Kylee Vollmar and Natassia Strayer cautiously approached a tall, blonde-haired woman as she stood by an ATM.

"Are you my mother?" the two 13-year-old students at Casper Classical Academy asked quietly.

"Only on Wednesdays," the woman said, smiling at the girls.

In a fit of giggles, Kylee and Natassia handed over a thick piece of paper, which the woman signed with a flourish.

"We just met Hannah Montana," Natassia laughed.

Kylee and Natassia were just two of the many Casper Classical Academy students who took over Eastridge Mall Friday evening for a human scavenger hunt.

Students hosted the hunt to benefit their classmate Matthew Stairs, who has Stargardt's Disease. Stargardt's is a genetic, degenerative eye disease.

With Stargardt's, particles harmful to the eye collect on the back of the retina. Those particles would normally be blocked from the retina by a protective layer.

Teachers and community members dressed in outrageous outfits and milled about the mall, waiting for students to find them. Students were told to ask, "Are you my mother?" to anyone who looked like they might be part of the scavenger hunt. If the person was a suspect, he or she would answer, "Only on Wednesdays."

Kylee and Natassia both know Matthew from various after-school activities. Both girls said they were happy to participate in the scavenger hunt and help out one of their classmates.

"Matthew is really nice, and he cares about everyone," Natassia said.

Anyone wishing to take part in the hunt contributed $10 and Wyoming Medical Associates donated $1,000 to the Stairs family. The money will be used to defray the cost for Matthew to take part in a new clinical trial.

The trial, which uses gene therapy, could actually make it possible for Matthew to see fully again, said Nina Stairs, Matthew's mother. Proceeds from the scavenger hunt will go toward paying for Matthew to be part of the trial. The trial is not yet approved by the Federal Drug Administration, and as such, is not covered by insurance.

Stairs said her son's vision has decreased to a point where the usual treatments for Stargardt's won't really benefit his sight.

"We're hoping to reverse the effect, rather than just improve his vision," she said.

The possibility of Matthew taking part in a clinical trial not yet approved by the FDA didn't worry Stairs too much. Many procedures available work just fine and can take years to make it through the approvals process, Stairs said.

"I know that there's a lot of things that aren't FDA approved," she said. "Matthew is just such an awesome kid, and we just want to try to help him as much as possible."

Reach education reporter Jasa Santos at (307) 266-0593 or at Jasa.Santos@trib.com.