In his speech in Tucson Wednesday, President Obama made the surprise announcement that Giffords, who was shot in the head Saturday at an event, opened her eyes for the time.
"A few minutes after we left her room and some of her colleagues from Congress were there, Gabby opened her eyes for the first time," said Mr. Obama.
Scroll down to watch video of Mr. Obama announcing Rep. Giffords opened her eyes.
CBS Evening News anchor Katie Couric reports it was a major moment in Wednesday's emotional memorial service and doctors say it's a major milestone for Giffords. Shortly before the service, surrounded by her husband Mark Kelly, Minority Leader Nancy Pelosi and her close friends Rep. Debbie Wasserman Schultz (D-Fla.) and Sen. Kirsten Gillibrand (D-N.Y.), she opened her eyes.
Sen. Kirsten Gillibrand: "She's in her hospital bed. I'm holding her hand, we're talking about how great she is and how inspiring she is. And we're talking about all the fun things we want to do. And she's squeezing my hand and I'm knowing that she's reacting. She's moving her leg and she's moving her arms. And we're getting so excited because we can see that she's really trying so hard to communicate with us."
Dr. Michael Lemole, the neurosurgeon who operated on Giffords, said Thursday that visit may have made all the difference.
"I was there when she was surrounded by her friends from the Congress and the Senate. And I think it was a combination, perhaps, of the unexpected but familiar that really prompted her to open her eyes and look around," he said.
Katie Couric: "Was her husband completely beside himself?"
Gillibrand: "He was - it was dramatic. I mean, he - we didn't understand the importance of that. We didn't know that she had not opened her eyes. But what - when we watched Mark, we knew. We - because he was just, 'Gabby, can you see me, can you see me?' And that love was so palpable. And you could just see that he was going to bring her over the finish line with his own bare hands."
On Thursday doctors said the development was a sign they could begin more aggressive physical therapy on Giffords. They held her up in bed and dangled her feet over the side, and when asked she moved both legs on command. Her attempt to focus her open eyes has been the most encouraging development yet.
"It's like in the morning when you get up for work and you're about to have your cup of coffee, she's arousing and then the eyes stay open, stays open for long periods of time, and then when you put stimulation in front of her, you can tell that she can see," said Dr. Peter Rhee.
Giffords remains in critical condition and, as her doctors have reported, recovery will be measured not in days or hours but in months. Still, to the friends and family members who thought they'd never see her again, her progress is nothing short of a miraculous.
"Miracles happen every day," said Lemole. "And in medicine we like to very much attribute them to either what we do or others do around us, but a lot of medicine is outside of our control and we're wise to acknowledge miracles."
Couric: "What is the first thing you'd like to do with Gabby when she's well enough?"
Gillibrand: "Hug her. I just want to hug her."