Diana Nyad wore a special mask to protect her from box jellyfish. (Image Credit: diananyad.com)

On her 5th attempt, endurance swimmer Diana Nyad, 64, made history today when she became the first person to swim from Cuba to Florida without a shark cage. While the bulk of her accomplishment can be credited to preparation and perseverance, a specially designed face mask also helped.

After a jellyfish sting to the lips thwarted Nyad's previous attempt in 2011, the decision was made to wear a custom-molded silicone mask during the 2013 effort. Stephan Knauss of Aesthetic Prosthetics in Pasadena, Calif., designed the mask after those used by patients who have suffered facial injuries.

"We must have made about six of them before we got to the current one," said Knauss, who, along with colleagues Gina Cohen and Mason Trager, created the mask in varying thicknesses from 80-shore durometer (a measure of hardness) around the eyes to 20-shore durometer closer to the lips.

Knauss also collaborated with a dentist in Orange County who created acrylic mouthpieces. All of this was pulled over Nyad's head with a spandex-nylon hood.

Box jellyfish are common to the Florida Straits. A highly venomous creature, its sting can be deadly. They are also particularly difficult to see at night. To test out the mask, Nyad wore one while swimming through a swarm of box jellyfish in June, according to her web site.

In addition to the mask, Nyad was also monitored by Dr. Angel Yanagihara, leader of the Nyad's Jellyfish Safety team, who developed a topical cream called "sting-stopper" that was applied to the endurance swimmer's hands, feet and face.

"We've now formulated it into this anhydrous lanolin base which is very stable in the marine environment, so that an ocean swimmer can swim for up to 90 minutes in the water," Yanagihara wrote on Nyad's site. "It has loads of this inhibitor that prevents the tentacles from discharging as well treating any potential stings."

Because of the mask's restrictive nature, Nyad initially found it difficult to swim with and wore just the topical cream at the beginning of her journey, according to her site. But as soon as jellyfish were spotted, the team switched back to the mask.

"I'm very proud of her," Knauss said. "It's incredibly remarkable and I'm just delighted that I could be of some assistance."