every unwritten plan, and remain focused on the revolving numbers in his head.

24, 25, 26, 27 ...

With every long, powerful stroke -- the thrusts he learned as a child growing up in Florida, polished as captain of the Naval Academy's swim team, and brought back to life while winning five gold medals at the last two Paralympics -- Snyder kept his mind concentrated on pulling his body to a shoreline he'd never see.

56, 57, 58, 59 ...

Even before losing his eyesight in a roadside bombing in Afghanistan six years ago, swimming in chilly ocean temperatures didn't come naturally to the Gulf Coast native. So Snyder stayed locked in on his numbers Sunday morning, counting each stroke as he churned through the treacherous 2.1 miles from Alcatraz Island to a sandy beach just east of the Golden Gate Bridge in San Francisco.

79, 80 -- one, two ...

Since going blind, Snyder has learned that it usually takes about 40 strokes to swim from one end of a 50-meter pool to the other, so he did his math and concluded the swim from Alcatraz to Crissy Field would require approximately 30 sets of 80 strokes. When he heard a mile remained in Sunday's swim, he figured he needed another 15 sets of 80.

So he began counting.

"I break things up like that in my mind, just so I can have a perception of progress," he said.

Snyder's successful completion of Sunday's swim is the latest sign of progress for the 32-year-old former Navy seaman.

An explosive ordnance disposal officer on his second tour of duty, Snyder had his life altered Sept. 7, 2011, when he ran to the aid of some locals who had been severely injured by an improvised explosive device and Snyder stepped on another IED concealed nearby.

Remarkably, his injuries were mostly confined to his facial area, but he lost sight in both eyes. Snyder spent 60 hours in a medically induced coma before awakening to a world of permanent darkness.

He continued his recovery at a veteran's hospital in Tampa, Florida, where he also began relearning life's basic functions, tasks previously as routine as putting the right amount of toothpaste on his brush.

His rehabilitation also took him back to the water, where he quickly discovered his injuries didn't prevent him from swimming -- just safely navigating through a pool. Four months after his injury, Snyder was recruited for the Paralympics, an event he never knew existed before he lost his eyesight.

Never unwilling to test his limits, Snyder decided to give the event a try. One year to the day after his injury, he won the second of his two gold medals in London. He also won a silver there.

He returned to the Paralympics this summer in Rio de Janeiro and took home three more golds plus a silver, and he broke a 30-year-old record in the 100 freestyle in his visually impaired class.

When asked to participate in the Alcatraz Swim for Sight, which benefits the support foundation of the UC San Francisco Ophthalmology Department, Snyder immediately knew his involvement would be a great way to help the cause while also testing his swimming abilities in a different way.

He spent a restful Saturday night in Fisherman's Wharf and then joined about 100 others on a half-dozen boats that took them to the edge of Alcatraz, a maximum-security federal prison from 1933-63 that is now a tourist attraction. The rock island was considered an ideal penal location because the cold temperatures of the San Francisco Bay, powerful currents and distance from the mainland made it nearly impossible for prisoners to escape.

Slipping into his wet suit, climbing aboard a military-style Zodiac boat, and feeling the saltwater mist spray over the bow and onto his face reminded Snyder of his days performing dive operations for the Navy.

"It made me feel kind of grounded to my past," he said. "It allowed me to have some fun with it."

Guiding him through the swim was Jill Dahle, whose sister was treated for a rare eye disease at UCSF when she was a child, and lead swimmer Bryn Lewis. Snyder and Dahle knew each other professionally but had never swum together.

While waiting on the pier for a boat to take them to Alcatraz, Snyder showed Dahle the 3-foot bungee cord that would tether them together side by side. They briefly discussed the basics of their buddy system and then followed their instincts in the water.

"Brad is a beautiful swimmer," Dahle said. "I breathe to my right, so I saw him every stroke. It felt very harmonious several times as we were taking strokes at the exact same time. ... Just being able to see that, I felt fortunate."

Snyder had dipped his toes in the water prior to diving in but was still relieved by the 60-degree ocean temperatures. He had been told to expect conditions closer to the mid-40s.

That wasn't all that was optimal on Sunday for open-water swimming. The sun was shining on their backs, the currents were mild, no obstacles (such as floating kelp) arose, and the only marine life in the area was a small group of sea lions lounging on the buoys. (Great white sharks have been spotted near Alcatraz.)

"A really unique case in which all of the conditions were in our favor," Snyder said.

The most jostling Snyder felt was about a half-mile before the finish, but even those swells were more annoyance than hindrance. When they were a few hundred yards from the beach, Dahle gave Snyder a tap on the shoulder. Snyder initially thought she was letting him know they'd finished, but he quickly realized a short distance still remained.

That was perfectly OK with Snyder.

"It really didn't feel that long. It felt like 20 minutes," he said by phone after completing the swim in just under an hour. "That's kind of indicative of it being an enjoyable time."

Snyder said he's ready to take a step back now that the open-water swim is concluded. He has done a triathlon in the past but isn't sure if that's something he wants to pursue full time. The next Paralympics are still four years away.

"I don't know what's next on the horizon," he said. "I really want to take some time off to allow my mind to not be thinking about Rio, or what event I have to do, or all these other things. ... I'd love to enjoy some spare time, let my mind wander, let me ask those difficult questions. Who am I? Who do I want to be, and what do I want my contributions to society to be? Is it to remain in sports? I definitely think changing it up will be fun."

Let the next countdown begin.